PTK6 and breast cancer: Overall survival analysis of breast cancer patients’ samples from the TCGA data set revealed that: 1) ER-positive breast cancer patients have a better prognosis than all the other subtypes combined (n = 1102; P = 6.3e-07; Additional file 2: Figure S3A); 2) high BRK levels in the breast in breast cancer patients tend to be associated with shorter overall survival than patients with low BRK levels (n = 1102; P = 0.65; Additional file 2: Figure S3B); 3) high BRK levels in ER-positive tumors is associated with shorter overall survival, (n = 491; P = 0.84; Additional file 2: Figure S3C).