It has been confirmed that exogenous HA may serve as a radioprotective agent through TLR4 interaction in the intestine, that the HA molecule after IR exposure maintained antioxidant activity, that it significantly reduced radiation-induced inflammation and affected tissue hydration in patients with pelvic radiotherapy, and, in one study, that it improved radiation dermatitis (Liguori et al., 1997; Kim et al., 2008; Riehl et al., 2012; Cosentino and Piro, 2018). The gene discussed is TLR4; the disease is radiodermatitis.