Five KLKs predict favorable prognosis (KLK3, 9, 12, 13 and 15), four indicate unfavorable, poor prognosis (KLK5, 7, 10 and 14).5,12,72 KLK3 and KLK10 are also predictive markers of response to endocrine therapy.48,73,74 Furthermore, breast cancer risk is associated with presence of single nucleotide polymorphisms (SNP) of KLK2 (Ex5 þ 118C>T) or KLK4 (4207C>G).75 No data are available regarding any possible prognostic/predictive value of KLK1, 2, 4, 6, 8 and 11 in breast cancer. Here, KLK4 is linked to breast cancer.