Y Chromosome Loss and Implications for Oncology.

Abstract

The Y chromosome has recognized functions in promoting male sex determination and regulating aspects of fertility. However, recent work has demonstrated important roles for the Y chromosome and Y-encoded genes in multiple domains of male health, including cancer. It is well-established that males experience shorter life spans than females, and this sex bias on overall mortality is ac-centuated in populations with longer life expectancy, in part related to elevated rates of cancer. The majority of human malignancies exhibit a sex bias with elevated frequencies in males. For many of these cancer types, the disparity has not been explained by environmental risk factors such as tobacco use. Notably, loss of the Y chromosome (LOY) detected in blood cells, termed mosaic LOY (mLOY) is a common event that is related to advancing age and is associated with a shortened lifespan. mLOY is linked to increased incidence and mortality across a range of malignancies. Further, tumors arising in different anatomic sites exhibit different frequencies of partial or complete Y chromosome loss. Causal oncogenic or tumor suppressive roles have been documented for several Y-encoded genes, such as KDM5D, that exert pleiotropic effects on cellular functions by virtue of genome-wide regulation of gene activity. In this review, we discuss aspects of the Y chromosome relevant to oncology. The recent completion of the entire human Y-chromosome sequence provides a reference map of Y-encoded genes and regulatory elements to enable causal molecular studies that may explain and exploit the marked disparity in male cancer risk and mortality.