Methylation Analysis and mRNA Expression Status of ING1 Splicing Variants in Head and Neck Carcinomas

We previously reported the characterization of the genomic structure of the human ING1 gene and found tumor specific missense mutations. We also demonstrated that four mRNA variants were transcribed from three different promoter regions. In this study, we examined the mRNA expression of two major splicing variants of ING1 gene in 40 matched samples of normal and tumor tissues from head and neck cancers by RT-PCR. One of the splicing variant, p24, showed decreased and increased expression in 51% and 27% of the samples, respectively, while another major variant, p33, demonstrated low and high mRNA expression in 20% and 35% of the samples, as compared to normal controls. To elucidate the silencing mechanism of the ING1 gene, we examined the methylation status of each splicing variant. Our results suggest that alternative variants of ING1 gene may have different role in the carcinogenic pathway of head and neck cancers.