Presence of a carcinoma-associated antigen(s) in the spent chemically defined medium of a human colon carcinoma cell line.

The human colon carcinoma cell line HT-29 was adapted to grow in chemically defined medium (CDM). The spent CDM (S-CDM) was concentrated by Amicon filtration and the crude HT-29 S-CDM purified by 40% saturated (NH4)2 SO4 precipitation. The purified antigen was tested by a microcomplement fixation (MCF) assay against the sera of cancer patients of various histologic types and against the sera of normal donors. Fifteen of 20 (75%) colon cancer, 16/20 (80%) breast cancer sera, 14/19 (74%) lung cancer sera, and 13/20 (65%) miscellaneous carcinoma sera were positive in the MCF. By contrast, 2/21 (10%) melanoma sera, 7/20 (35%) sarcoma sera, and 2/19 (11%) normal sera were positive. These data suggest the presence of a carcinoma-associated antigen in the spent CDM of the HT-29 colon carcinoma cell line adapted to grow in CDM.