Immune cells open window to breast cancer risk

September 19th, 2013

NBCF funding has led to a major discovery highlighting the important role played by immune cells in the risk of developing breast cancer and how women may be more vulnerable to breast cancer at certain times in their menstrual cycle.

Adelaide researchers have focused their efforts on a specific type of immune cell known as macrophages, and how the function of these cells in the breast changes due to fluctuations in hormones during the menstrual cycle.

The results of laboratory studies – published online ahead of print in the journal Biology of Reproduction – show that while macrophages play a role in the normal function of the breast, at certain stages in the menstrual cycle they may make the breast more susceptible to cancer.

Wendy IngmanLead author of the study, Associate Professor Wendy Ingman, an NBCF Fellow, said these cells should protect our body from cancer, but at certain times of the month it appears macrophages might allow cancerous cells to escape immune system detection.

“It’s sort of a Jekyll and Hyde scenario – we need the macrophages to do their job so that the breast can function normally, but at the same time they’re giving cancerous cells the chance to survive,” said Associate Professor Ingman, who is Head of the Breast Biology and Cancer Unit with the University of Adelaide’s School of Medicine, the Robinson Institute and the Queen Elizabeth Hospital.

“We think there is a window of risk that opens up around the time when women have their period. This is when levels of the hormone progesterone drop, and this affects how the breast functions. At this time, immune defences in the breast tissue are down and women could be more susceptible to the initiating factors that lead to breast cancer,” she said.

Associate Professor Ingman said researchers had known for some time that there is a link between the number of years of menstrual cycling and breast cancer risk.
“We’re now starting to understand the cell-to-cell interactions that are impacting on this risk,” she said. “One in eight Australian women will be diagnosed with breast cancer during their lifetime. By better understanding the biological factors that underpin breast cancer susceptibility, we might one day be able to close these windows of risk, and reduce women’s lifetime risk of breast cancer.”

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This study was funded by NBCF and the National Health and Medical Research Council.