Although genetic alterations of chromosome band 9p21 ± 22 occur frequently in head and neck squamous cell carcinoma (HNSCC) cell lines, alterations of the cyclindependent kinase inhibitor p16 INK4a located in this region are less common in corresponding primary tumors. To further investigate genetic alterations at 9p21 ± 22 and p16 INK4a in primary HNSCC, a paired set of 21 tumors and blood specimens that were shown previously to exhibit allelic loss at 3p and elsewhere, were tested for LOH at 9p21 ± 22 using eight di erent highly polymorphic marker. Sixteen of the samples (81%) exhibited LOH for at least one marker. Frequent LOH was found surrounding p16 INK4a and at three additional noncontiguous regions of 9p21 ± 22. No homozygous deletions were identi®ed. SSCP screening and direct sequence analysis led to the identi®cation of mutations the p16 INK4a gene in two tumors. p16 INK4a was not hypermethylated in any of the samples studied. Furthermore, there was no correlation between LOH at 9p21 ± 22 and the RB1 tumor suppressor gene. These ®ndings indicate that in the set of tumors that we tested, LOH at 9p21 ± 22 is common in primary HNSCC but that genetic alterations of p16 INK4a located in this region are unusual. Additional tumor suppressor genes at 9p21 ± 22 may therefore be involved in the pathogenesis of this tumor.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.