Importantly, knock-down of p27 in SK-BR-3 cells increased ERK1/2 phosphorylation (Figure S4D) and low cytoplasmic p27/stathmin ratio was significantly associated with a higher level of ERK1/2 phosphorylation in primary breast carcinomas (Supplementary Table S1 and Supplementary Figure S4E). This evidence concerns the gene CDKN1B and breast carcinoma.