- Kruppel-like factor 6 (KLF6) is a tumor-suppressor gene frequently inactivated in colorectal cancer. Reeves, H.L., Narla, G., Ogunbiyi, O., Haq, A.I., Katz, A., Benzeno, S., Hod, E., Harpaz, N., Goldberg, S., Tal-Kremer, S., Eng, F.J., Arthur, M.J., Martignetti, J.A., Friedman, S.L. Gastroenterology (2004)