ALKBH5 and esophageal squamous cell carcinoma: Although no association was identified between ALKBH5 expression and age (P = 0.524) and sex (P = 1.000) using 206 ESCC samples (Table 2), ALKBH5 expression was inversely correlated with tumor size (T classification; P = 0.006), lymph node invasion (N classification, P = 0.019), clinical stage (I–II versus III–IV, P = 0.027), and histological grade (P = 0.023) in these patients (Figure 1E, 1F and Table 2).