KR20080082109A - Protein marker flavin reductase for breast cancer diagnosis and diagnosis kit for breast cancer using antibody against the same - Google Patents

Abstract

A breast cancer diagnostic kit comprising an antibody specific to a flavin reductase protein marker is provided to show high specificity and accuracy of diagnosis and diagnose the breast cancer very conveniently using blood of a patient, thereby being usefully used for an early diagnosis of the breast cancer. A kit for diagnosing breast cancer comprises an antibody specific to a flavin reductase protein marker having an amino acid sequence of SEQ ID : NO. 1. The kit further comprises a secondary antibody conjugate where a marker colored by a reaction with a substrate is conjugated, a coloring substrate solution which is subject to the color reaction with the marker, a washing solution and an enzyme reaction stopping solution. Further, the antibody is multi-clone antibody or single-clone antibody.

Description

PROTEIN MARKER FLAVIN REDUCTASE FOR BREAST CANCER DIAGNOSIS AND DIAGNOSIS KIT FOR BREAST CANCER USING ANTIBODY AGAINST THE SAME}

1 is labeled with a cleavable isotope-coded affinity tag (cICAT) reagent substituted with a light isotope and a heavy isotope, and digested with trypsin, and then identified and quantified by mass spectrometry. Shows chromatograms of two isotopic pairs of peptides with increased expression in the patient group,

Figures 2a and 2b are the Fig. 1 specifically in breast cancer patients typically express both the sequence number found to be increased: the cICAT of a peptide having an amino acid sequence of the second light isotopes (2a) respectively with heavier isotopes (2b) After labeling, the result is analyzed by tandem mass spectrometry,

3 is a result of immunoblotting with anti-flavin reductase antibody after analyzing the plasma of the non-patient control group and the plasma of the breast cancer patient group by electrophoresis.

Figure 4 is a graph showing the antigen concentration of the flavin reductase measured by the immunoblotting of Figure 3 above.

The present invention relates to a breast cancer diagnostic kit comprising a flavin reductase as a protein marker capable of selectively diagnosing the development of breast cancer in the blood and an antibody that specifically recognizes it.

Currently, various factors such as female hormones, family history, past history, fertility, and dietary habits have been discussed as the causes of breast cancer, but there is no clear explanation yet. According to a survey by the National Statistical Office in 2005, breast cancer in Korean women has recently increased rapidly, exceeding cervical cancer in 1998, accounting for 16.1% of Korean cancer patients in 2001, surpassing stomach cancer, becoming the number one female cancer. In 2002, breast cancer (11.1%) was the most rapid cancer compared to 2001, and female hormones were stimulated during physiologically active physical changes with factors such as low birth, short lactation, early menarche and late menopause. The incidence of breast cancer is increasing rapidly due to the increased sensitivity of the mammary gland tissues due to the rapid increase in the number of times of receiving cancer, the westernization of the diet, and the pollution of the living environment.

The increase in the incidence of breast cancer and mortality due to breast cancer is expected to continue for some time in view of the current westernization. Breast cancer usually causes symptoms such as invasion of surrounding tissues or lymph node metastasis due to the growth of cancer cells, but most of them can be diagnosed by self-examination without any symptoms. Therefore, it is very important to effectively and early diagnose breast cancer in order to reduce mortality from breast cancer (Tuli R. et al., Breast J. , 12: 343-348, 2006).

Various methods are used to diagnose breast cancer. To date, 70% of breast cancer patients come by self-diagnosis. However, this self-diagnosis method has a disadvantage in that it is very difficult to distinguish between malignant tumors and benign nodules. In addition, X-ray mammography, ultrasonography, fine needle aspiration cytology, magnetic resonance imaging, etc. are diagnosed as breast cancer, and finally, it is important to confirm through histological examination. X-ray mammography is an excellent method for screening breasts with X-rays to distinguish whether the bumps are benign or malignant, and to detect hidden nodules before they are touched by self-diagnosis. It is the most effective way to diagnose breast cancer. However, mammography has a disadvantage in that a lot of mammary glands are developed like young women, or in Korean women with small breasts and a lot of fiber, the diagnosis rate is lowered, and frequent taking may cause breast cancer. Ultrasonography is used as an alternative to mammography, which is effective in distinguishing between water nodules and hard nodules, but lacks the ability to differentiate between benign tumors and benign nodules.

