What types of colorectal cancer overexpress the MAGE protein?

Background/aims: Tumor-specific antigens such as Melanoma-associated antigens could be attractive targets for immunotherapy. It will be a great help for cancer immunotherapy to distinguish what types of tumor expresses tumor-specific antigen.
Methodology: We investigated the expression pattern of MAGE-A1 by immunohistochemical typing methods in human colorectal cancers obtained from consecutive patients undergoing surgical treatment at the hospital of the University of Tokyo.
Results: In 35 of 89 cases (39%), MAGE-A1 positive immunoreactivity was detected in the malignant glands. MAGE-A1 positive immunoreactivity was significantly higher among the patients under the age of 70 than among those 70 years of age and older (p=0.04). Among the patients under the age of 70, the tumors located in the distal colon (descending colon, sigmoid colon and rectum) showed significantly more positive MAGE-A1 immunoreactivity than those in the proximal colon (cecum, ascending colon and transverse colon) (p=0.04). The expression pattern of MAGE-A1 was not associated with gender, size, depth, histological type, vessel invasion, lymphatic invasion, lymph nodal invasion or stage of disease.
Conclusions: Relatively better results can be expected with MAGE-A1 immunotherapy among patients with distal colon cancer under the age of 70.