Exclusion of Leu1 and Leu2 genes as tumor suppressor genes in 13q14.3-deleted B-CLL

The chromosomal region 13q14.3 is frequently deleted in B cell chronic lymp hocytic leukemia (B-CLL) and it is supposed that a tumor suppressor gene, i nvolved in this leukemogenesis, is located in this area. The first exons of two genes, Leu1 and Leu2, mapped in a minimally deleted 13q14.3 region, ar e systematically lost in B-CLL sharing a 13q14.3 deletion. These two genes have been proposed as strong tumor suppressor gene candidates. However, in a study on 15 13q14.3 deleted B-CLL, we found three patients in which this critical region was not involved. Because of these results and that no muta tions were detected on the two genes in a previous study, we think that Leu 1 and Leu2 can be excluded as tumor suppressor genes.