Expression of genes involved in prognostic NK signature. A) Unsupervised clustering based on genes involved in NK cell activation and interaction with tumour cells. B) Similarity matrix based on Pearson correlation assayed on a total of 15 including genes associated with NK, NKT and genes previously identified to predict breast cancer patients’ clinical outcome genes . Genes previously identified are indicated with *. C) Principal Component Analysis based on 15 genes evaluated in 1B comparing relapse-free (red colour) and progressing (blue colour) patients.