Reduced expression of intercellular adhesion molecule-1 in ovarian adenocarcinomas

Ovarian adenocarcinomas develop as the result of multiple genetic, and epig enetic changes in the precursor ovarian surface epithelial (OSE) cells whic h result in a malignant phenotype. We investigated changes in gene expressi on in ovarian adenocarcinoma using a cDNA array containing 588 known human genes. We found that intercellular adhesion molecule-1 (ICAM-1) was express ed at lower levels in the ovarian tumour cell lines OAW42, PEO1 and JAM tha n in the immortalised human ovarian surface epithelial cell line HOSE 17.1. Further investigation revealed ICAM-1 was expressed in the surface epithel ium of normal ovaries and both mRNA and protein expression levels were redu ced in the majority of ovarian adenocarcinoma cell lines and primary tumour s. ICAM-1 expression was increased in 8/8 cell lines treated with the de no vo methyltransferase inhibitor 5-aza-2'-deoxycytidiine, indicating that met hylation of CpG islands may play a role in the down-regulation of its expre ssion in primary tumours. 'There was a significant association between pati ents whose tumours expressed ICAM-1 and survival (P = 0.03), suggesting tha t expression levels of ICAM-1 may have clinical relevance. (C) 2001 Cancer Research Campaign.