Although no data was provided on the intrinsic breast cancer subtypes recruited, since all patients within their cohort were ER-negative, it could be inferred that their breast cancer markers expression patterns could theoretically be: “ER-/PR-/HER2+”, “ER-/PR-/HER2-“, “ER-/PR+/HER2+” or “ER-/PR+/HER2-”. This evidence concerns the gene ESR1 and breast cancer.