IRF1 and colon carcinoma: To test our hypothesis, HT29 human colon carcinoma cells and CT26.WT mouse colon carcinoma cells were cultured and treated with different concentrations (20, 40, 60, 80, and 100 ng/mL) of recombinant human IFN-γ and recombinant murine IFN-γ, respectively, for 48 h; after which, the expression levels of IRF-1 and IRF-2 mRNA were detected by quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR) (Fig. 2b).