JPH09189702A - Method for measuring antimucin antibody, cancer measuring method, and cancer diagnostic medicine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively detect a cancer by forming a mucin peptides-antimucin antibody complex by bringing a specimen into contact with mucin peptides and measuring the complex. SOLUTION: A mucin peptides-antimucin antibody complex is formed by bonding an antimucin antibody contained in a specimen to mucin peptides through an antigen-antibody reaction caused by bringing the specimen into contact with the mucin peptides by mixing the specimen in the mucin peptides. At the time of measuring the complex, an immunoassay method in which the antimucin antibody contained in the specimen is measured by utilizing an antibody labeled with, for example, an enzyme, radioisotope, etc., or an agglutination method in which the variation of the turbidity or absorbance of the specimen caused by the formation of the complex, etc., is measured can be utilized. The serum, etc., of a patient can be utilized as the specimen and a phosphoric acid buffer solution containing a surface activate agent can be utilized as a cleaning solution. This measuring method using the antimucin antibody can be effectively utilized for the measurement of cancer.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for measuring anti-mucin antibody, a method for measuring cancer, and a diagnostic agent for cancer.

[0002]

2. Description of the Related Art Mucin is a glycoprotein that is synthesized in large amounts in adenocarcinoma and the like, but is also synthesized in normal cells (Zotter S et al., Cancer Review, 11-12, 55-).
101 pages (1988) (Zotter, S. et al., Cancer Rev., Vo
l.11-12, p.55-101 (1988))). So far, preparation of a mouse monoclonal antibody against mucin and an amino acid sequence recognized by the monoclonal antibody have been reported (Taylor-Papadimitriou Jay et al., International Journal of Cancer, 28, 17).
-21 (1981) (Taylor-Papadimitriou J. et al., In
tJCancer, Vol.28, p.17-21 (1981))). Then, a method for diagnosing cancer by measuring mucin itself as a cancer marker using a mouse monoclonal antibody against mucin has been reported (His DEF et al., Journal of Clinical Investigation. , 75, 1397-1402 (1985) (Hayes, DF et
al., J. Clin. Invest., Vol.75, p.1397-1402 (198
Five))). However, this method has a problem that a positive rate to such an extent that cancer can be accurately diagnosed cannot be obtained, and that a subject may be misdiagnosed as negative despite having cancer.

[0003]

The invention according to claim 1 provides a method for measuring an anti-mucin antibody useful for detecting and measuring cancer. The inventions according to claims 2, 3, 4 and 5 provide a method for measuring cancer, which is effective in diagnosing whether a subject has cancer. The inventions of claims 6, 7 and 8 provide a cancer diagnostic agent effective for diagnosing whether or not a subject has cancer.

[0004]

Means for Solving the Problems The present invention includes the following (1) to
Regarding (8). (1) A method for measuring anti-mucin antibody, which comprises contacting a sample with mucin peptides to form a mucin peptide-anti-mucin antibody complex, and measuring the complex. (2) A method for measuring cancer, which comprises measuring an anti-mucin antibody present in a sample. (3) The method for measuring cancer according to (2) above, which comprises the step of contacting a sample with mucin peptides to form a mucin peptide-anti-mucin antibody complex, and measuring the complex. (4) The method for measuring cancer according to (3) above, wherein the mucin peptides are peptides containing a sequence consisting of at least 5 consecutive amino acids in the peptide represented by SEQ ID NO: 1.

(5) The mucin peptides are SEQ ID NOs: 1 to
The method for measuring cancer according to (3) or (4) above, which is a peptide represented by any one of 4 above. (6) A cancer diagnostic agent comprising mucin peptides as an active ingredient. (7) The cancer diagnostic agent according to (6) above, wherein the mucin peptides are peptides containing a sequence consisting of at least 5 consecutive amino acids in the peptide represented by SEQ ID NO: 1. (8) The cancer diagnostic agent according to (6) or (7) above, wherein the mucin peptides are peptides represented by any of SEQ ID NOS: 1 to 4.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. Mucin Mucin is a glycoprotein as described above, and human mucin has the amino acid sequence of the peptide represented by SEQ ID NO: 1 (Lancaster C. A. et al., Biochemical Biophysical Research Communication, Vol. 173, 1019-1029 (1990) (Lancaster, CA e
t al., Biochem. Biophys. Res. Commun., Vol.173, p.1
019-1029 (1990))). In the sequence listing, the amino acid sequence has the amino acid at the terminal amino group as number 1 (the same applies hereinafter).

