Numerous studies have also shown that basal-like breast cancer can be specifically identified using IHC surrogate panels including ER, PR and HER2 negativity and either EGFR or CK5/6 positivity (ER-, PR-, HER2-, CK5/6+ and/or EGFR+)[8,19,26,43,44]. The gene discussed is ESR1; the disease is breast carcinoma.