Prognostic impact of microscopic vessel invasion and visceral pleural invasion and their correlations with epithelial-mesenchymal transition, cancer stemness, and treatment failure in lung adenocarcinoma.

Objectives: Microscopic vessel invasion (MVI) and visceral pleural invasion (VPI) have been recently reported as poor prognostic factors of non-small cell lung cancer. Epithelial-mesenchymal transition (EMT) and cancer stemness (CS) are known malignant phenotypes that induce resistance to cancer therapy. We aimed to assess the prognostic significance of MVI and the correlations among VPI/MVI, EMT, CS, and treatment failure for recurrent tumor.

Materials And Methods: From 2002 to 2013, 1034 consecutive patients with pathological T1-4N0-2M0 lung adenocarcinoma underwent complete resection. Moreover, we established 206 tissue microarray (TMA) samples from 2002 to 2007. We then evaluated the prognostic impact of MVI, including conventional clinicopathological factors, and analyzed the VPI/MVI, EMT, CS, and treatment failure by TMA immunohistochemical staining.

Results: Among the 1034 cases, the proportion of patients with a 5-year overall survival (OS) period was 63.9% and 88.2% (MVI: +/-; p < .001). Multivariate analysis revealed that both MVI and VPI were independent predictors of OS (HR 1.57 and 1.47, respectively). Significant separation of the OS rate curves was observed among the 3 groups [VPI/MVI: both positive (2), either positive (1), and both negative (0)]. Among the 206 TMA cases, these 3 groups of VPI/MVI were significantly correlated with EMT and CS. The median time to progression after recurrence were 3.8, 8.9, and 15.9 months, respectively (VPI/MVI: 2/1/0; p =  0.016).

Conclusion: MVI and VPI are significant prognostic factors of lung cancer, and they are correlated with EMT, CS, and treatment failure for recurrent tumor.