Biomarker for detecting cancer
Methods for detecting colorectal cancer in a subject by detection of a galactose-containing 40 kDa molecule in a serum sample from the subject. Methods for quantifying the amount of a galactose-containing molecule in a serum sample are also provided.
1. A method of treating a subject having colorectal cancer or pre-cancer comprising performing a colonoscopy on the subject after having been determined to have a colorectal cancer or pre-cancer, said method comprising the following steps:
(a) desialylating a serum sample from the subject; and then
(b) contacting the desialylated serum sample with an antibody that binds haptoglobin to form a complex; and then
(c) quantitating the complex with a detectable lectin that binds galactose in order to detect or diagnose colorectal cancer using a quantitative immune-detection assay, wherein the presence of a galactose-containing haptoglobin glycoform is associated with the presence of colorectal cancer, wherein the quantitative immune-detection assay is not a Western blot; and then
(d) performing a colonoscopy on the subject.
2. The method of claim 1 , wherein the detectable lectin that binds galactose is selected from the group consisting of Ricinus communis lectin, Sophora japonica lectin, Datura stramonium lectin, Erythrina cristagalli lectin, and Lycopersicon esculentum lectin.
3. The method of claim 2 , wherein the detectable lectin is Erythrina cristagalli lectin.
4. The method of claim 1 , wherein the pre-cancer is an adenoma.
5. The method of claim 1 , wherein the cancer is a carcinoma.
6. The method of claim 1 , further comprising surgical removal of the cancer or precancer.
7. The method of claim 6 , comprising the surgical removal of an adenoma.
8. The method of claim 1 , said subject having been determined to have a colorectal cancer or pre-cancer by a method further comprising obtaining the level of carcinoembryonic antigen (CEA) in a serum sample from the subject prior to step (d).
9. The method of claim 1 , said subject having been determined to have a colorectal cancer or pre-cancer by a method further comprising obtaining the level of galectin-3 ligand in a serum sample from the subject prior to step (d).
10. The method of claim 9 , said subject having been determined to have a colorectal cancer or pre-cancer by a method further comprising obtaining the level of carcinoembryonic antigen (CEA) and galectin-3 ligand in a serum sample from the subject prior to step (d).
11. The method of claim 1 , wherein step (a) comprises diluting the serum between 25-fold and 50-fold.
12. The method of claim 1 , wherein the quantitative immune-detection assay is an enzyme linked immunosorbent assay (ELISA), radioimmunoassay (RIA), immunoradiometric assay, fluoroimmunoassay, chemiluminescent assay or bioluminescent assay.
13. The method of claim 12 , wherein the quantitative immune-detection assay is an ELISA.
14. The method of claim 13 , wherein the quantitative immune-detection assay is a sandwich ELISA.
15. The method of claim 1 , wherein desialylating the serum comprises treating the serum with a mild acid.
16. The method of claim 1 , wherein desialylating the serum comprises treating the serum with a neuraminidase.
17. The method of claim 1 , wherein the antibody that binds haptoglobin is a polyclonal antibody.
18. The method of claim 1 , wherein the antibody that binds haptoglobin is bound to a substrate or a magnetic bead.
19. The method of claim 1 , wherein the antibody that binds haptoglobin is a polyclonal antibody raised against purified human haptoglobin.
20. The method of claim 1 , further comprising contacting the complex with a wash solution prior to step (c).