Mucin peptides In the present invention, mucin peptides are a generic name for mucin, a part thereof, or a peptide containing mucin or a part thereof, and organic compounds other than amino acids (lipid, carboxylic acid, aminocarboxylic acid) in the peptide chain. Residues, etc.). The above-mentioned mucin peptides are required to be able to serve as an antigen for anti-mucin antibodies present in a sample, that is, to possess antigenicity as mucin.

[0008] From the viewpoint of the minimum size of mucin having antigenicity, mucin peptides are peptides containing a sequence consisting of at least 5 consecutive amino acids in the peptide shown in SEQ ID NO: 1 (hereinafter referred to as peptide A). Is preferred). The sequence consisting of at least 5 consecutive amino acids in the peptide represented by SEQ ID NO: 1 includes, for example, the amino acid sequence of the peptide represented by SEQ ID NO: 4, and this peptide is also an example of peptide A. This amino acid sequence is an amino acid sequence of an epitope recognized by a murine monoclonal antibody against mucin, and possesses antigenicity as mucin.

[0009] Since a longer mucin-derived amino acid sequence contained in the peptide chain of mucin peptides can be expected for a highly sensitive antigen-antibody reaction, peptide A is among the peptides shown in SEQ ID NO: 1. It is preferably a peptide containing a sequence consisting of 20 or more consecutive amino acids. Such peptides include:
For example, the peptide represented by SEQ ID NO: 2 can be mentioned.
This peptide is a fragment of human mucin and possesses the antigenicity as mucin.

From the viewpoint of enhancing the antigenicity, the peptide A is preferably a peptide having a sequence in which a sequence consisting of at least 5 consecutive amino acids in the peptide represented by SEQ ID NO: 1 is repeated. . The sequence serving as the repeating unit is, for example, SEQ ID NO: 2 described above.
The amino acid sequence of the peptide represented by The number of repetitions is not particularly limited, but is usually 1 to 10 times. The repeating units are bound to each other directly or via an intervening substance. Examples of the inclusions include amino acid sequences and organic compounds other than amino acid residues. The number of amino acids contained in the amino acid sequence is not particularly limited, but is usually 1 to 50, and specific examples of the amino acid sequence include an amino acid sequence consisting of alanine-alanine-alanine. Moreover, examples of the organic compound include residues such as lipids, carboxylic acids, and aminocarboxylic acids. The number of carbon atoms in the organic compound is not particularly limited, but is usually 1 to 100,
Specific examples of the organic compound include stearic acid residues.

Examples of such a peptide include the peptide shown in SEQ ID NO: 3. This peptide is a peptide containing a sequence of 63 amino acids in which alanine-alanine-alanine is bound to the amino group terminal side of a peptide containing 3 repeating units consisting of the peptide of SEQ ID NO: 2, which is an antigen as mucin. Possesses sex and is highly antigenic. The alanine-alanine-alanine is a spacer for immobilizing a peptide containing three repeating units on a carrier.

The peptide A may be a peptide lacking amino acids (for example, 1 to 462) from the peptide shown in SEQ ID NO: 1 as long as it retains the antigenicity as mucin. If too many amino acids are missing,
The antigenicity of peptide A as mucin tends to be impaired. When the number of missing amino acids is large (for example, 5 or more), the antigenicity of mucin is likely to decrease. Therefore, in order to minimize this decrease, the amino acids missing from the peptide represented by SEQ ID NO: 1 are consecutive. It is preferable that the

Further, as long as the mucin has the antigenicity, a peptide containing an amino acid sequence other than the amino acid sequence derived from mucin can be used as the peptide A. It is required that the antigenicity as a compound other than mucin is low or low. Examples of such peptides include a peptide in which an amino acid in the peptide represented by SEQ ID NO: 1 is replaced with another amino acid, a peptide in which an amino acid is inserted in the peptide represented by SEQ ID NO: 1, a sequence Examples include a peptide in which an amino acid or another peptide is bound to a sequence consisting of at least 5 consecutive amino acids in the peptide represented by No. 1 directly or via an intervening substance.

