MAJOR AND MINOR BREAKPOINT SITES OF CHROMOSOMAL TRANSLOCATION T(1418)IN SUBTYPES OF NON-HODGKINS-LYMPHOMAS

The frequencies of major breakpoint region (MBR) and minor cluster reg ion (MCR) breakpoint sites of t(14;18) were examined by polymerase cha in reaction and Southern blotting in 50 non-Hodgkin's lymphomas with c ytogenetic evidence of t(14;18). A translocation breakpoint was detect ed in 41 cases (82%). The MBR was involved in 66%, and the MCR in 16% of the cases. Most cases in the present series were lymphomas with a f ollicular or diffuse growth pattern, 38 being of the centroblastic/cen trocytic type and eight of the centroblastic type. The series also inc luded four lymphomas of probable non-follicular center cell origin. MB R and/or MCR breakpoints were found in all studied lymphoma subtypes a nd in the majority of these most of the breakpoints were in the MBR an d a minor portion of the breakpoints in the MCR. Our results suggest t hat a breakpoint site is not related to growth pattern or neoplastic c ell type in follicular center cell lymphomas with t(14;18).