Prolonged survival of anaplastic thyroid carcinoma is associated with resectability, low tumor-infiltrating neutrophils/myeloid-derived suppressor cells, and low peripheral neutrophil-to-lymphocyte ratio.

In addition to traditional beneficial prognostic factors, e.g., surgical resection, factors attributed to resectability, and absence of co-existing RAS/BRAF and TERT promoter mutations, we herein show that tumor-infiltrating and circulating neutrophils/MDSC are adverse prognostic factors in ATC.