B-CELL NON-HODGKINS-LYMPHOMA CELL-LINE (KARPAS-1106) WITH COMPLEX TRANSLOCATION INVOLVING 18Q21.3 BUT LACKING BCL2 REARRANGEMENT AND EXPRESSION

A B-cell non-Hodgkin's lymphoma (B-NHL) cell line (Karpas 1106) with a n unusual three-way translocation involving 18q21.3 has been derived f rom a patient with mediastinal lymphoblastic B-NHL. Although conventio nal cytogenetics showed a derivative 18q(-) identical to that seen in cases with t(14;18)(q32.3;q21.3), no translocations of either chromoso me 14 could be detected. Instead fluorescent in situ hybridization ana lysis using a chromosome-18 paint showed that the segment 18q21.3-18qt er had become sandwiched on a derivative chromosome X between segments Xqter-c-Xq28 and 13q12-qter, with the centromeric site of 18q21.3 sub band juxtaposed to the X sequences. Pulsed-field DNA blots failed to d etect rearrangement of the BCL2 gene. Conventional DNA blots using a v ariety of restriction digests and both 5' and 3' BCL2 and FVT 1 probes also failed to detect rearrangement in Karpas 1106. A rearranged frag ment seen only in HindIII digests with 5' BCL2 probes may represent a local microalteration, which is either a mutation or small deletion in volving the HindIII site as seen in other cases of B-NHL. Neither BCL2 RNA nor BCL2 protein expression were detected. These and other data s uggest that genes at 18q21.3, other than BCL2 and FVT1, may be targets for translocation in certain subgroups of B-NHL. (C) 1994 by The Amer ican Society of Hematology.