Natural killer cells from malignant pleural effusions show a decidual-like, pro-angiogenic phenotype

Natural killer (NK) cells are lymphoid cells involved in tumor recognition and eradication. NK activity is impaired in cancer patients and in non-small cell lung cancer showed a pro-angiogenic phenotype and function. We investigated whether NK cells infiltrating malignant pleural effusions (mPE) from subjects with primary or metastatic tumors are able to acquire pro-angiogenic features. NK cells from mPE display pro-angiogenic features and mPE-CM was able to polarize in vitro healthy PB NK cells towards the pro-angiogenic CD56brightCD16- NK subset, suggesting that in the mPE milieu, diverse soluble factors are able to skew cytotoxic NK cells into pro-tumor, pro-angiogenic NK cells.