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 has been offered as a candidate tumor suppressor gene. We examined the frequency of hemizygous and homozygous deletions of p16/CDKN2 in head and neck squamous cell carcinoma (HNSCC) using a quantitative polymerase chain reaction (PCR) method.


METHODS
Twenty-one HNSCC and 12 corresponding normal DNA samples were examined for deletion of p16/ CDKN2 using PCR amplification and fluorescent quantification of DNA. All tumor and normal DNA samples were also amplified with fluorescein-labeled primers for a control DNA marker on chromosome 8p (D8S265). The ratios of the observed fluorescence of the p16/CDKN2 and 8p PCR products were compared.


METHODS
Patients with HNSCC scheduled to undergo surgical resection of their tumors were recruited. After the specimen was removed, a portion of the tissue was snap frozen for further DNA extraction.


RESULTS
Eight tumors (38%) had p16/CDKN2-D8S265 ratios of greater than 0.75; 8 tumors (38%), from 0.25 to 0.75; and 5 tumors (24%), of less than 0.25, the average ratio in this last group being 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.
Rawnsley
J D
JD
Department of Surgery, University of California-Los Angeles School of Medicine, USA.
Srivatsan
E S
ES
Chakrabarti
R
R
Billings
K R
KR
Wang
M B
MB
D002294:Carcinoma, Squamous Cell / Q000235:genetics*; D002352:Carrier Proteins / Q000235:genetics*; D002898:Chromosomes, Human, Pair 8; D002899:Chromosomes, Human, Pair 9; D019941:Cyclin-Dependent Kinase Inhibitor p16; D017931:DNA Primers; D004273:DNA, Neoplasm / Q000032:analysis; D005456:Fluorescent Dyes; D017353:Gene Deletion; D016147:Genes, Tumor Suppressor / Q000235:genetics*; D006258:Head and Neck Neoplasms / Q000235:genetics*; D006801:Humans; D016133:Polymerase Chain Reaction
D002352:Carrier Proteins; D019941:Cyclin-Dependent Kinase Inhibitor p16; D017931:DNA Primers; D004273:DNA, Neoplasm; D005456:Fluorescent Dyes