Recent advances in diagnostic and therapeutic approaches for pulmonary enteric adenocarcinoma

Pulmonary enteric adenocarcinoma (PEAC), also known as adenocarcinoma-enteric type of the lung, is a rare variant of non-small cell lung cancer (NSCLC) that shows similar morphological and immunohistochemical (IHC) features to colorectal adenocarcinoma and necessitates gastroenteroscopy to exclude enteric-origin lesions. Moreover, IHC diagnostic criteria for PEAC are more explicitly defined in the 2015 World Health Organization (WHO) Classification of Lung Tumors. When the percentage of tumor cells with enteric differentiation exceeds > 50% of tumor tissue, then at least one enteric differentiation marker [cytokeratin 20 (CK20), tail homologous box (CDX2), mucin 2 (MUC2), and specific AT-sequence binding protein 2 (SATB2)] is detected. This PEAC, an uncommon solid tumor in lung cancer, is characterized by a poor prognosis, pathological and molecular traits, and a unique clinical response in imaging. However, their molecular features and therapeutic biomarkers are still unexplored, and their diagnosis and treatment remain difficult. Thus, systematic review and combined analysis data were obtained from previously published literature.