EXPRESSION OF P21RAS-RELATED PROTEIN IN THE PLASMA AND TISSUE OF PATIENTS WITH ADENOMAS AND CARCINOMAS OF THE COLON

Over-expression of p21 ras-related protein was determined in the plasm a by immunoblotting and in the tissue by immuno-histochemistry in a co hort of patients undergoing colonoscopy, In the plasma samples, p21 ra s over-expression was detected in: 9% (4/47) of normal controls; 21% ( 13/61) of individuals with normal colonoscopies but with a prior histo ry of colonic neoplasia; 12% (4/33) of small adenoma patients; 29% (6/ 21) of large adenoma patients; 63% (5/8) of carcinoma-in-adenoma patie nts; 50% (2/4) of Dukes' A carcinoma patients; and 20% (2/10) of Dukes ' B-D carcinoma patients, In the tissue samples, p21 ras over-expressi on was detected in: 25% (2/8) of small adenoma patients; 44% (4/9) of large adenoma patients; 100% (4/4) of carcinoma-in-adenoma patients; a nd 33% (1/3) of Dukes' B-C carcinoma patients. For matched plasma-tiss ue pairs, there was a statistically significant correlation for p21 ra s over-expression (R = 0.47, p = 0.02).