SMARCA2 deficiency in NSCLC: a clinicopathologic and immunohistochemical analysis of a large series from a single institution

Background: SMARCA2 (SWI/SNF Related, Matrix Associated, Actin Dependent Regulator of Chromatin, Subfamily A, Member 2) is an important ATPase catalytic subunit in the switch-sucrose nonfermenting (SWI/SNF) complex. However, its relationship with the pathological features of NSCLC and its prognosis remain unclear. Methods: We retrospectively reviewed 2390 patients with surgically resected NSCLC, constructed tissue microarrays (TMAs) and performed immunohistochemical assays. We analyzed the correlation of SAMRCA2 with clinicopathological features and evaluated its prognostic value. Results: Among 2390 NSCLC cases, the negative expression ratios of SAMRCA2, SMARCA4, ARID1A, ARID1B and INI1 were 9.3%, 1.8%, 1.2%, 0.4% and 0%, respectively. In NSCLC, male sex, T3 and T4 stage, moderate and poor differentiation, tumor >= 2 cm, Ki67 >= 15%, SOX-2 negative expression, middle lobe lesion and adenocarcinoma were relative risk factors affecting SMARCA2-negative expression. In lung adenocarcinomas, high-grade nuclei, histological morphology of acinar and papillary, solid and micropapillary and TTF-1-negative expression were relative risk factors affecting SMARCA2-negative expression. Kaplan-Meier survival analysis showed that the OS was shorter in the SMARCA2-negative group. Multivariate survival analysis revealed that SMARCA2-negative expression was an independent factor correlated with a poor prognosis in NSCLC. Conclusion: In conclusion, SMARCA2-negative expression is an independent predictor of a poor outcome of NSCLC and is a potential target for NSCLC treatment.