The loss of a specific chromosomal region provides a clue to the elucidation of the putative tumor suppressor gene implicated in the pathogenesis and progression of tumors. To delineate the specific region(s) involved in lymphomagenesis, we performed a survey of loss of heterozygosity for 11 polymorphic microsatellite loci scattered on variable chromosome arms. We examined 20 primary lymphoma samples, including both indolent and aggressive B-cell non-Hodgkin's lymphoma (B-NHL) and Hodgkin's disease (HD), and found a significant number of B-NHLs with loss of genetic material on chromosome arm 13q at the RB1 locus (50%; 4 of 8 informative cases for the RB1 locus). To specify the 13q deletion and to narrow the critical deleted region, we examined the same 20 lymphomas by intensive microsatellite mapping analysis using 12 microsatellite markers, mapping from 13q12.3 to 13q14. We confirmed the frequent 13q14 deletion to be in the vicinity of the RB1 locus (50% of the informative NHLs for at least 1 of 12 microsatellite loci; 5 of 10 aggressive NHLs and 2 of 4 indolent NHLs, but none of 6 HDs) and determined a subchromosomal region deleted in lymphoma on 13q14 defined by D13S164-D13S273, which is an overlapped region frequently lost in chronic lymphocytic leukemia. Taken together, our data indicate that the 13q alterations are present in a wide variety of NHLs including both indolent and aggressive B-NHLs, suggesting that loss of genetic material at chromosome band 13q14 may play an important role in the formation or development of a wide variety of mature lymphoid malignancies.