Mutations within the 5' region of FAS/CD95 gene in nodal diffuse large B-cell lymphoma

CD95 is a cell-surface receptor that mediates apoptosis. A possible association between CD95 mutations and extranodal diffuse large B-cell lymphomas (DLBCL) has been reported. To further elucidate this question, a mutation analysis within the 5' region and exon 9 of CD95 was performed in a series of 66 DLBCL patients, by polymerase chain reaction, single-strand conformational polymorphism, and sequencing in all cases. Four mutations, all within the 5' region, were detected in three cases of primary nodal DLBCL (6.3% of primary DLBCL), probably originated as by-products of the somatic hypermutation process. No CD95 mutations in the two analyzed regions were detected in primary extranodal DLBCL, mediastinal large B-cell lymphoma (MLBCL), and DLBCL arising from indolent low-grade lymphomas. Because of our results, a review of published data with respect to the site of mutations was performed, which suggested a different distribution of mutations in nodal and extranodal DLBCL.