In order to make up for the shortcomings of these conventional diagnostic methods, there have been attempts to diagnose breast cancer by measuring the concentration of tumor markers in the blood of patients (Clinton SR. Et al., Biomed . Sci . Instrum. , 39: 408-414, 2003; Rui Z. et al., Proteomics , 3: 433-439, 2003; Soletormos G. et al., Dan . Med . Bull . , 48: 229-255, 2001). However, although the value of such tumor markers as a diagnostic or prognostic factor has been studied, there are no breast cancer markers that are officially recommended due to their limited use.

Flavin reductase is a water-soluble protein, produced mainly in the liver or red blood cells, present in small amounts in the heart, lung, adrenal gland, or cerebrum, and is also known as biliverdin reductase. This enzyme catalyzes the reduction of flavin mononucleotides, methylene blue, and methemoglobin using NADPH as a reducing agent (Sass MD. Et al., J. Lab . Clin . .. Med 70: 760-767, 1967 ; Quandt KS et al, Proc Natl Acad Sci USA, 91:...... 9322-9326, 1994). Flavin reductase also prevents cells from being damaged by oxidation and is involved in the regulation of iron metabolism, and in the liver plays a role in converting biliverdine to bilirubin. Recent reports have shown that deficiency of biliberdine reductase increases cell damage, increases cancer cell development and brain cell damage, and kills cells even when treated with small amounts of hydrogen peroxide. The proliferation of cancer cells has been reported (Baranano DE. Et al. Proc . Natl . Acad . Sci . USA , 99: 16093-16098, 2002; Rao P. et al., Biochem . Biophys . Res . Commun . , 342: 1279-1283, 2006). In addition, the expression level of flavin reductase was increased in the cancer tissues extracted from liver, oral squamous cell, and renal cancer patients (Maines MD. Et al., J. Urol . , 162: 1467-1472). , 1999; Melle C. et al, J. Proteome Res, 6: 306-315, 2007; Lo WY et al, Clin Chim Acta, 376:....... 101-107, 2007), particularly kidney cancer It has been reported that the amount of plybin reductase is directly related to enzyme activity (Maines MD. Et al., J. Urol . , 162: 1467-1472, 1999). However, studies on the amount of expression of the flavin reductase protein in the blood with respect to cancer have not been reported yet.

Accordingly, the present inventors have made intensive studies to find a method for detecting a specific protein in a biological sample obtained from a breast cancer patient and using the same for early diagnosis of breast cancer. The present invention was completed by discovering that the amount of blood in the blood cells was specifically increased and confirming that breast cancer could be easily diagnosed by an immunochemical method using the antibody thereof.

Accordingly, it is an object of the present invention to provide a method for easily diagnosing breast cancer using flavin reductase present in blood.

In order to achieve the above object, the present invention provides a protein marker for breast cancer diagnosis of flavin reductase having an amino acid sequence of SEQ ID NO: 1 .

The present invention also provides a breast cancer diagnostic kit comprising an antibody that selectively recognizes the flavin reductase protein marker.

In addition, the present invention provides a method for detecting a flavin reductase protein marker through an antigen-antibody binding reaction in a sample.

Hereinafter, the present invention will be described in detail.

According to one aspect of the invention, the present invention provides a flavin reductase protein marker having an amino acid sequence of SEQ ID NO: 1 as a protein marker for breast cancer diagnosis.

In order to select a diagnostic marker which can be usefully used for the diagnosis of breast cancer due to its specific increase in the blood of breast cancer patients, the present invention uses a mass spectrometer to label a protein with a cICAT (cleavable isotope-coded affinity tag) reagent. Use quantitative methods. cICAT is a reagent developed specifically to react with thiols and uses a linker in which all nine carbons are substituted with light isotopes ( ¹² C) or heavy isotopes ( ¹³ C). It contains two different types of isotope tags. Thus, two types of cICAT reagents with the same chemical properties but with a 9 Da mass difference are labeled with cysteine residues of the proteins in the two samples to be compared and cut with trypsin to collect only labeled peptides. Identification and quantitation with an analyzer can identify proteins with quantitative differences in the two samples (Gygi SP. Et al., Nat. Biotechnol . , 17: 994-999, 1999).

