- Effect of bacterial metabolism in the intestine on colorectal tumors induced by 1,2-dimethylhydrazine in transgenic mice harboring human prototype c-Ha-ras genes. Ohno, K., Narushima, S., Takeuchi, S., Itoh, K., Itoh, T., Hioki, K., Nomura, T. J. Exp. Clin. Cancer Res. (2001)