N Xu1, H Qiu, Y Ding. 1. Department of Pathology, First Military Medical University, Guangzhou 510515.
Abstract
OBJECTIVE: To study the relationship between DNA replication error and development of colorectal carcinoma (CRC). METHODS: Silver staining PCR-SSCP and denatured polyacrylamide gel electrophoresis methods were used to detect microsatellites instability (MSI) at 4 loci on chromosome 2, 5, 17 in paraffin embedded specimens of 60 CRC and their paired normal tissue. If replication errors (RER) were found at 2 or more loci, then a diagnosis of RER+ was made. RESULTS: RER+ was observed in 19/60 CRC, among which 7 cases had CRC family history. According to Amsterdam criteria, 4 were diagnosed as HNPCC(hereditary nonpolyposis colorectal cancer), of which 3 cases were RER+. The ratio of RER+ in HNPCC (75%) was significantly higher than that among sporadic CRC (28.5%). Most RER+ CRC have features of poorly differentiated adenocarcinoma (P < 0.01), tendency for right side involvement of the colon (P < 0.05) and a higher proportion with family history (P < 0.05). Rate of Dukes A and B stage higher than C and D stage (P < 0.05). CONCLUSION: RER+ is a relatively common molecular event in CRC. RER+ CRC and RER- CRC have different clinicopathological features and behavior.
OBJECTIVE: To study the relationship between DNA replication error and development of colorectal carcinoma (CRC). METHODS:Silver staining PCR-SSCP and denatured polyacrylamide gel electrophoresis methods were used to detect microsatellites instability (MSI) at 4 loci on chromosome 2, 5, 17 in paraffin embedded specimens of 60 CRC and their paired normal tissue. If replication errors (RER) were found at 2 or more loci, then a diagnosis of RER+ was made. RESULTS:RER+ was observed in 19/60 CRC, among which 7 cases had CRC family history. According to Amsterdam criteria, 4 were diagnosed as HNPCC(hereditary nonpolyposis colorectal cancer), of which 3 cases were RER+. The ratio of RER+ in HNPCC (75%) was significantly higher than that among sporadic CRC (28.5%). Most RER+ CRC have features of poorly differentiated adenocarcinoma (P < 0.01), tendency for right side involvement of the colon (P < 0.05) and a higher proportion with family history (P < 0.05). Rate of Dukes A and B stage higher than C and D stage (P < 0.05). CONCLUSION:RER+ is a relatively common molecular event in CRC. RER+ CRC and RER- CRC have different clinicopathological features and behavior.