Breast cancer is the most common
cancer that causes death in women. Conventional
therapies, including surgery and
chemotherapy, have different
therapeutic effects and are commonly associated with risks and side effects. Near infrared radiation is a technique with few side effects that is used for
local hyperthermia, typically as an adjuvant to other
cancer therapies. The understanding of the use of near NIR as a monotherapy, and its effects on the immune cells activation and infiltration, are limited. In this study, we investigate the effects of HT treatment using NIR on
tumor regression and on the immune cells and molecules in
breast tumors. Results from this study demonstrated that local HT by NIR at 43 °C reduced
tumor progression and significantly increased the median survival of
tumor-bearing mice. Immunohistochemical analysis revealed a significant reduction in cells proliferation in treated
tumor, which was accompanied by an abundance of
heat shock protein 70 (Hsp70). Increased numbers of activated dendritic cells were observed in the draining lymph nodes of the mice, along with infiltration of T cells, NK cells and B cells into the
tumor. In contrast,
tumor-infiltrated regulatory T cells were largely diminished from the
tumor. In addition, higher IFN-γ and
IL-2 secretion was observed in
tumor of treated mice. Overall, results from this present study extends the understanding of using local HT by NIR to stimulate a favourable immune response against
breast cancer.