Novel germline CDK4 mutations in patients with head and neck cancer

BACKGROUND: Cyclin-dependent kinase 4 (CDK4) together with its regulatory subunit cyclin D1, governs cell cycle progression through G(1) phase. Cyclin-dependent kinase inhibitors, including p16(INK4A) in turn regulate CDK4. In particular, deregulation of the p16/CDK4/cyclin D1 complex has been established in a variety of human tumors including gliomas, sarcomas, melanoma, breast and colorectal cancer. However, changes in CDK4 have rarely been observed. METHOD: In this study we used a combination of PCR-SSCP and direct sequencing for mutational screening of CDK4. DNA was isolated from peripheral blood leukocyte of patients with squamous cell carcinoma of head and neck, for screening germline mutations in coding regions of CDK4. RESULTS: Variations observed in exon 2 and 5 were three missense mutations, g5051G > C (Ser52Thr), g5095G > C (Glu67Gln), g5906C > A, g5907C > G (Pro194Ser) and novel frame shift mutations g7321_23delTGA, g7121_7122insG, g7143delG in exon 7 and 3′UTR respectively. CONCLUSION: In conclusion, two novel mutations were found in N terminal domain which indicates that CDK4 mutation may play a major role in the development and progression of squamous cell carcinoma of head and neck.