Tumor-associated neutrophils (TANs) as prognostic markers in colorectal cancer: A brief review

Neutrophils are cell protagonists of innate immunity, frequently found in the tumor microenvironment and associated with higher tumor stage and adverse prognosis of patients, especially in hepatocellular, renal cell, pancreatic ductal, and non-small cell carcinomas. The aim of the present review is a systematic appraisal of current literature to examine the prognostic role of tumor-associated neutrophils (TANs) in patients operated for colorectal cancer. We analyzed 9 articles (number = 4606 patients). Although a noteworthydegree of heterogeneity was found in terms of study methodology, 8 out of 9 articles surprisingly showed an improved survival in colorectal cancers with high TAN counts. These data suggest that TANs may be favorable prognostic markers in colorectal cancer. Therefore, there is need for standardization of TAN assessment that will help in more accurately predicting prognosis in patients with colorectal cancer.