In the present invention, the plasma and non-patient plasma samples of the breast cancer patients and the non-patient control plasma samples are first prepared separately for the cIACT analysis. Since few proteins make up the majority of plasma protein concentrations in human plasma, relatively large amounts of proteins must first be removed to identify small amounts of proteins (Anderson NL. Et al., Mol . Cell . Proteomics, 1:.... .. 845-867, 2002; Somiari RI et al, J. Chromatogr B Analyt Technol Biomed Life Sci . , 815: 215-225, 2005). Relatively high amounts of proteins such as albumin, immunoglobulin A, immunoglobulin G, heptoglobin, trasnferrin, trypsin inhibitor, and the like are removed from the plasma samples of the prepared breast cancer patients and non-patient controls. To perform the liquid chromatography using a multiple affinity column. Protein compartments not bound to the column were tracked with ultraviolet absorbance at 280 nm and collected to remove proteins bound to the column. The plasma protein compartment from which the six relatively large amounts of proteins were mostly removed was concentrated to concentrate only proteins having a size of 3 kDa or more, and then the protein samples of the non-patient control group and the breast cancer patient group were light cICAT reagent and heavy cICAT, respectively. Labeled with reagents, mixed in equal amounts, trypsin treated to cleave into multiple peptide fragments. The peptide fragments thus obtained are divided into a plurality of fractions using strong cation exchange resin column chromatography, and only the peptides to which cICAT reagent is bound are separated and concentrated from each fraction by avidin affinity column chromatography. Concentrated peptide fragments are separated via reverse phase resin chromatography system and tandem mass spectrometry is used to obtain tandem mass spectra of each peptide fragment. A computer analysis program compares the tandem mass spectrometry information of peptide fragments with a known protein database to identify proteins and analyze quantitative differences between breast cancer patient groups and non-patient control samples (see FIGS. 1 and 2 ). et al, Anal Chem, 15: 5395-5392, 2002; Nesvizhskii AI et al, Anal Chem, 75:........... 4646-4658, 2003; Li XJ et al, Anal Chem, 75 : 6648-6657, 2003). From this, a flavin reductase protein having an amino acid sequence as set forth in SEQ ID NO: 1 was identified as a protein with an increased expression level in breast cancer patient groups as compared to a non-patient control group.

In the present invention, the present invention is the first use of a flavin reductase protein, which has been shown to specifically increase in the blood of breast cancer patients, as a diagnostic marker for breast cancer. In addition, since the protein can be detected in plasma, unlike the conventional protein, which can be diagnosed only through biopsy, the protein can be used to diagnose breast cancer in a convenient manner without causing inconvenience to the patient.

In the present invention, it was found that the amount of the flavin reductase specifically increased only in the blood of breast cancer patients, and the immunochemistry of non-patient controls and breast cancer patient plasma samples using antibodies that selectively recognize the flavin reductase. Significant results were obtained from the analysis (see FIGS. 3 and 4 ), confirming that the flavin reductase could be usefully used as a diagnostic marker for breast cancer.

According to an embodiment of the present invention, whether or not the onset of breast cancer can be confirmed by collecting a blood sample of a subject and detecting flavin reductase, which is the breast cancer diagnostic marker contained in the blood sample of the subject, using an antibody thereto. .

Therefore, the method for confirming the onset of breast cancer using the flavin reductase of the present invention and the antibody selectively recognizing the same is not only excellent in sensitivity as a new immunological diagnostic tool using the blood of the patient, but also the blood without the biopsy. It can be easily analyzed and can be useful for the early diagnosis of breast cancer.

Accordingly, according to another aspect of the present invention, the present invention provides a breast cancer diagnostic kit comprising an antibody that selectively binds to flavin reductase which is a breast cancer diagnostic marker.

