Tumour-suppressive TANs identified in humans

Tumour-associated neutrophils (TANs) can be detected in the microenvironment of most tumours; however, the role of these cells has yet to be established. Now, an in vitro analysis of tumour biopsy and blood samples from patients with stage I–II lung cancer has identified a subset of TANs with a tumour suppressive role. These TANs expressed cell-surface proteins more typically observed on antigen-presenting cells (APCs), that were not detectable on neutrophils in patients' peripheral blood samples. An antigen-presenting role of APC-like TANs was then confirmed by the ability of these cells to trigger memory T-cell responses to HLA class I and class II epitopes. These cells were most commonly observed in the microenvironment of tumours <3 cm in diameter, but were absent in patients with tumours >7 cm, suggesting that APC-like TANs have a tumour suppressive effect.