In the 80 cases of classic LCLC, the positive expression rates of 34βE12, CK5/6 and P63 were 100, 76.3 and 52.5%, respectively; the positive expression rates of CK7 and TTF-1 were 100 and 51.3%, respectively; however, positive expression of Syn and CgA was not observed. This evidence concerns the gene KRT5 and lung large cell carcinoma.