Hypermethylation of the CpG island of the RASSF1A gene in ovarian and renal cell carcinomas

Homozygous deletion and loss of heterozygosity (LOH) at chromosome 3p21 hav e been observed in several types of human cancer including lung cancer and breast cancer. In previous work, we cloned and identified the human RAS ass ociation domain family IA gene (RASSFIA) from the lung tumor suppressor loc us 3p21.3. The CpG island and promoter region of RASSFIA is highly methylat ed in primary lung and breast tumors. In this study, we analyzed the methyl ation status of the promoter region of RASSFIA in 3 different tumor types: colon, ovarian and renal cell carcinoma. In colon cancers, 3 out of 26 tumo r tissues (12%) were methylated at the CpG island of the RASSFIA gene. Rena l and ovarian cancers showed a much higher frequency of methylation. For ov arian tumors, 8 out of 20 tumors (40%) were methylated. In renal cell carci nomas, 18 out of 32 cases (56%) were methylated. For all tumor types, none of the available normal tissues was methylated. This data suggests that met hylation of the CpG island and promoter of the RASSFIA gene is common not o nly in lung and breast tumors but also in renal cell carcinoma and ovarian cancer. (C) 2001 Wiley-Liss. Inc.