In order to prepare antibodies that selectively bind to flavin reductase marker proteins, the acquisition of flavin reductase must be preceded, which can be synthesized using the amino acid sequence of SEQ ID NO: 1 or produced in microorganisms using genetic recombination. Alternatively, they may be prepared separately from the blood.

For the purposes of the present invention, the antibody may include both polyclonal and monoclonal antibodies of flavin reductase, but monoclonal antibodies capable of more specifically binding to antigens are preferred.

Polyclonal antibodies can be prepared by injecting flavin reductase marker proteins or fragments thereof into an external host with an immunogen according to conventional methods known to those skilled in the art. Examples of such external hosts include mammals such as mice, rats, sheep and rabbits, and immunogens are generally administered by intramuscular, intraperitoneal or subcutaneous injection, together with an adjuvant to increase antigenicity. Is administered to immunize an external host. Serum may be collected periodically from an immunized external host to harvest serum showing enhanced titers and specificity for antigen or antibodies may be isolated and purified from them to prepare polyclonal antibodies specific for flavin reductase.

Monoclonal antibodies can be prepared using methods of generating immortalized cell lines by fusion known to those skilled in the art (Kohler G. et al., Nature , 256: 495-497, 1975). Briefly, the method is first immunized with pure flavin reductase protein or a fragment thereof, or a peptide thereof is synthesized and combined with bovine serum albumin to immunize the mouse. Antibody-producing B lymphocytes isolated from immunized mice are fused with myeloma cells of human or mouse to produce immortalized hybridoma cells. Subsequently, the enzyme immunoassay (ELISA; Enzyme-Linked ImmunoSorbent Assay) was used to investigate the production of monoclonal antibodies in the hybridoma cells. Ascites may be harvested to prepare monoclonal antibodies specific for flavin reductase.

Antibodies used in the detection of the flavin reductase proteins of the invention include functional fragments of antibody molecules as well as complete forms having two full length light chains and two full length heavy chains. A functional fragment of an antibody molecule means a fragment having at least antigen-binding ability, and includes Fab, F (ab '), F (ab') ₂ and Fv.

Breast cancer diagnostic kits of the present invention include not only antibodies that selectively recognize flavin reductase, but also tools, reagents, and the like that are generally used for immunological analysis in the art.

According to one embodiment of the invention, the breast cancer diagnostic kit is an antibody specific for the flavin reductase protein; Secondary antibody conjugates to which a label that is developed by reaction with a substrate is conjugated; A color substrate solution to be colored and reacted with the label; Washing liquid; And it may include a solution for stopping the enzyme reaction.

In addition, the breast cancer diagnostic kit of the present invention may further include a positive control comprising a flavin reductase standard antigen and a negative control comprising an antiserum of an animal not injected with the antigen.

Breast cancer diagnostic kit of the present invention can diagnose breast cancer by quantitatively or qualitatively analyzing the antigen to the antibody protein through an antigen-antibody binding reaction, the antigen-antibody binding reaction is a conventional enzyme immunoassay (ELISA), Radioimmunoassay (RIA), sandwich assay, western blotting, immunoprecipitation, immunohistochemical staining, fluorescence immunoassay, enzyme substrate coloration, antigen-antibody aggregation Can be measured. For example, the diagnostic kit may be provided to perform an ELISA that reacts with a recombinant monoclonal antibody protein using a 96-well microtiter plate or the like coated on a surface of a sample and a control.

As a fixture for antigen-antibody coupling reaction, a nitrocellulose membrane, a PVDF membrane, a well plate synthesized with a polyvinyl resin or a polystyrene resin, a slide glass made of glass, or the like may be used. .

As for the label of the secondary antibody, a conventional color developing agent having a color reaction is preferable, and horseradish peroxidase (HRP), basic alkaline phosphatase, colloid gold, poly L-lysine-fluorescein isothiocyanate (FITC), Labels such as fluorescents such as rhodamine-B-isothiocyanate (RITC) and dyes may be used.