When the number of amino acids to be substituted or inserted is large (for example, 5 or more), and when the number of amino acids contained in other peptides to be bound is too large (for example, 1,
000 or more), the antigenicity of mucin is likely to decrease. Therefore, in order to reduce this decrease as much as possible, the amino acids substituted or inserted in the peptide represented by SEQ ID NO: 1 are consecutive. Preferably, the other peptide to be bound is preferably a sequence consisting of less than 1,000 amino acids. The amino acids to be substituted preferably have similar properties, and include, for example, substitution of glycine for alanine. Amino acids or other peptides that bind are:
For example, alanine, alanine-alanine-alanine, β
-Galactosidase and the like. As inclusions,
The ones mentioned above can be mentioned. The inclusion, amino acid or other peptide may be bound to either the amino group terminal side or the carboxyl group terminal side of the sequence consisting of at least 5 consecutive amino acids in the peptide shown in SEQ ID NO: 1. .

Method for producing mucin peptides Examples of the method for producing the mucin peptides in the present invention include a chemical synthesis method and a gene recombination method. Examples of the chemical synthesis method include 9-fluorenylmethyloxycarbonyl (Fmoc) solid-phase synthesis method,
A commercially available peptide synthesizer can be used. This method is described in "Atherton E. et al., Solid phase peptide synthesis a practical approach, IR El Press, Oxford (1989) (Athrton E. et al., Solid phase peptide
synthesis a practical approach, IRL Press, Oxford
(1989)) ”.

As a gene recombination method, for example, a DNA encoding the mucin peptides of the present invention is inserted into a vector to construct a recombinant vector, which is inserted into a host to prepare a transformant. There is a method of purifying the target peptide from the transformant. As the DNA encoding the mucin peptides in the present invention, for example, DNA encoding the amino acid sequence of the peptide shown in SEQ ID NO: 1 can be mentioned. Examples of the vector include plasmids and phages. Examples of the host include Escherichia coli, Bacillus subtilis, yeast and the like.

Anti-mucin antibody measuring method and cancer measuring method As the anti-mucin antibody measuring method, for example, a mucin peptide is contacted with a sample to form a mucin peptide-anti-mucin antibody complex, and the complex Can be used. As a method of contacting the sample with the mucin peptides, for example, a method of mixing the sample with the mucin peptides can be used.

The mucin peptides-anti-mucin antibody complex is a compound in which the mucin peptides are bound to the anti-mucin antibody in the sample by an antigen-antibody reaction. As a method for measuring this complex, for example, an antibody labeled with a label is used, and the anti-mucin antibody in a sample is measured using the label (immunoassay), mucin peptides-anti A method of measuring changes in turbidity or absorbance of a sample based on the formation of a mucin antibody complex (aggregation method) and the like can be used. As the immunoassay, an enzyme immunoassay in which the label is an enzyme, a radioimmunoassay in which the label is a radioisotope, and the like can be used. In the present invention,
“Measurement” includes not only quantitative measurement but also qualitative measurement such as “detection”.

As a method for measuring an anti-mucin antibody using an enzyme immunoassay, for example, the above-mentioned mucin peptides are immobilized on a carrier, a sample is added to the carrier, and the enzyme is labeled with a secondary antibody. It is possible to use a method of adding, washing, adding a substrate, reacting the enzyme with the substrate, and measuring luminescence, color development and the like due to the reaction. As the carrier, for example, a microtiter plate or latex particles can be used. Examples of the method for immobilizing mucin peptides on a carrier include a binding method using biotin and avidin (or streptavidin).
A general method for immobilizing a peptide or the like using biotin and avidin (or streptavidin) is, for example,
"Eiji Ishikawa, Ultrasensitive enzyme immunoassay, Academic Publishing Center, 1993".

As the sample, for example, serum of a subject can be used. As the washing liquid used for washing, for example, a phosphate buffer containing a surfactant can be used. As the phosphate buffer, Dulbecco's PBS (−) can be used, for example. As the enzyme-labeled secondary antibody, for example, goat anti-human immunoglobulin antibody and the like can be used, and such antibody can be purchased from, for example, PIERCE. As the substrate, for example, when the enzyme is peroxidase, 3,3 ′, 5,5′-tetramethylbenzidine (manufactured by Sigma, trade name: TMB) can be used.

As a method for measuring cancer, for example, the serum of a healthy person and the serum of a subject are used as serum, and the anti-mucin antibody is measured as described above, and the method of comparing the results is used. You can The serum of a healthy person contains a large amount of anti-mucin antibody. Therefore, when the serum of a healthy person is used, the titer (antibody titer) of the anti-mucin antibody tends to increase. However, the amount of anti-mucin antibody contained in the serum of cancer patients is smaller than that in the serum of healthy individuals. Therefore, when serum of a cancer patient is used, the titer (antibody titer) of the anti-mucin antibody tends to be low. Therefore, when the antibody titer of the anti-mucin antibody obtained using the serum of the subject is lower than the antibody titer of the anti-mucin antibody obtained using the serum of a healthy person, the subject has cancer. Can be diagnosed as possible. In order to correct the physiological disparity between healthy individuals, it is preferable to use as many healthy individuals as possible and determine the antibody titer range of the anti-mucin antibody in the healthy individuals. Moreover, when diagnosing whether or not cancer is actually present, it is preferable to use it in combination with other known cancer diagnosis methods, and to make a diagnosis after considering the results thereof.

