[The expression of thymidylate synthase and thymidine phosphorylase in the early-stage of gastric cancer].

The immunohistochemical expression of thymidylate synthase (TS) and thymidine phosphorylase (TP) was investigated in 116 of early gastric cancer, in order to know whether or not these reflect malignity in an early stage. The materials conditioned on early gastric cancer with submucosal invasion and over 1 cm2 in size, were 57 with and 59 without lymph node metastasis. They were divided into two by the depth of invasion. The expressions of TS and TP in these group were compared with corresponding histopathological findings. Overall expressions of TS and TP were 54.3% and 34.5%, respectively. The TS-expression was not related with the depth of invasion and lymph node metastasis. The TP-expression, however, showed significant difference between with and without lymph node metastasis, and was so on the depth of submucosal invasion in the group without the nodal metastasis. Multivariate analysis showed that mucosal spread bordering 4 cm2 in size (p = 0.024) and lymphatic permeation (p = 0.099) in TS-expression, and lymph node metastasis (p = 0.041), submucosal invasion (p = 0.076) and venous permeation (p = 0.111) in TP-expression were the noticeable factors regarding to their high expression rates. Although these results were considered not to exceed gastric resection on the prognosis, they might be applicable as one of the indicators in postoperative follow-up on the minor resection of early gastric cancer such as EMR or local resection.