A 14q+ chromosome in a B‐cell acute lymphocytic leukemia and in a leukemic non‐endemic Burkitt lymphoma

Chromosome analysis using banding staining techniques was carried out on cells from a B‐cell acute lymphocytic leukemia (ALL) of the Burkitt type and a case of non‐endemic Burkitt lymphoma presenting as ALL. In both patients a marker chomo‐some 14q+ was found which was morphologically identical to those reported for endemic and non‐endemic Burkitt lymphoma and a few other B‐cell malignancies. However, the origin of the translocated segment could not be identified in either case. In addition, both patients had a 13q+ chromosome with a breakpoint in the 13q3 region but involving different material of unknown origin. Other marker chromosomes in the B‐cell ALL included rearrangements of chromosome arms 1q and 6q. Serial studies showed that cells with a partial duplication of the long arm of chromosome No. 1, in addition to the 14q+ chromosome, were important in the karyotype evolution of the malignant cell population. In this patient the 14q + chromosome had a brightly fluorescing satellite region indicating the probable monoclonal development of the leukemic cell population. From this and other reports it appears that the B‐cell type of ALL is characterized by a 14q+ chromosome. Because of the pathological and cytogenetic similarities between certain types of B‐cell ALL and Burkitt lymphoma it is suggested that they may be different manifestations of the same disorder.