We used MCF10A cells, a spontaneously immortalized, non-malignant cell line obtained from a patient with fibrocystic disease [32], and stably infected them with EGFR-wild type (WT), EGFR-G719S (GS) or EGFR-DEL (E746-A750) (DEL) retroviral constructs. Here, EGFR is linked to breast fibrocystic disease.