IFNG and colon carcinoma: Furthermore, a direct interaction between 5-FU and IFN-γ was observed by in vitro analyses that showed sensitization of human colon carcinoma cell lines to 5-FU that was induced by the cytokine through modulation of the expression of specific genes involved in apoptosis regulation (Adachi et al., 1999; Schwartzberg et al., 2002).