ABSENCE OF P18 MUTATIONS OR DELETIONS IN LYMPHOID MALIGNANCIES

p18 is a recently described cyclin-dependent kinase inhibitor (CDK-l) with homology to p16 and p15. The latter two CDK-ls have been implicat ed as possible tumor suppressor genes in a wide variety of human tumor s, including hematological malignancies. Because of p18's structural a nd functional homology to p16 and p15, we hypothesized that it may als o function as a tumor suppressor gene in some lymphoid malignancies. T o explore this possibility we examined 81 primary lymphoid tumors for deletion and mutation of p18. The primary tumors included 40 T cell ma lignancies and 41 B cell malignancies. None of the lymphoid tumors stu died possessed deletions of p18, including a group of lymphoblastic ly mphomas which we previously reported to have deletions of p16 and p15. PCR-SSCP analysis of the p18 gene identified a single polymorphism of codon 114, but failed to demonstrate mutations in any of the lymphoid tumors. These results do not support a role for p18 in the pathogenes is of the lymphoid neoplasms studied.