t(14; 18) translocations. (A) Restriction map of the 3′ region of the BCL2 gene showing position of breakpoints cloned in this study. Note the clustering of breakpoints in the region of the pMW-1 probe and the variant breakpoint in Karpas 231. *Leukemia 380, breakpoint not characterized in this study but cloned previously.39 (B) Sequence of pMW region and breakpoint sequences in case no. 1, SU-DUL5, and 380. JH sequences are underlined and n regions are in lowercase. JH segment involved in translocation is shown. B, BamHI; E, EcoRI; H, HindIII.