ANGPT2 and head and neck squamous cell carcinoma: The gene most correlated was ANGPT2 (angiopoietin 2, also known as Ang-2) with a correlation coefficient (r) of 0.7133 (p value = 3.95E−89) (Fig. 3a), suggesting that a tightly co-regulated mechanism exists between ESM1 and ANGPT2. ANGPT2 was also up-regulated in HNSCC (Fig. 3b, Table 2).