DELETION ANALYSIS OF THE P16 CDKN2 GENE IN HEAD AND NECK SQUAMOUS-CELL CARCINOMA USING QUANTITATIVE POLYMERASE CHAIN-REACTION METHOD/

Background: Recently, the p16/CDKN2/MTS1 gene in the 9p21-22 region ha s been offered as a candidate tumor suppressor gene. We examined the f requency of hemizygous and homozygous deletions of p16/CDKN2 in head a nd neck squamous cell carcinoma (HNSCC) using a quantitative polymeras e chain reaction (PCR) method. Design: Twenty-one HNSCC and 12 corresp onding normal DNA samples were examined for deletion of p16/CDKN2 usin g PCR amplification and fluorescent quantification of DNA. All tumor a nd normal DNA samples were also amplified with fluorescein-labeled pri mers for a control DNA marker on chromosome 8p (D8S265). The ratios of the observed fluorescence of the p16/CDKN2 and 8p PCR products were c ompared. Setting and Participants: Patients with HNSCC scheduled to un dergo surgical resection of their tumors were recruited. After the spe cimen was removed, a portion of the tissue was snap frozen for further DNA extraction. Results: Eight tumors (38%) had p16/CDKN2-D8S265 rati os of greater than 0.75; 8 tumors (38%), from 0.25 to 0.75; and 5 tumo rs (24%), of less than 0.25, the average ratio in this last group bein g 0.06. Conclusions: These ratios suggest a higher rate of homozygous deletion than previously reported and significant probable hemizygous deletion of the p16/CDKN2 gene in HNSCC.