Genetic alterations related to endoscopic treatment of colorectal tumors.

BACKGROUND AND AIM

Genetic indicators of endoscopic resection for colorectal carcinoma remain inconclusive. This study analyzed genetic changes in early colorectal tumors that could inform decisions for endoscopic procedures.

METHODS

A total of 83 colorectal tumors from 81 patients, including adenoma ( = 7), Tis-T1a ( = 22), T1b ( = 14), and advanced carcinoma ( = 40), were analyzed. Tis tumors ( = 16) and some T1 carcinomas ( = 11) were analyzed as mixed adenomas and carcinomas. Lesions were laser-capture microdissected for DNA extraction, and targeted sequencing of 50 cancer-related genes was performed. Genetic data were then correlated with clinical records, including magnifying endoscopic findings.

RESULTS

Numbers of gene alteration rates in and increased with tumor progression from adenoma to carcinoma. Frequencies of mutant variants in ( = 0.004) and rates of copy number loss in ( = 0.006) increased in carcinoma components of mixed tumors compared to adenoma components. Moreover, adenoma components of T1b carcinomas had higher mutation rates than Tis or T1a carcinomas ( = 0.011) and pure adenomas ( = 0.026). Gene alterations in ( = 0.0055) and ( = 0.0055) increased in cases with irregular surface patterns of magnifying endoscopic findings.

CONCLUSIONS

Numbers of copy number variations and and alterations were related to colorectal tumor progression. alteration rates in adenoma components were high in T1b carcinomas, warranting complete treatment with en bloc resection. Magnifying endoscopic findings might reflect the genetic status of colorectal tumors.