Characterization of tumor infiltrating Natural Killer cell subset

The presence of tumor-infiltrating Natural Killer (NK) within a tumor bed may be indicative of an ongoing immune response toward the tumor. However, many studies have shown that an intense NK infiltration, is associated with advanced disease and may even facilitate cancer development. The exact role of the tumor infiltrating NK cells and the correlation between their presence and poor prognosis remains unclear. Interestingly, during pregnancy high numbers of a specific NK subset, CD56^brightCD16^dim, are accumulated within first trimester deciduas. These decidual NK (dNK) cells are unique in their gene expression pattern secret angiogenic factors that induce vascular growth. In the present study we demonstrate a significant enrichment of a CD56^brightCD16^dim NK cells within tumors. These NK cells express several dNK markers including VEGF. Hence, this study adds new insights into the identity of tumor residual NK cells, which has clear implications for the treatment of human cancer.