Epigenetic inactivation of the hsa-miR-203 in haematological malignancies.

miR-203 is a tumour suppressor microRNA (miRNA). We studied the methylation of hsa-miR-203 in 150 samples including acute myeloid leukaemia (AML), acute lymphoblastic leukaemia (ALL), chronic myeloid leukaemia (CML), chronic lymphocytic leukaemia (CLL) and non-Hodgkin's lymphoma (NHL) by methylation-specific PCR, and miRNA expression by stem-loop RT-qPCR. hsa-miR-203 promoter was unmethylated in normal controls but homozygously methylated in two AML and four lymphoma cell lines, in which 5-Aza-2'-deoxycytidine treatment led to promoter demethylation and miR-203 re-expression.