Cancer Diagnostic Agent The cancer diagnostic agent of the present invention contains the above-mentioned mucin peptides as an active ingredient, and examples thereof include a carrier on which the above-mentioned mucin peptides are immobilized. To the enzyme-labeled secondary antibody, the substrate, a preservative, a stabilizer,
A kit including a sensitizer and the like may also be included. The cancer diagnostic agent of the present invention includes, for example, ovarian cancer, breast cancer, colon cancer, gastric cancer,
It can be used for diagnosis of lung cancer. The cancer diagnostic agent of the present invention can also be used as a marker for examining the presence or absence of cancer metastasis after surgery.

[0023]

The present invention will be described in detail below with reference to examples. Example 1 Synthesis of mucin peptides Since the amino acid sequence of the epitope recognized by the mouse monoclonal antibody against mucin is the amino acid sequence of the peptide represented by SEQ ID NO: 4, the amino acid sequence of the mucin peptides containing this amino acid sequence is: First,
The amino acid sequence of the peptide represented by SEQ ID NO: 2 was designed. Furthermore, the amino acid sequence of the peptide represented by SEQ ID NO: 3 is an amino acid sequence of mucin peptides in which this amino acid sequence is repeated three times and an amino acid sequence consisting of alanine-alanine-alanine is present on the amino group terminal side as a spacer. Designed. According to the 9-fluorenylmethyloxycarbonyl (Fmoc) solid-phase synthesis method, Millipore 9050 plus pepsin synthesizer (Mi
llipore 9050 plus pepsynthesizer) (Millipore (Mill
The mucin peptides having the amino acid sequence of the peptide represented by SEQ ID NO: 3 (however, the amino group terminal side is biotinylated) were synthesized by using ipore) (trade name).

1.0 g of 9-fluorenylmethyloxycarbonyl-glycine-polyethylene glycol-polystyrene (Fmoc-Gly-PEG-PS) (support substitution rate: 0.2 miliequivalent)
/ G) as a starting material and each Fmoc amino acid
A 4-fold molar amount of -Gly-PEG-PS was added and reacted. Activation of the carboxyl terminal at the time of peptide synthesis is
Diisopropylcarbonyldiimidazole (DIPCD
It was carried out with a mixture of I) and hydroxybenzotriazole (HOBt). To the obtained mucin peptides, 0.1 g of biotin previously dissolved in 1 g of dimethyl sulfoxide (DMSO) was added, and the amino group terminal side of the obtained mucin peptides was biotinylated.

Example 2 Measurement of antibody titer of anti-mucin antibody (1) Immobilization of mucin peptides Dulbecco P containing 0.02% (w / v) of sodium azide
BS (-), 4μ of streptavidin (manufactured by Sigma)
g / ml was dissolved, and the obtained solution was dispensed into a microtiter plate (Nunc Co., Ltd.) in an amount of 75 μl / well (well for injecting the sample in the plate) and allowed to stand still at 4 ° C. overnight I put it. Dulbecco PBS (-)
The used was Dulbecco's PBS (-) "Nissui" (trade name, manufactured by Nissui Pharmaceutical Co., Ltd.).

After standing, the solution in the wells was removed by suction, and the wells were washed with 200 μl of Dulbecco's PBS (−) per well, and this washing operation was repeated twice.
Next, PBS (-) containing 1% (w / v) bovine serum albumin and 0.02% (w / v) sodium azide was added,
300 μl was dispensed per well and left at 37 ° C. for 30 minutes. After removing the solution in the well by suction, Tween2
Dulbecco's PBS containing 0.005% (v / v)
The wells were washed with 250 μl of (−) per well (hereinafter, this operation is abbreviated as PBS (−) T washing operation),
This PBS (-) T washing operation was performed once more. Dulbecco's PBS containing 1% bovine serum albumin (w / v), 0.02% sodium azide (w / v) and 2.5 mg / ml of the mucin peptides synthesized in Example 1.
(-) Was dispensed at 100 µl per well, left at room temperature for 24 hours, and the solution in the well was removed by suction.
The (-) T washing operation was performed 3 times.

