Abstract: The bone marrow-derived Langerhans cells (LC) are antigen-Presenting accessory cells functioning as part as the immune system and relate to tumors to a certain extent' In the presentstudy, the quantitative analysis of LC invasion in sixty five tissues of gastric cardnoma was carried out with immunohistochemistry method to probe the relationship b et ween LC invas ion andmetastasis and differentiation of tumors. The results showed that the markedly invasion of LCwas observed in the tissues from the patients without cancer metastasis in the regional lymphnodes; LC invasion was seen in all of 35 ti88ues from the patients without the metastasis, but only9 out of 32 samples from the patients with the metastasis. In addition, the significant LC invasioncould be observed a18o in 15 of 15 well differentiated cancer tissues and 14 of 18 moderately differentiated, but only 5 out of 32 poorly differentiated. The results suggested that LC invasion incancer tissues relates to the metastasis and differentiation of gastric carcinoma significantly.