IL6 and lung cancer: No publication bias was detected for association between IL-6 rs1800796 polymorphism and risk of lung cancer under all genetic models using the Begg’s test (P = 0.133 for homogeneous co-dominant model; P = 0.230 for heterogeneous co-dominant model; P = 0.230 for dominant model; P = 0.230 for recessive model; P = 0.368 for allelic model).