Color substrate to induce color development is preferably used according to the labeling reaction, TMB (3,3 ', 5,5'-tetramethyl bezidine), ABTS [2,2'-azino-bis (3) -ethylbenzothiazoline-6-sulfonic acid), and OPD (o-phenylenediamine) can be used. At this time, the color substrate is more preferably provided in a dissolved state in a buffer solution (0.1 M NaAc, pH 5.5). A chromogenic substrate such as TMB is decomposed by HRP used as a marker of the secondary antibody conjugate to generate a chromosome deposit, and the presence of flavin reductase protein antigen is detected by visually confirming the degree of deposition of the chromosome deposit. .

The wash preferably comprises phosphate buffer, NaCl and Tween 20, more preferably a buffer consisting of 0.02 M phosphate buffer, 0.13 M NaCl, and 0.05% Tween 20 (PBST). The wash solution is washed 3 to 6 times by reacting the secondary antibody to the antigen-antibody conjugate after the antigen-antibody binding reaction, and then adding an appropriate amount to the fixture. As the reaction terminating solution, sulfuric acid solution (H ₂ SO ₄ ) may be preferably used.

In addition, another aspect of the present invention provides a method for detecting flavin reductase, a marker protein for diagnosing breast cancer in a sample using an antigen-antibody binding reaction.

The detection method is immobilized by electrophoresis (SDS-PAGE) of the proteins in the blood and then transferred to the nitrocellulose membrane and contacted with an antibody that selectively recognizes the flavin reductase, and then through the antigen-antibody binding reaction. Indirectly identifying the presence of an empty reductase protein. The antigen-antibody binding reaction includes enzyme immunoassay (ELISA), radioimmunoassay (RIA), sandwich measurement, western blotting, immunoprecipitation, immunohistochemical staining, fluorescence immunoassay, enzyme substrate coloration, and antigen-antibody aggregation. Etc. can be mentioned. Serum or plasma may be used as a sample, and plasma is more preferable.

According to a preferred embodiment of the present invention, the detection method,

1) coating the sample and the protein of the control to the fixture;

2) performing an antigen-antibody binding reaction by adding an antibody specific for flavin reductase to the fixture;

3) detecting the antigen-antibody binding reactant produced through the antigen-antibody binding reaction using a secondary antibody conjugate and a color substrate solution; And

4) comparing the detection results for the sample and the control.

Specifically, the plasma protein is separated from the sample according to the molecular weight. Since the flavin reductase has a molecular weight of approximately 22 kDa, electrophoresis is performed using a 15% polyacrylamide gel, and the proteins separated therefrom are fixed by transferring to a fixture such as a nitrocellulose membrane. Subsequently, an antibody specific for the immobilized protein antigen is added to perform an antigen-antibody binding reaction. If a flavin reductase protein is present in the sample, an antigen-antibody binding reaction occurs when a flavin reductase specific antibody is added to the membrane to which the protein is immobilized. In order to measure the degree of binding of the flavin reductase to the antibody to the antibody, a step of binding to a secondary antibody having an affinity for the flavin reductase antibody is carried out, wherein the horseradish peroxidase (HRP) conjugated to the secondary antibody is a substrate ECL. The presence of flavin reductase protein, which is a diagnostic marker for breast cancer, in the specimens is detected by comparing the extent of the color reaction with enhanced chemiluminescence and the extent of the color reaction.

Meanwhile, biological microchips and automated microorganisms capable of detecting antigens for the antibody proteins by immobilizing an antibody specific for flavin reductase on a biological microchip and then reacting with a sample sample isolated from the subject. Using an microarray system has the advantage of analyzing a large number of samples in one analysis.

Hereinafter, the present invention will be described in more detail with reference to Examples. These examples are only for illustrating the present invention more specifically, but the scope of the present invention is not limited by these examples.

Example  1: Breast Cancer Specific Diagnosis As a marker Flavin  Identification of Reductase

In order to select a diagnostic marker that can be usefully used for the diagnosis of breast cancer due to its specific increase in the blood of breast cancer patients, the present inventors label a protein with a cICAT (cleavable isotope-coded affinity tag) reagent and use a mass spectrometer. Quantitative analysis was used (Gygi SP. Et al., Nat . Biotechnol. , 17: 994-999, 1999). For cICAT quantitative analysis, cICAT reagents (Cat. No. 4339039, Applied Biosystems) consisting of two reagents in which all nine carbon elements were replaced with light isotopes ( ¹² C) or heavy isotopes ( ¹³ C) were used. It was. The cICAT reagent was developed to specifically react with a thiol group.

