This study will assess the safety and efficacy of the administration of adenoviral vector expressing the human-reduced expression in immortalized cells (Ad-REIC) to a liver tumor in patients with hepatocellular carcinoma (HCC) or liver metastasis of pancreatic cancer. A Phase I clinical study of Ad-REIC administration to a liver tumor in a patient with HCC or liver metastasis of pancreatic cancer will be conducted. The study is a single-arm, prospective, nonrandomized, noncomparative, open-label, single-center trial performed in Okayama University Hospital, Okayama, Japan. Ad-REIC will be injected into the liver tumor under ultrasound guidance. Ad-REIC administration will be repeated a total of three-times every 2 weeks. The primary end point is the dose-limiting toxicity and incidence of adverse events. The secondary end points are the objective response rate and disease control rate. This study aims to expand the indication of Ad-REIC by assessing its safety and efficacy in patients with HCC or liver metastasis of pancreatic cancer.