QUANTITATIVE-ANALYSIS OF CEA EXPRESSION IN COLORECTAL ADENOCARCINOMA AND SERUM - LACK OF CORRELATION

Tissues and sera from 110 patients diagnosed with colorectal primary c arcinoma, 20 patients with benign colorectal diseases and 31 healthy d onors were subjected to quantitative CEA analysis. Multiple samples fr om tumor lesions and autologous histologically normal mucosa (10 cm fr om the tumor) were obtained at the time of surgery (cancer patients) o r endoscopy (benign patients and healthy volunteers). CEA content was measured in protein extracts obtained from these tissues using a quant itative RIA method. A limit of normality for CEA content was establish ed as 300 ng/mg of protein. When this was taken as cut-off, 104 of 110 (94.5%) tumor lesions and 51 of 110 (46.4%) autologous histologically normal colonic mucosa from cancer patients had elevated CEA levels. N o correlation with stage of disease was found, while a correlation was observed with degree of tumor differentiation. A statistically signif icant difference between CEA content in tumor lesions and in histologi cally normal mucosa from cancer patients was observed (p = -0.001). Mo reover, CEA content was statistically higher in the normal mucosa from cancer patients than in that from healthy donors (p = 0.005). CEA con tent in tissue specimens from benign lesions differed significantly fr om that in tissue from healthy donors (p = 0.005) and in carcinoma les ions (p < 0.001). The highest CEA content was observed in benign lesio ns with severe dysplasia. No statistical correlation between CEA conte nt in carcinoma tissues and serum CEA levels (r = 0.195, p = .13) was found. Therefore, in considering diagnosis or therapy with anti-CEA MA bs for colorectal-carcinoma patients, or potential therapies with anti -CEA recombinant vaccines, serum CEA levels should not be taken as ind icating CEA expression in tumor lesions. (C) 1997 Wiley-Liss Inc.