Abstract KRAS G12C-mutated non-small cell lung carcinoma (NSCLC), caused by a glycine-to-cysteine substitution at codon 12, is associated with poor prognosis and is now targetable with specific inhibitors. We retrospectively analyzed 279 KRAS G12C-mutated NSCLC cases (2017–2023) from our registry with available histologic, immunohistochemical, and molecular data. The cohort included 279 patients (125 females, 151 males; mean age 67 years, range 29–91). Most tumors were primary lung carcinomas (n = 229, 82%), while 45 (16%) were metastatic at presentation. Morphologic evaluation was available in 240 tumors: 37% showed solid squamous cell carcinoma (SCC)-like features, 61% rhabdoid/plasmacytoid morphology, and 17% sarcomatoid features. Adenocarcinoma-associated patterns were present in 67 cases, often mixed, and focal solid growth occurred in 77%. TTF1, Napsin A, and CK7 were positive in 86%, 87%, and 98%, respectively, whereas squamous markers were infrequent (p40/p63 7%, CK5/6 8%). PD-L1 expression was detected in 65%. Co-mutations most commonly involved TP53 (n = 27) and STK11 (n = 12); IDH1 / 2, PIK3CA , and CTNNB1 mutations occurred in four cases each, MET in two cases, and BRAF , FGFR2 , FGFR3 , and GNAS in one case each. Two gene fusions were identified ( LRP12 :: NRG1 , FGFR3 :: TACC3 ). Mean survival was 1.89 years, with one- and five-year survival rates of 54% and 25%. KRAS G12C-mutated NSCLC is clinically aggressive and frequently shows solid growth with rhabdoid, plasmacytoid, or SCC-like morphology, which may lead to misclassification and missed genetic testing. Immunohistochemistry and molecular profiling are essential for accurate classification and enabling targeted therapy.
Bradová et al. (Wed,) studied this question.