On the other hand, plasma of six breast cancer patients and plasma of seven non-patients were separately mixed to prepare plasma samples of the breast cancer patient group and the non-patient control group. Multiple affinity removal system (Aglient) to remove relatively high protein albumin, immunoglobulin A, immunoglobulin G, heptoglobin, transferrin and trypsin inhibitors from plasma samples of prepared breast cancer patients and non-patient controls. Liquid chromatography was performed using the column. Protein compartments not bound to the column were collected by tracking with an ultraviolet absorbance of 280 nm and plasma proteins bound to the column were separated and removed. Thus prepared plasma samples were removed through acetone precipitation, and 100 μg of protein samples were prepared from the plasma of breast cancer patients and non-patient controls, respectively. The protein samples of the breast cancer patient group were added with 3.5 mM heavy cICAT reagent, and the protein samples of the non-patient control group were added with 3.5 mM light cICAT reagent and reacted for 120 minutes at 37 ° C for labeling. Each protein sample labeled with cICAT reagent was mixed in equal proportions, followed by adding 25 μl of 5 μg trypsin, equivalent to 1/40 of 200 μg total protein, and treating it for 16 hours at 37 ° C. Separated. The peptide fragment thus obtained was loaded on a strong cation exchange resin column, eluted through a potassium chloride concentration gradient (0% → 60%), and divided into several fractions. Sixteen fractions obtained through cation exchange resin column chromatography were packed in an avidin affinity column to concentrate only the peptide to which the cICAT reagent was bound. The resulting sample was treated with phosphoric acid to remove biotin conjugated to cICAT reagents, thereby preparing a final sample for mass spectrometry.

The final sample prepared above was subjected to reverse phase resin chromatography to separate plasma peptide fragments, and a tandem mass spectrometry of each fragment was obtained using a tandem mass spectrometer. At this time, reverse phase chromatography is a column filled with a magic aqua resin (magic C18 aqua resin, Microchom) in a silica coated capillary with an inner diameter of 75 μm and acetonitrile concentration of 5% to 40% for 70 minutes. It was carried out using a gradient. Proteins were identified by comparing the tandem mass spectrometry information of peptide fragments with the SWISS-PROT protein database using the SEQUEST computer analysis program (Thermofinnigan) and reconfirmed proteins identified using the ISB pipeline (Institute for Systems Biology). From this, the quantitative differences between breast cancer patients and non-patient control samples were analyzed (Keller A. et al, Anal . Chem ., 15: 5395-5392, 2002; Nesvizhskii AI. Et al., Anal . Chem ., 75 : 4646-4658, 2003; Li X J. et al., Anal. Chem ., 75: 6648-6657, 2003).

Since proteins in plasma samples from non-patient controls are labeled with light cICAT reagents and proteins in plasma samples from breast cancer patient groups are labeled with heavy cICAT reagents, peptides with the same amino acid sequence from the same protein also show mass differences. Thus, the peptide used to identify one protein may be a peptide labeled with a light cICAT reagent or may be a peptide labeled with a heavy cICAT reagent. The chromatograms of each of the peptides labeled with the light and heavy cICAT reagents used for identification of specific proteins were traced to calculate their mass peak area and the chromatogram area ratio of each peptide was calculated. The difference in protein expression can be quantified between the cancer and breast cancer patients. From these quantitative analyzes, tryptic peptides with an increased expression level were specifically selected in the breast cancer patient group compared to the non-patient control group and confirmed that the peptide has an amino acid sequence represented by SEQ ID NO: 2 .