(2) Addition of serum (containing anti-mucin antibody (primary antibody)) Dulbecco's PBS (-) containing 1% (w / v) bovine serum albumin and 0.02% (w / v) sodium azide. Was used to dilute the serum of a healthy person or an ovarian cancer patient 500-fold. The diluted serum was dispensed in an amount of 100 μl per well, allowed to stand overnight at 4 ° C., and washed with PBS (−) T seven times.

(3) Addition of enzyme-labeled secondary antibody and color development reaction Peroxidase-labeled goat anti-human immunoglobulin antibody (PIERCE) was added to Dulbecco's PBS (-) containing 1% (w / v) bovine serum albumin. Diluted 1000 times with 100 μl per well, and left still at room temperature for 2 hours. Then, the solution in the well is removed by suction, and PB
The S (-) T washing operation was performed 7 times. Then, 100 μl of distilled water was dispensed per well and removed by suction. TM
A solution of 1 tablet of B (trade name, manufactured by Sigma), 1 ml of dimethyl sulfoxide, and 2 μl of hydrogen peroxide in 9 ml of 0.2M phosphate citrate buffer (pH 5.0) was prepared, and 200 μl per well was prepared. Was dispensed and allowed to stand for 10 minutes at room temperature to cause color reaction. Then, 100 μl of 2M sulfuric acid was added to each well to stop the color development reaction, and the absorbance of the solution in the well at 450 nm was measured to obtain the antibody titer.

(4) Measurement Results The antibody titers obtained using the sera of 10 healthy subjects and 32 ovarian cancer patients are shown in Table 1, Table 2, Table 3 and Table 4, respectively.
Shown in The mean ± standard deviation of antibody titers in healthy subjects is 0.31
It was 5 ± 0.053. On the other hand, the average ± standard deviation of the antibody titers of the ovarian cancer patients was 0.200 ± 0.053, and the antibody titers of the ovarian cancer patients were significantly lower than those of the healthy subjects. From this, it became clear that ovarian cancer can be diagnosed by measuring the antibody titer of the anti-mucin antibody.

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

[Table 3]

[0033]

[Table 4]

[0034]

The method for measuring anti-mucin antibody according to claim 1 is useful for measuring cancer. The method for measuring cancer according to claims 2, 3, 4 and 5 is effective for diagnosing whether the subject has cancer. The cancer diagnostic agents according to claims 6, 7 and 8 are effective in diagnosing whether a subject has cancer.

[0035]

[Sequence list]

