Interferon-Beta Gene Transfer (Ad.hIFN-β) as Treatment for Refractory Colorectal Carcinoma With Liver Metastases

This study will be conducted in subjects with refractory colorectal carcinoma with unresectable liver metastases. The purposes of the study are: * to evaluate the safety and any harmful effects of an intravenous injection of Ad.hIFN-β; * help determine whether the virus carrying the interferon-beta gene will enter the bloodstream and liver tumor cells and cause the cancer cells to die.