ST7 is a metazoan protein that behaves as a tumor suppressor in human cancer cells. It appears to localize to the cytoplasm and plasma membrane, and may mediate tumor suppression by regulating genes that are involved in oncogenic pathways and/or maintain cellular structure. It has been suggested that the suppression of tumorigenicity is associated with a function in mediating the remodeling of the extracellular matrix. However, somatic mutations of ST7 have not been observed as being commonly associated with molecular pathogenesis in various human neoplasias.