Selective deletion of p14(ARF) exon 1 beta of the INK4a locus in oral squamous cell carcinomas of Indians

The tumor suppressor gene - p16 INK4/CDKN2/MTS1 and its alternate splice pr oduct p14(ARF), constitute the INK4a locus. We have examined the integrity of exon 1 beta of p14(ARF) gene of oral squamous cell carcinomas (n=58) in untreated Indian patients, No mutations were detected in this region by PCR -SSCP analysis of the turner DNA's. Further, PCR-based analysis revealed ho mozygous deletions of exon 1 beta in 14 of the 58 tumors; these results wer e confirmed by hybridization of tumor DNAs with exon 1 beta specific probe. The deletions were limited to the exon 1 beta while the exons coding p16/I NK4 were not affected. Except in two cases these deletions were mutually ex clusive to the p53 inactivating mutations. These observations suggest an al ternate mechanism of loss of p14(ARF) in the genesis of oral squamous cell carcinomas. (C) 2001 Elsevier Science Ltd. All rights reserved.