1 is a breast cancer in which a cysteine residue is labeled with a light cICAT reagent (C ⁺ ) and a cysteine residue is labeled with a heavy cICAT reagent (C ^* ) in the amino acid sequence of the peptide of SEQ ID NO: 2 selected above. Based on traces of patient-derived peptides, the area of the chromatogram of each peptide labeled with a light cICAT reagent and a heavy cICAT reagent increased by 3.48-fold in the breast cancer patient group compared to the non-patient control group. It was confirmed. 2A and 2B show tandem mass spectrometry results of the peptide of SEQ ID NO: 2 , in which the amount of expression in the blood of the breast cancer patient group specifically increased, wherein the protein identified by the mass spectrometer was sequenced It was confirmed that it is a flavin reductase protein having an amino acid sequence of No. 1 .

Example  2: Immunoblotting  Used In the blood Flavin  Reductase Detection

In order to confirm whether the flavin reductase protein of SEQ ID NO: 1 identified in Example 1 can be used as a marker for the selective diagnosis of breast cancer in the blood, immunoblotting was performed as follows.

First, take 30 μl of plasma from 6 breast cancer patients and 7 non-patient controls, and remove albumin, immunoglobulin A, immunoglobulin G, heptoglobin, transferrin, trypsin inhibitors, etc. In order to perform the chromatography equipped with MARS (Aligent) column. Protein compartments not bound to the column were collected by tracking with an ultraviolet absorbance of 280 nm, and blood proteins bound to the column were separated and removed. Thus, only proteins having a size of 3 kDa or more were collected and concentrated from the blood protein-removed compartment to prepare plasma protein samples of the breast cancer patient group and the non-patient control group. 5 μg of each of the prepared plasma protein samples and a buffer solution containing 1% SDS were mixed, followed by electrophoresis using 15% SDS polyacrylamide gel. The separated serum proteins were transferred to nitrocellulose membranes in a solution containing 25 mM Tris-HCl, 190 mM glycine and 10% methanol and the transferred membranes contained 5% skim milk powder. The reaction was carried out in TBST (Tris-buffered saline Tween 20) for 1 hour.

Subsequently, the nitrocellulose membrane was reacted with an anti-flavin reductase antibody (1: 1000, Abnova) for 16 hours at 4 ° C., washed three times with TBST, and then mouse IgG-HRP (1). : 2000, Amersham Bioscience) and the reaction at 25 ℃ for 1 hour. Thereafter, the nitrocellulose membrane was reacted with ECL (enhanced chemiluminescence, Amersham Bioscience, Inc.) and then subjected to X-ray film to measure the concentration of flavin reductase antigen.

FIG. 3 shows the results of immunoblotting with an anti-flavin reductase antibody after analyzing the plasma of the non-patient control group and the plasma of the breast cancer patient group by electrophoresis, and FIG. 4 shows the immunoblotting of FIG . The concentration of antigen measured by the graph is shown. As shown in Figures 3 and 4, in the case of breast cancer patients, the concentration of flavin reductase protein in blood tended to be 3.1 times higher than that of normal people. From these results, antibodies that selectively recognize flavin reductase in blood By measuring the concentration of the antigen using and comparing it with the non-patient control, it was confirmed that a test subject showing a relatively increased concentration of flavin reductase protein can be diagnosed as a breast cancer patient.

As described above, the breast cancer diagnostic kit using the marker protein for diagnosing breast cancer of the present invention and an antibody thereof has a burden on a patient unlike a conventional breast cancer diagnosis method for biopsy because blood samples are relatively easy to collect. Not only can breast cancer be diagnosed very easily, but also the accuracy and sensitivity of the diagnosis can be useful for early diagnosis of breast cancer.

