We previously undertook a systematic evaluation of the semi-quantitative IHC expression of ER, PgR, HER2, Ki67 and the phosphorylated proteins pAKT and pERK1/2 in core-cut and excision specimens from primary breast cancer since clinical management involves assessment of both type of samples and particularly in clinical trials, a comparison between the two [14]. This evidence concerns the gene MKI67 and breast cancer.