CD274 and neoplasm: Secondly, the database had insufficient information about high-risk lifestyle factors (e.g., large consumption of alcohol, eat high-temperature food or pickled food), tumor markers, imaging examination, important molecular factors (PD-1/PD-L1 gene status), metastasis sites, etc. They are believed as important factors for predicting LNM, DM, and prognosis of T1-2 ESCA which should be further explored.