Compared to low-grade subtype lung adenocarcinoma, patients with high-grade subtype lung adenocarcinoma were more likely to be younger (p < 0.001), had abnormal preoperative serum CEA level (p = 0.070), had lymphovascular invasion (p = 0.007), had poor differentiation (p = 0.001), had positive spread through air spaces (p = 0.001), had larger tumor size (p < 0.001), had more lymph node metastasis (p = 0.047), and had higher tumor–node–metastasis (TNM) stage (p = 0.030). This evidence concerns the gene CEACAM5 and neoplasm.