Evidence for a new tumour suppressor locus (DBM) in human B–cell neoplasia telomeric to the retinoblastoma gene

Abstract

Roughly 25% of human B–cell chronic lymphocytic leukaemias (CLL) are characterized by a chromosomal lesion involving 13q14. This region contains the retinoblastoma gene (RB1). We have used a variety of techniques to determine whether RB1 or some other locus is the critical region in 11 cases of low grade B–cell malignancy (mainly CLL), all with deletions or translocations involving 13q14. In all cases, except the one with minimal disease, there was deletion or a structural lesion in the region of D13S25, with at least 4 cases showing homozyogous disruption. We conclude that D13S25 lies close to a tumour suppressor locus whose inactivation contributes to the initiation or progression of low grade B–cell malignancy. This locus is located at least 530 kilobases telomeric to RB1. © 1993 Nature Publishing Group.