Expression and mutational analysis of Cip/Kip family in early glottic cancer

Background: Genetic alteration of cyclin-dependent kinase inhibitors has been associated with carcinogenesis mechanisms in various organs. Objective: This study aimed to evaluate the expression and mutational analysis of Cip/Kip family cyclin-dependent kinase inhibitors (p21 CIP1/WAF1 , p27 KIP1 and p57 KIP2 ) in early glottic cancer. Methods: Expressions of Cip/Kip family and p53 were determined by quantitative reverse transcription polymerase chain reaction and densitometry. For the analysis of p21 inactivation, sequence alteration was assessed using single-strand conformational polymorphism polymerase chain reaction. Additionally, the inactivation mechanism of p27 and p57 were investigated using DNA methylation analysis. Results: Reduced expression of p27 and p57 were detected in all samples, whereas the expression of p21 was incompletely down-regulated in 6 of 11 samples. Additionally, single-strand conformational polymorphism polymerase chain reaction analysis showed the p53 mutation at exon 6. Methylation of p27 and p57 was detected by DNA methylation assay. Conclusion: Our results suggest that the Cip/Kip family may have a role as a molecular mechanism of carcinogenesis in early glottic cancer.