<110> Korea Institute of Science and Technology <120> PROTEIN MARKER FLAVIN REDUCTASE FOR BREAST CANCER DIAGNOSIS AND          DIAGNOSIS KIT FOR BREAST CANCER USING ANTIBODY AGAINST THE SAME <130> KC071050 <160> 2 <170> KopatentIn 1.71 <210> 1 <211> 205 <212> PRT <213> human flavin reductase protein <400> 1 Ala Val Lys Lys Ile Ala Ile Phe Gly Ala Thr Gly Gln Thr Gly Leu   1 5 10 15 Thr Thr Leu Ala Gln Ala Val Gln Ala Gly Tyr Glu Val Thr Val Leu              20 25 30 Val Arg Asp Ser Ser Arg Leu Pro Ser Glu Gly Pro Arg Pro Ala His          35 40 45 Val Val Val Gly Asp Val Leu Gln Ala Ala Asp Val Asp Lys Thr Val      50 55 60 Ala Gly Gln Asp Ala Val Ile Val Leu Leu Gly Thr Arg Asn Asp Leu  65 70 75 80 Ser Pro Thr Thr Val Met Ser Glu Gly Ala Arg Asn Ile Val Ala Ala                  85 90 95 Met Lys Ala His Gly Val Asp Lys Val Val Ala Cys Thr Ser Ala Phe             100 105 110 Leu Leu Trp Asp Pro Thr Lys Val Pro Pro Arg Leu Gln Ala Val Thr         115 120 125 Asp Asp His Ile Arg Met His Lys Val Leu Arg Glu Ser Gly Leu Lys     130 135 140 Tyr Val Ala Val Met Pro Pro His Ile Gly Asp Gln Pro Leu Thr Gly 145 150 155 160 Ala Tyr Thr Val Thr Leu Asp Gly Arg Gly Pro Ser Arg Val Ile Ser                 165 170 175 Lys His Asp Leu Gly His Phe Met Leu Arg Cys Leu Thr Thr Asp Glu             180 185 190 Tyr Asp Gly His Ser Thr Tyr Pro Ser His Gln Tyr Gln         195 200 205 <210> 2 <211> 19 <212> PRT <213> Artificial Sequence <220> <223> tryptic peptide <400> 2 Cys Leu Thr Thr Asp Glu Tyr Asp Gly His Ser Thr Tyr Pro Ser His   1 5 10 15 Gln Tyr Gln              

Claims (12)

A breast cancer diagnostic kit comprising an antibody specific for a flavin reductase protein marker having an amino acid sequence of SEQ ID NO: 1 . The method of claim 1, Breast cancer diagnostic kit, characterized in that the antibody is a polyclonal antibody or a monoclonal antibody. The method of claim 1, Secondary antibody conjugates to which a label that is developed by reaction with a substrate is conjugated; A color substrate solution to be colored and reacted with the label; Washing liquid; And a breast cancer diagnostic kit further comprises an enzyme reaction stopper. The method of claim 3, Diagnostic kit characterized in that the label of the secondary antibody conjugate is selected from the group consisting of horseradish peroxidase (HRP), basic alkaline phosphatase, colloid gold, fluorescent (fluorescein) and dye (dye) . The method of claim 3, Group consisting of TMB (3,3 ', 5,5'-tetramethyl bezidine), ABTS [2,2'-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid)] and OPD (o-phenylenediamine) The diagnostic kit, characterized in that selected from. A method for detecting flavin reductase protein markers from an object using an antigen-antibody binding reaction. The method of claim 6, 1) coating the sample and the protein of the control to the fixture; 2) performing an antigen-antibody binding reaction by adding an antibody specific for flavin reductase to the fixture; 3) detecting the antigen-antibody binding reactant produced through the antigen-antibody binding reaction using a secondary antibody conjugate and a color substrate solution; And 4) comparing the detection results for the sample and the control. The method of claim 7, wherein The sample of step 1) is characterized in that the serum or plasma. The method of claim 7, wherein The fixture of step 1) is selected from the group consisting of nitrocellulose membranes, PVDF membranes, well plates synthesized from polyvinyl or polystyrene resins and slide glass of glass. The method of claim 7, wherein The antigen-antibody binding reaction of step 2) is performed by enzyme-linked immunosorbent assay (ELISA), radioimmuno assay (RIA), sandwich assay, western blotting, immunoprecipitation method, immune tissue Immunohistochemical staining (Immnohistochemical staining), fluorescence immunoassay, enzyme substrate coloration, antigen-antibody aggregation method characterized in that it is selected from the group consisting of. The method of claim 7, wherein The label of the secondary antibody conjugate of step 3) is selected from the group consisting of HRP, basic dephosphatase, colloidal gold, fluorescent substance and pigment. The method of claim 7, wherein The chromogenic substrate of step 3) is selected from the group consisting of TMB, ABTS and OPD.

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