Despite the distinct anatomical origins and histopathological divergence among various NE cancers, GALNT9‐mediated ANXA2 O‐GalNAc acts as a pan‐cancer mechanism to trigger MBL complement activation, coagulation, and thrombus formation, thus promoting liver metastasis of NE malignancies, including NEPC, SCLC, and neuroendocrine colon cancer. Here, ANXA2 is linked to small cell lung carcinoma.