Molecular epidemiology of follicular lymphoma in Chinese: relationship with bcl-2/IgH translocation and bcl-6 397G/C polymorphism.

The relative incidence of follicular lymphoma (FL) compared with diffuse large B-cell lymphoma (DLCL) is low in Chinese. This may be due to a lower incidence of t(14;18)-mediated disease, a rapid transformation of FL to DLCL, or a lower incidence of FL-prone genetic polymorphisms (e.g., bcl-6 G397C). Using a conventional and long-distance polymerase chain reaction technique, we showed that 93% (43/46) of Chinese FL cases are t(14;18) related and are molecularly indistinguishable from Caucasian cases. The translocation was uncommonly found in Chinese DLCL cases (8/58, 14%). Furthermore, the incidence of bcl-6 hypermutation in FL and DLCL cases appeared to be comparable. These data do not suggest a high incidence of transformation from FL to DLCL in Chinese. Sequencing study also did not show an increased incidence of G397C polymorphism (heterozygote+homozygotes) in FL compared to a population with Chinese background or DLCL cases (25+5% vs 30+4% vs 22+3%). The reasons for the lower incidence of FL in Chinese remain unanswered.