Infrequent bax gene mutations in B-cell lymphomas

Mutation of the bar gene has been reported previously in lymphoid cell line s. In vitro experiments have shown that alterations in promoter and coding sequences of the gene abolish its apoptosis initiation function, which is c onsidered crucial for tumour development. To assess bax gene mutations in l ymphomagenesis, polymerase chain reaction-based single strand conformation polymorphism analysis (PCR-SSCP) and direct sequencing were used to detect altered sequences in the promoter region and all the sis exons and their fl anking sequences of the gene. Nodal and extranodal B-cell lymphomas (n = 11 2) including follicular lymphoma, mantle cell lymphoma, diffuse large B-cel l lymphoma, splenic marginal zone B-cell lymphoma and low- and high-grade m ucosa-associated lymphoid tissue (MALT) lymphomas were studied. Sequence al terations were found in 11 cases, Nine also shelved the same altered sequen ces in corresponding non-tumour control tissue samples, indicating polymorp hism. In the remaining two casts, sequence alterations (in exons 3 and 6) w hich altered the bas open reading frame were observed only in tumour tissue s, indicating tumour-specific point mutation, These results suggest that in hibition of apoptosis through bar gene mutations is unlikely to be a common event in B-cell lymphoma, at least in the major types of nodal and extrano dal B-cell lymphomas. (C) 1998 John Wiley & Sons, Ltd.