Translocation breakpoint in t(11;14) in B-cell leukemia is not at the rare fragile site at 11q13.3.

The cloned breakpoint at 11q13.3 of the t(11;14)(q13.3;q32.3) in a B-cell lymphocytic leukemia (B-CLL) was used to analyze DNA from individuals with and without the rare folate-sensitive fragile site at 11q13.3. On Southern blots there were no discernible differences. Subclones of the ends of the leukemia breakpoint clone were prepared and used for in situ hybridization to chromosomes expressing fra(11)(q13.3). Both subclones hybridized distal to the fragile site. These experiments indicate that the breakpoints at 11q13.3 in B-CLL (and in a B-cell lymphoma) are not at the fragile site at 11q13.3.