DELETION OF GENETIC MATERIAL FROM A POLY(ADP-RIBOSE) POLYMERASE-LIKE GENE ON CHROMOSOME-13 OCCURS FREQUENTLY IN PATIENTS WITH MONOCLONAL GAMMOPATHIES

Recently, by using a probe far the nuclear DNA repair enzyme poly(ADP- ribose) polymerase gene, a pseudogene was found on the long arm of chr omosome 13, RFLP analysis demonstrates the presence of a common ''A'' allele and a rare (''B'' allele, which has a deletion of approximately 200 bp, This deletion occurs more frequently in blacks than in whites in the United States, In two B-cell malignancies, Burkitt's and folli cular lymphomas, there is a marked increased frequency of the expressi on of the B allele. Thus, we have analyzed the frequency of this allel e in another B-cell malignancy, multiple myeloma (MM), which is also m ore frequently observed in blacks, We studied 97 patients with MM (41 black and 56 white patients) and 30 patients with the related disorder monoclonal gammopathy of undetermined significance (MGUS; 13 black an d 17 white patients), The results demonstrate that the overall frequen cy of B allele expression (37%) is higher than in a noncancer control population (23%; P < 0.01), This difference is mainly due to the much higher frequency of B expression in black patients (62 versus 35% in b lack controls; P < 0.01), whereas there is no significant difference i n white patients (18 versus 14% in white controls), Overall, B allelic frequency is similar in patients with MM and MGUS. Matched germline a nd tumor DNA show identical patterns of expression of these alleles, T hese results suggest germline B allelic expression predisposes one to MM and MGUS.