Epsin 3 is a 632 amino acid member of the epsin protein family. Epsin 3 localizes mainly to the perinuclear region of the nucleus and in clathrin-coated vesicles close to the cell periphery. Epsin 3 is expressed in migrating keratinocytes from wounded skin, but not in normal skin or differentiating keratinocytes. Epsin 3 contains one ENTH (epsin N-terminal homology) domain and two UIM (ubiquitin-interacting motif) repeats and is expressed as two isoforms produced by alternative splicing. The gene that encodes epsin 3 maps to human chromosome 17, which comprises over 2.5% of the human genome and encodes over 1,200 genes. Two key tumor suppressor genes are associated with chromosome 17, namely, p53 and BRCA1. Tumor suppressor p53 is necessary for maintenance of cellular genetic integrity by moderating cell fate through DNA repair versus cell death. Malfunction or loss of p53 expression is associated with malignant cell growth and Li-Fraumeni syndrome. Like p53, BRCA1 is directly involved in DNA repair, specifically it is recognized as a genetic determinant of early onset breast cancer and predisposition to cancers of the ovary, colon, prostate gland and fallopian tubes.