Cells that facilitate tumour growth identified

A recent study has identified the population of white blood cells that tumours use to enhance growth and suppress the disease-fighting immune system. The results mark a turning point in cancer immunology and provide the foundation for developing more effective therapies.

It was known earlier that a diverse group of white blood cells called myeloid-derived suppressor cells (MDSC) are more abundant in cancer patients than in healthy individuals. "We have identified the monocytic cells as the important cell to target, not only in cancer but possibly for treatment of autoimmune disorders like rheumatoid arthritis or inflammatory bowel diseases where dampening the immune response could provide relief," said Peter Murray from St Jude Children's Research Hospital, US.

The cells enhance cancer growth and suppress the specialised T cells that target and destroy tumour cells. Blocking T cells is one of the main MDSC functions. Working in mouse models of cancer, researchers showed immune suppression associated with MDSCs is primarily the work of a type of white blood cells called monocytes.

"We also identified growth factors and other molecules essential to the survival and function of these monocytic cells. Targeting these molecules could lead to more precise approaches for controlling the immune response at the tumour site," explained Murray.

Their studies provided insight into regulation of two forms of programmed cell-death pathways known as apoptosis and necroptosis. "This study marks a significant step in efforts to understand, develop and optimize immunotherapies for treatment of cancer," Peter Murray concluded. (The study appeared in the journal Immunity)