Analyses of microsatellite instability and the transforming growth factor-beta receptor type II gene mutation in sporadic breast cancer and their correlation with clinicopathological features

To determine the incidence of microsatellite instability (MSI) and its rela tionship with both clinicopathologic parameters and patient survival, 101 c ases of breast cancer were investigated. In addition, transforming growth f actor-beta (TGF-beta) receptor type II (RII) gene mutation was also examine d to clarify the relation to MSI in breast cancer development. MSI and RII gene mutation were screened by single strand conformation polymorphism (SSC P). The mutations of the RII gene were confirmed by a direct sequence. An a ssociation between the MSI status and the clinicopathological features was examined to assess the potential of the MSI status as a prognostic indicato r in sporadic breast cancer cases. MSI was detected in 12 of 101 (11.9%) br east cancer cases. The positive MSI breast cancer cases showed relatively m ore advanced disease than negative MSI cases, and also exhibited relatively poorer prognoses. No RII gene mutations were observed in any of the breast cancer cases. Our data suggest that the MSI status may thus be a useful in dicator for the prognosis of sporadic breast cancer cases. However, the bre ast seems to be an infrequent target organ for cancer development through R II gene mutations. As a result, tumor progression through this pathway appe ars to be related to organ specificity. For positive MSI breast cancers, ot her target genes therefore still need to be identified.