Hyperthermia therapy not only raises immune system function in general, but an accumulating body of evidence suggests that a more active immune system is the precise catalyst needed for shrinking tumors. This makes total sense. Cancer tissue must live in an acidic pH environment and raising temperature will raise pH as well, creating an inhospitable environment for cancer cells to grow. A 2013 study published in the journal Cancer Immunology Research was able to pinpoint some precise mechanisms through which heightened temperature can lead to apoptosis or “programmed cell death” in cancer cells. Researchers found that “hyperthermia impact(s) the tumor microenvironment through temperature-sensitive check-points that regulate tumor vascular perfusion, lymphocyte trafficking, inflammatory cytokine expression, tumor metabolism, and innate and adaptive immune function”. 2014 study done in Korea found that inducing a hyperthermic condition of 105 degrees F (42 degrees C) was toxic not only to regular breast cancer cells, but breast cancer stem cells as well.