Cancer is a complex disease that is considered one of the leading causes of the world-wide death. Through genetic and/or epigenetic changes, cancer cells acquire many abnormal characteristics that trigger tumour growth, spread and avoidance of immunologic and therapeutic targeting. One of the key features that characterises many cancers is the re-activation of a group of genes that are normally only expressed during distinct developmental processes, including germline genes. Cancer/testis (CT) genes are a group of germline genes that have expression normally restricted to testicular germ cells but are aberrantly activated in a wide range of tumours. The activation of CT genes in cancer cells has been reported to contribute to oncogenic function. Given this, understanding this class of genes is important in the field of cancer biology. This current study focused on exploring the functional roles of two germ-cell specific genes that are activated in a variety of tumours, PRDM9 and TEX19.

PRDM9 is a histone methyltransferase activator of meiotic recombination hotspots. Its murine orthologue, Meisetz, activates meiotic recombination and acts as a transcriptional regulator for many meiosis genes. Human PRDM9 is a meiosis-specific gene that is normally expressed in the early stages of the meiotic prophase. Data obtained in this study suggests that human PRDM9 may influence cellular proliferation and acts as a transcriptional regulator for other germline genes in cancerous cells.

TEX19 is a mammalian specific gene. TEX19 plays important roles in pluripotency and the self-renewal potential of germ cells, although its exact function remains unclear. More recently, human TEX19 has been reported to potentially serve to maintain the proliferative state in cancer cells. In this study, we found that depletion of TEX19 had a significant influence on cancer cell proliferation. Furthermore, we suggest that TEX19 may regulate histone acetylation.