First, two cell lines representative of two different types of breast cancer, MDA-MB-231 (triple negative) and T47D (Luminal A) were incubated for 2 min with fluorescently labeled Tf (green), chased for 2–5 min to label EE, and then subjected to immunofluorescence against DMT1 (red), and Tom20 (magenta), a marker of the OMM. This evidence concerns the gene TOMM20 and breast cancer.