EGFR and breast neoplasm: In addition, 5 out of 7 and 4 out of 7 basal-like tumours showed respectively EGFR and CK5/6 overexpression compared to only 3 out of 52 and 5 out of 52 in the non-basal-like breast tumours (Pearson χ2, respectively P<0.0001 and 0.001).