Hypermethylation of the tumor suppressor gene Rassfia and frequent concomitant loss of heterozygosity at 3p21 in cervical cancers

Loss of heterozygosity (LOH) at chromosome 3p21 is frequent in cervical cancers. The candidate tumor suppressor gene, RASSFIA located at 3p21.3, is found to be inactivated in several major human cancers, implicating its significance in carcinogenesis. We aimed to investigate the status of RASSFIA in cervical cancers. The mutation and methylation status of RASSFIA were analysed in 4 cervical cancer cell lines, SO primary cervical cancers including 33 squamous cell carcinoma (SCC), 17 adenocarcinoma (AC) and 11 normal controls. The primary cancer samples were also detected for LOH at 3p21 and human papillomavirus (HPV). Hypermethylation of RASSFIA was detected in 30% of SCC, 12% of AC and in I of the 4 cancer cell lines but was absent in all normal cases. Methylation of the cancer cell line was associated with loss of gene expression, which was restored by demethylation. About 67% (8 of 12) of hypermethylated primary cancers showed concomitant LOH at 3p21. No somatic mutation was found in all primary cancer samples or cell lines but 2 cases showed germline polymorphism at codon 133. Oncogenic HPV DNAs were found in most cancer samples. No correlation was detected between RASSFIA-hypermethylation or LOH at 3p21 and age of patient, HPV genotype, tumor grade and stage. Hypermethylation of RASSFIA occurs in a subset of cervical cancers, among which concomitant LOH at 3p21 is common. The results supported that RASSFIA may be one of the cervical cancer-related tumor suppressor genes located at 3p21 regions. (C) 2003 Wiley-Liss, Inc.