GATA factors comprise a small family of transcription regulatory proteins containing two conserved zinc finger DNA binding domains for the consensus sequence (WGATAR). Among the six GATA factors, GATA-1/2/3 factors are prominently expressed in the hematopoietic cell lineage, while GATA-4/5/6 factors show a partly overlapping expression pattern in the heart and endoderm-derived organs. We previously reported that GATA4 and GATA5 were silenced by their promoter hypermethylation in gastrointestinal, lung and ovarian cancers. However, it remains unknown the mechanism underlying loss of GATA transcription factors in gastric carcinogenesis. To clarify the role of GATA, we examined GATA4/5 methylation and their downstream target genes in gastric cancer (GC). By using methylation specific PCR, the methylation frequency of GATA5 (30, 39%) was significantly higher than that of GATA4 (10, 13%) in 77 GC tissues (P Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 200.