The discrepancies in miRNA expression observed from these studies may be contributed by the different types of ovarian tissue samples used (fresh samples, FFPE and cells); histological subtypes of epithelial ovarian cancer included in the study (serous, endometrioid, mucin and clear cell); the profiling platforms used (qPCR, microarray and deep sequencing) and the normal tissues used as controls (whole normal ovary and normal ovarian surface epithelial cells). The gene discussed is MUC5AC; the disease is ovarian carcinoma.