[Clinicopathologic features and genetic profile of the redefined large cell lung carcinoma]

Objective: To investigate the clinicopathologic features and genetic profile of large cell lung carcinoma (LCC) redefined by new classification. Methods: Basing on 2015 WHO classification criteria in redefining large cell lung carcinoma, the expression of specific markers (TTF1, Napsin A, p40, CK5/6, CK, vimentin and ZEB1) was detected by immunohistochemistry and D-PAS staining in 303 surgically-removed lung specimens previously diagnosed as large cell lung carcinoma. The clinicopathologic and genetic characteristics (including EGFR, KRAS, BRAF, ALK and ROS1 gene mutation) were analyzed. Results: Based on the new definition of LCC, 116 cases (116/303, 38.3%) of LCC formerly diagnosed were reclassified as solid adenocarcinoma, 49 cases (49/303, 16.2%) as squamous cell carcinoma, 6 cases (6/303, 2.0%) as adenosquamous carcinoma, 22 cases (22/303, 7.3%) as spindle cell carcinoma and only 110 cases (110/303, 36.3%) as large cell carcinoma. Redefined LCCs were characterized as middle-age (range 40-80), male (102/110, 92.7%) and smoking patients (64/110, 58.2%) with intermediate-advanced stage. Among 110 cases, 9 cases with EGFR mutation and 10 cases with KRAS mutation and 1 case with ALK fusion were found. No BRAF and ROS1 alterations were identified. Conclusions: According to the new classification, LCCs formerly diagnosed are mostly reclassified as adenocarcinoma and non-keratinizing squamous cell carcinoma. The newly defined LCC may significantly benefit from clinical therapy.