According to the data provided by 3 included studies [16, 19, 20], we explored the association of PIK3CA gene expression with sex (male vs. female), age (≥65 vs. <65), differentiation (lower vs. higher), lymph node metastasis (+ vs. -), TNM stage (advanced vs. limited), and smoking history (yes vs. no). Here, PIK3CA is linked to metastatic malignant neoplasm in the lymph nodes.