CLINICAL-SIGNIFICANCE OF DENDRITIC CELL INFILTRATION IN ESOPHAGEAL SQUAMOUS-CELL CARCINOMA

We investigated the clinicopathological significance of dendritic cell infiltration (DCsI) in esophageal squamous cell carcinoma and in regi onal lymph nodes of 88 patients. The expression of mutated p53 protein and the degree of positive cancer cells of proliferating cell nuclear antigen (PCNA labeling index) in tumors were analyzed as biological m arkers. These factors were compared with the degree of DCsI in tumors and in lymph nodes. The number of dendritic cells (DCs) were counted a nd scored as per mm(2) in each case. The degree of DCsI of tumors with expression of p53 (19/mm(2), n=50) was significantly lower than that of DCsI in 38 tumors without expression of p53 (27/mm(2), P=0.0411). H owever, no significant correlation was detected between the PCNA label ing index and the degree of DCsI in 88 primary tumors (P=0.1273). The degree of DCsI in 53 metastatic lymph nodes (30/mm(2)) was significant ly lower than that of DCsI in 264 cancer-free regional lymph nodes (48 /mm(2), P=0.02). Although the degree of DCsI in tumors was not an inde pendent prognostic factor for the 78 surviving patients (P=0.2647), th e 3-year survival rate of patients in stage III and IV who underwent c urative operation and who had tumors with high DCsI (>9/mm(2), n=16, 7 2%) was significantly higher than that of the 24 patients who had tumo rs with low DCsI (less than or equal to 9/mm2, 21%, P=0.008). These fi ndings indicate that DCs infiltrated in and around the esophageal canc er may play a defensive role of the hosts against the tumors. This imm une defense of the hosts might be an important prognostic factor for p atients with advanced esophageal cancer. However, cancer cells which e xpress a mutated p53 protein might regulate the function or activity o f DCs.