We found increased mRNA expression of several mucin genes in ovarian clear cell carcinoma patients (n = 11), when compared to HGSOC (n = 10), including MUC2, MUC4, MUC6, MUC7, MUC12, MUC13, MUC17, MUC19, MUC21. This evidence concerns the gene MUC4 and ovarian clear cell cancer.