Objective: To detect alterations of microsatellite loci [transforming growth factor beta receptor II (TGF-betaRII)(A)(10), TGF-betaRII(GT)(3), hMSH3(A)(8), hMSH6(C)(8), Bax(G)(8), IGFIIR(G)(8), IGFIIR(CT)(3)] and point mutations of TGF-betaRII (TGF-betaRII 452/454, TGF-betaRII 533).
Methods: PCR-SSLP, microdissection-PCR-SSLP, PCR-SSCP, clone sequencing and immunohistochemistry were used.
Results: The mutation rate of TGF-betaRII(A)(10) in RER+ (replication error positive) colorectal carcinomas was 33% (3/9). Similar mutations were also observed in adenomas with severe dysplasia. No mutations at other microsatellite loci were found. RER+ colorectal cancers mainly occurred in male patients at a young age and were more common in the colon than in the rectum (P < 0.05).
Conclusions: RER+ colorectal cancers were found in young males and commonly located in the colon. A one third mutation rate in TGF-betaRII(A)(10) in these patients is lower than that observed in western populations, which may imply diverse pathways of carcinogenesis of RER+ colorectal carcinoma. TGF-betaRII(A)(10) mutation may play a role in the transforming process from an adenoma with severe dysplasia to a full blown carcinoma.