Ang-2 expression had a significant relationship with lymphatic invasion in NSCLC patients [28, 31, 40, 41, 43, 44], with the pooled OR of 3.15 (95 % CI: 1.97–5.03, p = 0.000 and I2 = 26 %). This evidence concerns the gene ANGPT2 and non-small cell lung carcinoma.