Examination of possible correlations between acute GU toxicity grade, acute GI toxicity grade, fatigue score, and serum concentrations of IL-6 and TGF-β1 after the 25th fraction in patients with prostate cancer treated with radiotherapy, showed a significant positive association between GU toxicity grades after the 25th fraction and fatigue scores after the 25th fraction (p = 0.009), as presented in Table 7. The gene discussed is IL6; the disease is prostate carcinoma.