The results of the meta-analysis showed significant associations between high Ki-67 expression and being male, smoking habits, being a non-ADC patient, higher tumor stage (T2-4) and poorer differentiation grade (moderate or poor); the combined ORs and 95 % CIs were as follows: OR 1.89, 95 % CI 1.53–2.33, P < 0.001; OR 2.20, 95 % CI 1.72–2.82, P < 0.000; OR 1.88, 95 % CI 1.60–2.22, P < 0.001; OR 1.46, 95 % CI 1.13–1.88, P = 0.004; and OR 1.47, 95 % CI 1.15–1.88, P = 0.002, respectively. Here, MKI67 is linked to neoplasm.