SOX2 and metastatic malignant neoplasm in the lymph nodes: No relationship was observed between SOX2 expression and tumor size (two studies with 347 cases, ≥5 vs. ≤5 cm: OR = 0.78, P=0.759), pT-stage (four studies with 526 cases, pT-stages 3-4 vs. 1-2: OR = 1.12, P=0.778), lymph node metastasis (three studies with 225 cases, yes vs. no: OR = 3.19, P=0.1), and distal metastasis (three studies with 438 cases, yes vs. no: OR = 1.26, P=0.694) (Figure 3).