High frequency of p16 (CDKN2/MTS-1/INK4A) inactivation in head and neck squamous cell carcinoma.
The tumor suppressor gene p16 (CDKN2/MTS-1/INK4A) can be inactivated by multiple genetic mechanisms. We analyzed 29 invasive primary head and neck squamous cell carcinomas (HNSCC) for p16 inactivation with immunohistochemistry utilizing a new monoclonal antibody (mAb), DCS-50. p16 staining of the primary lesions was correlated with genetic analysis including: (a) detailed microsatellite analysis of markers at the p16 locus to detect homozygous deletion; (b) sequence analysis of p16; and (c) Southern blot analysis to determine the methylation status of the 5' CpG island of p16. Twenty-four of 29 (83%) head and neck squamous cell carcinoma tumors displayed an absence of p16 nuclear staining using immunohistochemistry. Of these 24 tumors, we found that 16 (67%) harbored homozygous deletions, 5 (21%) were methylated, 1 displayed a rearrangement at the p16 locus, and 1 displayed a frameshift mutation in exon 1. These data suggest that: (a) inactivation of the p16 tumor suppressor gene is a frequent event in squamous cell carcinomas of the head and neck; (b) p16 is inactivated by several distinct and exclusive events including homozygous deletion, point mutation, and promoter methylation; and (c) immunohistochemical analysis for expression of the p16 gene product is an accurate and relatively simple method for evaluating p16 gene inactivation.
Reed
A L
AL
Department of Otolaryngology Head and Neck Surgery, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205-2196, USA.
Califano
J
J
Cairns
P
P
Westra
W H
WH
Jones
R M
RM
Koch
W
W
Ahrendt
S
S
Eby
Y
Y
Sewell
D
D
Nawroz
H
H
Bartek
J
J
Sidransky
D
D
D015139:Blotting, Southern; D002294:Carcinoma, Squamous Cell / Q000235:genetics*; D002352:Carrier Proteins / Q000032:analysis / Q000235:genetics*; D019941:Cyclin-Dependent Kinase Inhibitor p16; D004273:DNA, Neoplasm / Q000032:analysis; D005091:Exons; D016147:Genes, Tumor Suppressor; D006258:Head and Neck Neoplasms / Q000235:genetics*; D006801:Humans; D007150:Immunohistochemistry; D008745:Methylation; D009154:Mutation
D002352:Carrier Proteins; D019941:Cyclin-Dependent Kinase Inhibitor p16; D004273:DNA, Neoplasm