In Lebeau study [25], the lack of active matriptase on SK-BR-3 breast cancer cells was consistent with their hypothesis that low expression of matriptase and the ratio of matriptase relative to HAI-1 favors matriptase inhibition, however, the low matriptase expression in their SK-BR-3 cells suggests that either they are different from the ones we are using and those used by Welman et al [47]. This evidence concerns the gene SPINT1 and breast carcinoma.