Among the 10 included studies which focused on PIK3CA mutation in NSCLC, more than half of them did not provide detailed information for us to calculate the relation of PIK3CA gene mutation with sex, age, lymph node metastasis, TNM stage, and smoking [21, 22, 25–28]. The gene discussed is PIK3CA; the disease is metastatic malignant neoplasm in the lymph nodes.