Major driver mutations of pulmonary adenocarcinomas have been identified and highlighted as actionable targets for precision cancer medicine. As phenotype is largely determined by genotype, genetic changes associated with morphologic features have recently received more attention from both pathologists and clinicians. The morphologic features of adenocarcinomas with mutations in EGFR or KRAS, or translocated ALK, have rarely been described. Pulmonary adenocarcinomas with EGFR mutations, the most common driver mutation encountered in Asian patients with pulmonary adenocarcinoma, show lepidic or papillary organotypic growth patterns. KRAS-mutated adenocarcinomas demonstrate nonorganotypic growth patterns, especially mucin-containing cells. P53 mutations are associated with aggressiveness rather than growth patterns. HER2 mutations are observed in mucinous adenocarcinoma and adenocarcinoma with micropapillary features. The histologic features of BRAF-mutated adenocarcinomas have not yet been established, but papillary, lepidic, solid, and acinar patterns have been observed. Adenocarcinomas with rearrangement of ALK, ROS1, and RET genes share similar histologic features, such as solid signet-ring cells and cribriform formation. However, adenocarcinomas with NRG1 rearrangements frequently show mucinous morphology. The histologic features and related mutations of adenocarcinomas with expression of programmed cell death-1 and programmed cell death ligands-1 may be helpful in guiding immunotherapeutic treatment. This review describes histopathologic features of adenocarcinomas and their correlation with molecular alterations.
Departments of *Pathology
†Oncology and Pulmonology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea
‡Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Weill Medical College of Cornell University, Houston, TX
Supported by the Leading Foreign Research Institute Recruitment Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science, and Technology (MEST) (2011-0030105).
The authors have no funding or conflicts of interest to disclose.
Reprints: Jae Y. Ro, MD, PhD, Department of Pathology and Genomic Medicine, Houston Methodist Hospital, Weill Medical College of Cornell University, 6565 Fannin Street, Houston 77030, TX (e-mail: email@example.com) and Se Jin Jang, MD,PhD, 88 Olympic-ro 43 gil, Songpa-gu 05505, Seoul, Korea (firstname.lastname@example.org).
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