Genotypic analysis of tumor suppressor genes PTEN/MMAC1and p53in head and neck squamous cell carcinomas

Objectives:Tumor suppressor gene mutations in both p53and PTEN/MMAC1genomic DNA have been detected in many types of cancer. The purpose of this study was to investigate the presence and importance of PTEN/MMAC1mutations in squamous cell carcinomas. Methods:Exons of each gene were amplified after polymerase chain reaction (PCR) using genomic DNA derived from cell lines of squamous cell carcinoma of the head and neck (SCCHN) and snap‐frozen biopsy specimens from primary established head and neck tumors. The amplified and purified DNA was then sequenced directly. Result:As anticipated, point mutations of the p53gene were found in 80% of cell lines examined. A single base mutation in codon 151 was found in six of 10 cell lines studied. PTEN/MMAC1gene mutations were found in neither the cell lines tested nor the tumor biopsy samples. Conclusion:This study, as well as a large volume of data, confirms that mutations of the p53gene are frequent events in head and neck cancer cell lines. Although PTEN/MMAC1gene mutations have been found in a variety of carcinomas, this gene was not found to be mutated in SCCHN cell lines or in primary squamous cell carcinomas of the head and neck. This information is useful for further studies of mutations in these cell lines. Laryngoscope, 108:1553–1556, 1998