Correlated expression of mRNAs of carcinoembryonic antigen and nonspecific cross-reacting antigen genes in malignant and nonmalignant tissues of the colon.

Expression of carcinoembryonic antigen (CEA) and nonspecific cross-reacting antigen (NCA) mRNAs were observed in malignant and nonmalignant colon tissues by Northern blot analysis. CEA mRNA was detected together with NCA mRNA in nine cultured cell lines, with the exception of the lung carcinoma A549 cell line, and in 19 colon tissue specimens, including carcinomas, adjacent noninvaded tissues and adenomas. When we compared the intensity of the hybridization signal for CEA or NCA mRNA among adenomas, carcinomas and adjacent noninvaded tissues, NCA mRNA rather than CEA mRNA was highly expressed in carcinomas compared to adjacent nonivaded tissues. When, however, the relation between the intensities of hybridization signals for CEA and NCA mRNAs were evaluated in five colon carcinoma cell lines and 19 colon tissue specimens, a statistically significant correlation was observed (gamma = 0.462, P less than 0.01). These data suggest that NCA may be more useful as a tumor marker for colon carcinoma than CEA at the level of mRNA, and that transcriptions of the CEA and NCA genes might be regulated by some common mechanisms in malignant and nonmalignant tissues of the colon.