The present invention provides a method for predicting therapeutic effects of chemotherapy on hepatocellular carcinoma patients who have been treated with transarterial embolization and an antitumor agent for treating cancer patients who have been predicted to have a high probability of obtaining sufficient therapeutic effects from such chemotherapy. The present invention also provides a method for predicting therapeutic effects of chemotherapy on hepatocellular carcinoma patients who have been treated with transarterial embolization using the expression level of PDGF-BB or IL-8 as an indicator and an antitumor agent for treating cancer patients who have been predicted to have a high probability of obtaining therapeutic effects by such prediction method.