bcl‐2 Gene Rearrangement Analysis of Japanese Follicular Lymphomas by Polymerase Chain Reaction in Formalin‐fixed, Paraffin‐embedded Tissue Specimens

The prevalence of chromosomal translocation t(14;18) was examined in 41 cases of follicular lymphoma covering all histopathological subtypes, using the polymerase chain reaction and hybridization method with non‐radioactive oligonucleotide probes. DNAs were extracted from unfixed fresh‐frozen and/or formalin‐fixed paraffin‐embedded biopsy specimens. The t(14;18) chromosomal translocation, resulting in bcl‐2‐J(H) (immunoglobulin heavy chain gene joining segment) fusion gene, was detected in 7 (36.8%) of 19 follicular small cleaved cell lymphomas and 6 (54.5%) of 11 follicular mixed, small cleaved cell and large cell lymphomas. Meanwhile, 11 cases of follicular large cell lymphoma revealed no bcl‐2‐J(H) fusion gene. There was a statistically significant difference in the frequency of bcl‐2‐J(H) rearrangement between follicular, small cleaved cell and large cell lymphoma (two‐sided Fisher exact test, P= 0.049). The difference of bcl‐2 rearrangement frequency between follicular, mixed and large cell lymphoma was also statistically significant (P= 0.012).