TFF1 is an oestrogen-responsive gene (Masiakowski et al. 1982, May & Westley 1986, 1988) that has utility as a marker of hormonal response in breast cancer patients, but it has not found widespread use (Foekens et al. 1990, Henry et al. 1990, 1991, Schwartz et al. 1991, Spyratos et al. 1994, Soubeyran et al. 1996). Here, TFF1 is linked to breast cancer.