R034: Comparative Genomic Hybridization of Primary Sinonasal Adenocarcinomas

Abstract

Decreased expression and growth suppression of tazarotene-induced gene 1 (TIG1) were reported in prostate cancer. In this study, we examined the possibility of TIG1 transcriptional silencing by hypermethylation in head and neck cancer and other tumors.Methods: We extracted DNA and total RNA from six head and neck (O11, O12, O13, O19, O22, and O28), four prostate (PC3, LNCap, LNCap-FCG, and DU145), six lung (H647, H1975, A549, H1299, H1703, and H23), and three bladder cancer cell lines (J82, HT1376, and HTB4). We checked the methylation status of TIG1 by methylation-specific PCR (MSP) and RT-PCR. We also examined primary cancer tissues (32 head and neck cancer, 31 prostate cancer, and 30 lung cancer) and normal samples.Results: We found that all of six head and neck (100%), three of four prostate (75%), and two of six lung (33%) cancer cell lines were methylated. RT-PCR analysis confirmed absence of TIG1 expression in nine cell lines with methylation. We checked primary cancer by. MSP and found TIG1 methylation in 16 of 32 head and neck cancers, 17 of 31 prostate cancers, and 13 of 30 lung cancers. Normal head and neck and prostate tissues were free of methylation.Conclusion: Our results support the notion that methylation is an important mechanism of TIG1 inactivation and a target event in major human tumors.Significance: TIG1 methylation represented a new molecular marker for targeted diagnostic and therapeutic approaches in head and neck cancer.Support: None reported.