Abstract: For stage Ⅱ colon cancer patients after surgery，the benefit of adjuvant chemotherapy remains controversial. Several studies indicate that the patients with high-risk stage Ⅱ colon cancer can benefit from adjuvant chemotherapy after surgery. According to the clinical and pathological features, the stage Ⅱ colon cancer patients including T₄ lesion, perforation, peritumoral lymphovascular invasion can benefit from the adjuvant chemotherapy of oxaliplatin. In the horizontal of molecular and genetic levels, the stage Ⅱ colon cancer patients can express high microsatellite instability (MSI-H) and cannot benefit from the chemotherapy of Fluorouracil. The guiding functions of 18q loss of heterozygosity (18q LOH), Cx43 and gene expression profiling in adjuvant chemotherapy are still unclear, and need further study.

Key words: Colonic neoplasms, Microsatellite instability, Loss of heterozygosity