Tissue expression of the kallikreins examined to date appears to be down-regulated in aggressive forms of breast cancer (hK3 (PSA) (Levesque et al, 1998), hK10 (Liu et al, 1996; Goyal et al, 1998), hK13 (Yousef et al, 2000) and hK6 (Anisowicz et al, 1996)) and up-regulated in ovarian cancer (hK4 (Obiezu et al, 2002), hK10 (Luo et al, 2001), hK5 (Kim et al, 2001), hK8 (Magklara et al, 2001) and hK6 (Tanimoto et al, 2001)). Here, KLK6 is linked to ovarian carcinoma.