Transforming growth factor β type II receptor expression in gastric cancer:: Evidence for two independent subgroups

Transforming growth factor beta type II receptor (TGFbeta-, IIR) has been found to be altered in primary gastrointestinal carcinomas. So far relatively few facts are known about the expression of TGFbeta - IIR in primary gastric cancer. Therefore, in the present study, TGFbeta - IIR expression was analyzed in 130 primary gastric carcinomas and correlated with clinicopathological findings, the presence of a mutator phenotype, the mutational status of the TGFbeta - IIR polyadenine tract and survival. TGFbeta - IIR expression was analyzed immunohistochemically. Microsatellite instability was evaluated using a PCR - based assay and the polyadenine run inside the TGFbeta IIR gene was sequenced. A complete loss of TGFbeta - IIR expression could be found in 55 (42.3%) of these carcinomas. Loss of TGFbeta - IIR expression was significantly correlated with diffuse - type carcinomas according to the Lauren classification as well as with signet ring cell carcinomas and a lower grade of differentiation. No correlation was found with the overall prognosis, the presence of a mutator phenotype, or a mutated TGFbeta - IIR. Thus, our data suggest the existence of a further definite subgroup of diffuse - type gastric carcinomas with altered TGFbeta - IIR expression, independent from a mutator phenotype with TGFbeta - IIR gene mutations. However, according to our results,,in gastric cancer neither loss of TGFbeta - IIR expression nor mutations of the TGFbeta - IIR are of prognostic value.