KLK1/tissue kallikrein is a member of a family of structurally related serine proteases which exhibit a diverse range of enzymic activities. Other members of this family of genes and the bradykinin (B2) receptor have been implicated in cancer processes. The KLK genes are expressed in various organs of the reproductive tract, including the prostate and uterus. In this study, we have examined whether KLK1/tissue kallikrein and the B2 receptor were both expressed in cancers emanating from these organs. We have shown that KLK1/tissue kallikrein and the B2 receptor are expressed, to varying degrees, in prostate disease and 2 human prostate cancer cell-lines, LNCaP and DU145. KLK1 is also expressed in a range of endometrial cancers, although at lower levels than that observed for normal human endometrial tissues. These findings suggest that a functional kallikrein-kinin system is present in prostate disease, in particular, which may be important in the process of tumorigenesis in this tissue.