These findings bear out that nonsteroidal anti-inflammatory drugs such as aspirin (Baron et al, 2003) or selective inhibitors of cyclooxygenase-2 (COX-2) (Steinbach et al, 2000) interfere with colorectal malignancies, that selective oestrogen receptor modulators such as tamoxifen can prevent breast cancer (Fisher et al, 1998) and that the α-reductase inhibitor finasteride can delay the onset of prostate cancer (Thompson et al, 2003). Here, PTGS2 is linked to breast cancer.