Among the three genes shared by all signatures, two have already been applied for tumor subtyping, i.e., ESR1 is the primary marker classifying breast tumors into ER positive and ER negative subgroups and KRT17 plays crucial roles in differentiating the basal-like subtype from the other triple negative tumors, indicating that FOXA1 may be a novel immunohistochemistry marker for breast tumor classification. The gene discussed is ESR1; the disease is neoplasm.