Furthermore, both NOD1 and NOD2 were overexpressed in embolic tumor cells resulting from lymph-vascular space invasion (LVSI) compared to the primary tumors without LVSI (P < 0.05, Fig. 1G), whereas significantly higher expression of NOD1 was detected in the CSCC tissues of patients with lymph node metastasis (LM) relative to the non-LM samples (P < 0.05, Fig. 1H). Here, NOD1 is linked to metastatic malignant neoplasm in the lymph nodes.