A new study led by scientists in the Center for Cancer Research (CCR) at the National Cancer Institute (NCI) sheds light on one way tumors may continue to grow despite the presence of cancer-killing immune cells. The findings, published March 29, 2019, in Science, suggest a way to enhance the effectiveness of immunotherapies for cancer treatment. NCI is part of the National Institutes of Health..

Dying cancer cells release the chemical potassium, which can reach high levels in some tumors. The research team reported that elevated potassium causes T cells to maintain a stem-cell-like quality, or “stemness,” that is closely tied to their ability to eliminate cancer during immunotherapy. The findings suggest that increasing T cells’ exposure to potassium—or mimicking the effects of high potassium —could make cancer immunotherapies more effective.