Fat Stem Cells for Breast Reconstruction Safe if Cancer is Dormant
In 2007, doctors in Japan discovered that adipose (fat cell)-derived stem cells showed promise for improving cosmetic outcomes of breast reconstruction following a mastectomy for breast cancer. However, research since has found that the stem cells may send “growth signals” that promote tumor reactivation if the patient’s cancer is still active. University of Pittsburgh School of Medicine has found that, if a patient’s cancer is dormant, the stem cells are safe and offer an alternative for reconstructive surgery.
Adipose Derived Stem Cells Not Recommended for Active Cancers
Fat tissue is extracted from the patient using standard liposuction (“tummy tuck”) procedures. Half of the tissue is processed for use as the primary filler tissue while the other half is processed by a method that extracts and concentrates regenerative cells, including a type of stem cell called induced pluripotent stem cell or iPS. These are added to the filler tissue by injecting them into the breast at locations determined by the individual patient’s reconstructive needs.
For the most recent study, funded in part by the National Institutes of Health, Vera S. Donnenberg PhD, assistant professor of surgery at Pitt School of Medicine, and colleagues collected adipose tissue from healthy patients undergoing liposuction by co-author J. Peter Rubin MD that would have otherwise been discarded.
The team isolated stem cells from adipose tissue (ADSC, or adipose derived stem cells) or bone marrow and added them to the collected fat tissue along with human breast cancer cells obtained directly from patients. After two weeks in a culture, the ADSC did greatly encourage the growth of the tumor cells, as expected.
In a follow-up experiment, the team combined ADSC, adipose tissue, and tumor cells deactivated with irradiation. The researchers found that the “resting” tumor cells were not affected by the injection of adipose derived stem cells.
“There is already some clinical evidence that breast reconstruction with transplanted fat is safe. Our findings lead us to conclude that augmentation of fat grafts with additional ADSC should be postponed until there is no evidence of active cancer,” Dr. Donnenberg said. “Our data in the mouse suggest that dormant cancer cells are not sensitive to the growth signals sent by the ADSC.”
The findings from the study are published in the journal Tissue Engineering Part A. Other resources for this article are from the journals Proceedings of the National Academy of Sciences and Breast Cancer Research and Treatment.