 SEQ ID NO: 1 Sequence length: 467 Sequence type: Amino acid Sequence type: Peptide sequence Met Thr Pro Gly Thr Gln Ser Pro Phe Phe Leu Leu Leu Leu Leu Thr 1 5 10 15 Val Ler Thr Val Val Thr Gly Ser Gly His Ala Ser Ser Thr Pro Gly 20 25 30 Gly Glu Lys Glu Thr Ser Ala Thr Gln Arg Ser Val Pro Ser Ser Thr 35 40 45 Glu Lys Asn Ala Val Ser Met Thr Ser Ser Val Leu Ser Ser His Ser 50 55 60 Pro Gly Ser Gly Ser Ser Thr Thr Gln Gly Gln Asp Val Thr Leu Ala 65 70 75 80 Pro Ala Thr Glu Pro Ala Ser Gly Ser Ala Ala Thr Trp Gly Gln Asp 85 90 95 Val Thr Ser Val Val Thr Arg Pro Ala Leu Gly Ser Thr Thr Pro Pro 100 105 110 Ala His Asp Val Thr Ser Ala Pro Asp Asn Lys Pro Ala Pro Gly Ser 115 120 125 Thr Ala Pro Pro Ala His Gly Val Thr Ser Ala Pro Asp Thr Arg Pro 130 135 140 Ala Pro Gly Ser Thr Ala Pro Pro Ala His Gly Val Thr Ala Pro Asp 145 150 155 160 Asn Arg Thr Ala Leu Gly Ser Thr Ala Pro Pro Val His Asn Val Thr 165 170 175 Ser Ala Ser Gly Ser Ala Ser Gly Ser Ala Ser Thr Leu Val His Asn 180 1 85 190 Gly Thr Ser Ala Arg Ala Thr Thr Thr Pro Ala Ser Lys Ser Thr Pro 195 200 205 Phe Ser Thr Pro Ser His Ser Asp Thr Pro Thr Thr Leu Ala Ser His 210 215 220 Ser Thr Lys Thr Asp Ala Ser Ser Thr His His Ser Thr Val Pro Pro 225 230 235 240 Leu Thr Ser Ser Asn His Ser Thr Ser Pro Gln Leu Ser Thr Gly Val 245 250 255 Ser Phe Phe Phe Leu Ser Phe His Ile Ser Asn Leu Gln Phe Asn Ser 260 265 270 Leu Glu Asp Pro Ser Thr Asp Trp Tyr Gln Glu Leu Gln Arg Asp Ile 275 280 285 Ser Glu Met Phe Leu Gln Ilu Tyr Lys Gln Gly Gly Phe Leu Gly Leu 290 295 300 Ser Asn Ile Lys Phe Arg Pro Gly Ser Val Val Val Gln Leu Thr Leu 305 310 315 320 Ala Phe Arg Glu Gly Thr Ile Asn His Asp Val Glu Thr Gln Phe Asn 325 330 335 Gln Tyr Lys Thr Glu Ala Ala Ser Thr Tyr Asn Leu Thr Ile Ser Asp 340 345 350 Val Ser Val Ser Asp Val Pro Phe Pro Phe Ser Ala Gln Ser Gly Ala 355 360 365 Gly Val Pro Gly Trp Gly Ile Ala Leu Leu Val Leu Val Cys Val Leu 370 375 380 Val Leu Ala Ile Val Tyr Leu Ile Ala Leu Ala Val Cys Gln Cys Arg 385 390 3 95 400 Arg Lys Asn Tyr Gly Gln Leu Asp Ile Phe Pro Ala Arg Asp Thr Tyr 405 410 415 His Pro Met Ser Glu Tyr Pro Thr Tyr His Thr His Gly Arg Tyr Val 420 425 430 Pro Pro Ser Ser Thr Asp Arg Ser Pro Tyr Lys Val Ser Ala Gly Asn 435 440 445 Gly Gly Ser Ser Leu Ser Tyr Thr Asn Pro Ala Val Ala Ala Thr Ser 450 455 460 Ala Asn Leu 465 467

SEQ ID NO: 2 Sequence length: 20 Sequence type: Amino acid Sequence type: Peptide sequence Val Thr Ser Ala Pro Asp Thr Arg Pro Ala Pro Gly Ser Thr Ala Pro 1 5 10 15 Pro Ala His Gly20

SEQ ID NO: 3 Sequence length: 63 Sequence type: Amino acid Sequence type: Peptide sequence Ala Ala Ala Val Thr Ser Ala Pro Asp Thr Arg Pro Ala Pro Gly Ser 1 5 10 15 Thr Ala Pro Pro Ala His Gly Val Thr Ser Ala Pro Asp Thr Arg Pro 20 25 30 Ala Pro Gly Ser Thr Ala Pro Pro Ala His Gly Val Thr Ser Ala Pro 35 40 45 Asp Thr Arg Pro Ala Pro Gly Ser Thr Ala Pro Pro Ala His Gly 50 55 60 63

SEQ ID NO: 4 Sequence length: 5 Sequence type: Amino acid Sequence type: Peptide

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshiki Nakao 4-13-1, Higashimachi, Hitachi-shi, Ibaraki Hitachi Chemical Co., Ltd. Pharmaceutical Research Laboratory

Claims (8)

[Claims] 1. A method for measuring an anti-mucin antibody, which comprises contacting a sample with mucin peptides to form a mucin peptide-anti-mucin antibody complex, and measuring the complex. 2. A method for measuring cancer, which comprises measuring an anti-mucin antibody present in a sample. 3. The method for measuring cancer according to claim 2, comprising the step of contacting a sample with mucin peptides to form a mucin peptide-anti-mucin antibody complex, and measuring the complex. 4. The method for measuring cancer according to claim 3, wherein the mucin peptides are peptides containing a sequence consisting of at least 5 consecutive amino acids in the peptide represented by SEQ ID NO: 1. 5. The method for measuring cancer according to claim 3 or 4, wherein the mucin peptides are peptides represented by any of SEQ ID NOS: 1 to 4. 6. A cancer diagnostic agent comprising mucin peptides as an active ingredient. 7. The cancer diagnostic agent according to claim 6, wherein the mucin peptides are peptides containing a sequence consisting of at least 5 consecutive amino acids in the peptide represented by SEQ ID NO: 1. 8. The cancer diagnostic agent according to claim 6 or 7, wherein the mucin peptides are peptides represented by any of SEQ ID NOs: 1 to 4.