Therefore, in addition to patients who have already developed sarcopenia prior to RT, patients at high risk of sarcopenia after RT—that is those of older age, with Child-Pugh classification B or C, higher AFP and PIVKA-II, larger PTV, and poor prognostic factor of HCC—also need intensive nutritional support during RT to prevent the development of sarcopenia after treatment. The gene discussed is AFP; the disease is sarcopenia.