The tetraspanins are integral membrane proteins expressed on cell surface and granular membranes of hematopoietic cells and are components of multi-molecular complexes with specific integrins. Oculospanin, also known as tetraspanin 10 (TSPAN10) or OCSP, is a 355 amino acid multi-pass membrane protein belonging to the tetraspanin (TM4SF) family. Oculospanin is expressed in certain regions of the eye such as retinal pigment epithelium, ciliary body and iris, but is not found in the lens. The gene encoding Oculospanin 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. 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, and is liked to predisposition of cancers of the ovary, colon, prostate gland and fallopian tubes.