High frequency of t(14;18) in Hodgkin's lymphoma associated with follicular lymphoma.

t(14;18) is a common cytogenetic abnormality in B-cell lymphoma, especially in follicular lymphoma (FL), but is rarely seen in Hodgkin's lymphoma (HL). However, due to the small number of cases, the incidence of t(14;18) in HL associated with FL remains unclear. In this study, we applied chromogenic in situ hybridization and fluorescence in situ hybridization for t(14;18) on paraffin-embedded tissue from four HL associated with FL cases and 11 HL cases without a history of FL for comparison. t(14;18) was present in all of the three successfully-tested HL associated with FL cases and one case without a history of FL. The frequency of t(14;18) was significantly high in HL associated with FL (p = 0.013). All Hodgkin's and Reed-Sternberg (HRS) cells having t(14;18) showed immunoreactivity for BCL2 and were negatively stained for nuclear factor-κB (NF-κB), even in Epstein-Barr virus (EBV)-infected cases. However, HRS cells without t(14;18) showed BCL2 and NF-κB immunoreactivity in 33% and 57% of cases, respectively. There was an inverse correlation between t(14;18) and NF-κB. In conclusion, we assume the incidence of t(14;18) in HL associated with FL is higher than previously believed and BCL2 expression derived from t(14;18) may play a role in the pathogenesis of HL associated with FL.