HIF1A and metastatic malignant neoplasm in the lymph nodes: When stratifying for the lymph node status of gastric cancer, the results showed that overexpressed HIF-1α was significantly associated with lymph node metastasis in 11 studies (1415 patients; OR  = 3.486, 95% CI  = 2.737 –4.440, P<0.001), with low heterogeneity among studies (I2 = 31.4%, subgroup difference P = 0.148) (Table 2).