Notably, it was found that treatment by TKIs such as gefitinib could lead to an obvious decrease in IL-6 in the patients [73]; in addition, such treatment could also shift a portion of patients with high counts of CTCs into low ones, which could have a significantly prolonged PFS [74], which is a surrogate for OS in NSCLC [75]. This evidence concerns the gene IL6 and non-small cell lung carcinoma.