Tumor infiltrating dendritic cells predict treatment response to immmunotherapy in patients with metastatic renal cell carcinoma.

BACKGROUND Although renal cell carcinoma (RCC) is considered to be an immunogenic tumor, the role of immunogenicity in this tumor for predicting treatment response has been little investigated. PATIENTS AND METHODS Resected RCC specimens from 25 patients who received cytokine treatment for metastases were investigated using immunohistochemistry for CD83+ or S100+ dendritic cells (DCs), CD8+ T-cells, HLA-DR+ tumor cells, CD68+ tumor associated macrophages, microvascular density and vascular endotherial growth factor. RESULTS Among the examined parameters, DCs status showed predictive value, that is, higher numbers of CD83+ or S100+ cells in tumors were associated with favorable treatment response. However, only higher CD83 status, which indicates mature and activated DCs, contributed to better survival (p = 0.0339). CONCLUSION Increased tumor infiltration of mature DCs would be a predictor of treatment response and outcome in metastatic RCC patients, who receive immunotherapy.