Next, to test the causal role of transcription elongation defects in the resistance to immune checkpoint inhibitor therapy in vivo, we injected control and flavopiridol pre-treated CT26 colon carcinoma lines into immune-competent Balb/c mice, and measured tumor growth after treatment with the control IgG or anti-CTLA4 antibodies. The gene discussed is CTLA4; the disease is colon carcinoma.