Published data show a low prevalence of c Kit expression in breast carcinomas, ranging from 1 to 13% (Tsuura et al, 2002; Nielsen et al, 2004; Simon et al, 2004; Tsuda et al, 2005; Reis-Filho and Tutt, 2008), and in one report up to 25% (Tsutsui et al, 2006). This evidence concerns the gene KIT and breast carcinoma.