CLINICOPATHOLOGICALFEATURESOFRER+COLORECTALCARCINOMA

Objective: Replication errors (RER) is related toinitiation and development of colorectal carcinoma (CRC).To investigate the different biological behavior of RER+ andRER- CRC. Methods: Silver staining PCR-single strandconformation polymorphism (PCR-SSCP) and denaturedpolyacrylamide gel electrophoresis methods were used todetect microsatellite instability (MSI) at 4 loci onchromosome 2, 5, 17 in paraffin-embedded specimens of 60colorectal carcinoma (CRC) and their paired normal tissue.RER+ was scored if 2 or more loci behaved as gaining extrabands. Results: The results showed that RER+ was foundin 19/60 CRC, among which 7 cases had a family history.According to the criteria of Amsterdam, 4 were diagnosedas hereditary nonpolyposis colorectal cancer (HNPCC), andof which 3 cases were RER+. The ratio RER+ in HNPCC(75%) was significantly higher than that among sporadicCRC (28.5%). Most of the RER+ CRC have the feature ofpoorly differentiated adenocarcinoma (P<0.01), thetendency to involve the right side of the colon (P<0.05), ahigher proportion with a family history (P<0.05), Duckes' Aand B stage (P<0.05). Conclusion: The results indicatedthat RER+ is a relativcly common molecular cvent in CRC.There are different clinico-pathological features andbehavior between RER+ and RER- CPC.