We investigated a series of 11 colorectal carcinomas by Northern blot and isotopic in situ hybridization (ISH), demonstrating underexpression of CD66a and CGM2 in the majority of the carcinomas as compared with the normal mucosa, whereas NCA was overexpressed.
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.
Hybridization was clearly detected throughout the cytoplasm of 7 out of 15 adenomas and 13 out of 15 carcinomas with the CEA cDNA probe, and in 6 out of 15 adenomas and 10 out of 15 carcinomas with the NCA cDNA probe.