Of interest, kallikrein 6 (also known as zyme/protease M/neurosin) and kallikrein-10 (NES1), two serine proteases recently shown to be present at high levels in the circulation of a subset of ovarian cancer patients (Diamandis et al, 2003; Luo et al, 2003), were both highly differentially expressed genes in USPC when compared to NEC. Here, BMP4 is linked to ovarian cancer.