Neutrophils
Neutrophils which are the largest number of immune cells in humans have always been considered as uncomplicated front-line troopers of the innate immune system. Recently, studies have found that neutrophils are associated with anti-tumor immune response[79]. Several studies have found that a low neutrophil-to-lymphocyte ratio was a good prognostic factor in EGFR mutant NSCLC patients receiving EGFR-TKIs treatment[80-82]. Another study found that intratumoral neutrophil density was lower in EGFR mutant NSCLC comparing with non- EGFR mutant NSCLC[83]. At present, there are few studies on the relationship between neutrophils and EGFR-TKIs resistance mechanism. Whether neutrophils are related to EGFR-TKIs resistance needs further study.