MCF7 breast tumor cells were submitted to four experiments: in serum free medium (SFM) without fibronectin (mock); treated with 5-aza-2′-deoxycytidine (5-Aza-treated) for seven days; in SFM containing fibronectin (FN) for five hours (FN-treated); and FN-treated cells were transferred to new culture dishes and maintained in SFM in culture for additional 48 hours without fibronectin (recultured cells). The gene discussed is FN1; the disease is breast neoplasm.