[Study of p16INK4/CDKN2 gene homozygous deletions and point mutation in squamous cell carcinoma of buccal mucosa].
OBJECTIVE
To explore the correlation between homozygous deletions and mutation of p16 gene and the carcinogenesis and progression of squamous cell carcinoma of buccal mucosa.


METHODS
Thirty buccal cancers, 10 leukoplakias and 8 buccal mucosas were involved. DNA was extracted from the tissues. PCR was used to analyses homozygous deletion of p16 gene. PCR-SSCP-DNA sequencing was performed to detect the point mutation of p16 gene. Immunohistochemical techniques were used to detect the expression of P16 protein.


RESULTS
Gene deletions and point mutations were not found in leukoplakia and normal buccal mucosa. Gene deletions were found in 7 samples out of 30 cases of squamous cell carcinoma of buccal mucosa (23.3%), while point mutations were found in 5 samples out of 30 cases of squamous cell carcinoma of buccal mucosa (16.7%). Sequencing analysis showed that 5 cases point mutations were missense mutations, occurred on exon 2. Three cases occurred in the same point, codon 99 (GAT --> AAT). The result of immunohistochemical stains showed that 11 out of 12 cases gene inactivation did not expressed P16 protein.


CONCLUSIONS
Homozygous deletion and point mutation of p16 were the main pattern of gene inactivation in squamous cell carcinoma of buccal mucosa. There was a closely correlation between p16 gene inactivation and the carcinogenesis of squamous cell carcinoma of buccal mucosa.
Dong
Yu-Ying
YY
Dept. of Oral and Maxillofacial Surgery, School of Stomatology, Hebei Medical University, Shijiazhuang 050017, China.
Wang
Jie
J
Dong
Fu-Sheng
FS
Wang
Xu
X
Zhang
Ying-Huai
YH
Guo
Li-Hua
LH
D002294:Carcinoma, Squamous Cell; D019941:Cyclin-Dependent Kinase Inhibitor p16; D017353:Gene Deletion; D019942:Genes, p16; D006801:Humans; D009061:Mouth Mucosa; D009154:Mutation; D017354:Point Mutation
D019941:Cyclin-Dependent Kinase Inhibitor p16