No mutations of the Bub1 gene in human gastric carcinomas

Chromosomal instability in colorectal cancers is associated with functional loss of a mitotic check point partly due to mutations of the Bub1, one of the mitotic check point genes. However, mutation of coding sequences of hum an Bub1 gene has not been fully elucidated in gastric caicinomas. We perfor med sequencing analysis on reverse transcriptase-polymerase chain reaction (RT-PCR) product of the Bub1 cDNA (entire coding sequence) from 5 human gas tric carcinomas as well as On genomic PCR products of Bub1 kinase domain fr om 7 gastric carcinoma tissues. Although sequencing analysis of the Bub1 cD NA revealed several point mutations in 2 gastric carcinoma cases, we could not confirm the mutations by analyzing genomic DNA. Furthermore. genomic DN A sequencing revealed no mutations in the kinase domain of the Bub1 gene in any gastric carcinoma examined. These results suggest that mutational inac tivation of the Bub1 gene might not play a key role in human stomach carcin ogenesis.