Bax mutations are an infrequent event in indolent lymphomas and in mantle cell lymphoma.

BACKGROUND AND OBJECTIVES The Bax gene is one of the most important genes involved in apoptosis regulation. Recently, it has been proposed that inactivating mutations of this death agonist may contribute to the pathogenesis of human tumors. This study was aimed at defining the status of the Bax gene in indolent lymphomas. DESIGN AND METHODS Fifty paraffin-embedded biopsies from indolent lymphomas (10 small lymphocytic lymphomas, 5 immunocytomas, 20 follicular lymphomas and 15 marginal zone lymphomas) and 10 mantle cell lymphomas ( MCL ) were studied. All six exons of the Bax gene, together with their flanking sequences, underwent mutational analysis by PCR-SSCP followed by direct sequencing of positive cases. Moreover, Bax protein expression was investigated in all samples by immunohistochemical analysis. RESULTS All analyzed cases showed wild type Bax gene alleles and variable levels of Bax protein expression. INTERPRETATION AND CONCLUSIONS This study indicates that deregulation of apoptotic control in indolent lymphomas and MCL is not caused by Bax mutations and that other molecular mechanisms must, therefore, be involved.