GENOTYPIC ANALYSIS OF TUMOR-SUPPRESSOR GENES PTEN MMAC1 AND P53 IN HEAD AND NECK SQUAMOUS-CELL CARCINOMAS/

Objectives: Tumor suppressor gene mutations in both p53 and PTEN/MMAC1 genomic DNA have been detected in many types of cancer. The purpose o f this study was to investigate the presence and importance of PTEN/MM AC1 mutations in squamous cell carcinomas. Methods: Exons of each gene were amplified after polymerase chain reaction (PCR) using genomic DN A derived from cell lines of squamous cell carcinoma of the head and n eck (SCCHN) and snap-frozen biopsy specimens from primary established head and neck tumors, The amplified and purified DNA was then sequence d directly. Result: As anticipated, point mutations of the p53 gene we re found in 80% of cell. lines examined, A single base mutation in cod on 151 was found in six of 10 cell lines studied, PTEN/MMAC1 gene muta tions were found in neither the cell lines tested nor the tumor biopsy samples. Conclusion: This study, as well as a large volume of data, c onfirms that mutations of the p53 gene are frequent events in head and neck cancer cell lines. Although PTEN/MMAC1 gene mutations have been found in a variety of carcinomas, this gene was not found to be mutate d in SCCHN cell lines or in primary squamous cell carcinomas of the he ad and neck. This information is useful for further studies of mutatio ns in these cell lines.