TLR4 and lung cancer: Numerous publications demonstrated that the existence of single nucleotide polymorphism (SNPs) made it possible for affecting TLR4 signaling, which was responsible for hyporesponsiveness and infection of fungus, virus and bacteria and the expression of TLR4 had a close association with the development of breast cancer [11–14], lung cancer [15], prostate cancer [16–21], colorectal cancer [22–26] and liver cancer [25, 27–29].