To identify the factors contributing to the aggressive phenotype of IBC cells, we measured the expression of IFITM1, an ISG linked to tumor progression, in three IBC cell lines: triple-negative SUM149, HER2-amplified SUM190 and MDA-IBC-3, and the non-IBC cell line MCF-7 (ER+). The gene discussed is ESR1; the disease is neoplasm.