LOCALIZATION OF 2 TYROSINE KINASE RECEPTOR GENES WITH RESPECT TO THE 5Q35 CHROMOSOMAL BREAKPOINT OF KI-1 LYMPHOMA CELL-LINES

The consistency of the breakpoint on chromosome 5 at band 5q35 occurri ng in Ki-1 non-Hodgkin's lymphomas is highly suggestive of the involve ment of a locally altered gene in this disease. In this study, we anal yzed the potential involvement, in the translocation, of two receptor tyrosine kinase genes and putative oncogenes, FLT4 and FGFR4, previous ly localized near this breakpoint. Fluorescence in situ chromosomal hy bridization allowed us to refine their localization to sub-band 5q35.3 and to show that both genes are translocated to the derivative chromo somes in Ki-1 cell lines containing either a t(2;5) or a t(3;5). Pulse d-field gel electrophoresis showed that the FLT4 and FGFR4 genes are n ot physically linked, nor are they altered by the translocation. Final ly, Northern blot analysis showed that neither FLT4 nor FGFR4 is expre ssed in the Ki-1 cell lines, suggesting that they are not implicated i n the genesis of Ki-1 lymphomas. (C) 1993 Wiley-Liss, Inc.