- Polymorphism in the thymidylate synthase promoter enhancer region is not an efficacious marker for tumor sensitivity to 5-fluorouracil-based oral adjuvant chemotherapy in colorectal cancer. Tsuji, T., Hidaka, S., Sawai, T., Nakagoe, T., Yano, H., Haseba, M., Komatsu, H., Shindou, H., Fukuoka, H., Yoshinaga, M., Shibasaki, S., Nanashima, A., Yamaguchi, H., Yasutake, T., Tagawa, Y. Clin. Cancer Res. (2003)