Triple‐negative breast cancer (TNBC) tends to have a very high STC1 level compared to normal tissues,56, 57 and ER‐positive tumours also possess a relatively higher STC1 expression level than normal,58, 59 whereas STC1 may be absent in BRCA1‐mutant breast tumours.53 This evidence concerns the gene BRCA1 and breast neoplasm.