LAUSR

OBJECTIVE To characterize the relationship between metastasis-associated protein 1 (MTA1) and spread through air spaces (STAS), and to investigate the joint prognostic value of MTA1 and STAS in resected lung adenocarcinomas. METHODS We retrospectively reviewed 208 operated patients with stage I-III lung adenocarcinoma from January 2009 to December 2014. STAS was identified by H&E staining. Expression level of MTA1 was determined by immunohistochemistry. The relationship between MTA1 and STAS was determined by using a logistic regression model. The synergistic effects of MTA1 and STAS on prognosis were analyzed using a Cox proportional hazards regression model. RESULTS Patients with either STAS or high expression of MTA1 had significantly worse overall survival (OS) and shorter recurrence-free survival (RFS) than those without STAS or with low expression of MTA1 (p < 0.001). Among 107 patients with STAS presence in lung adenocarcinomas, 57 (53.3%) cases had high expression of MTA1. High expression of MTA1 was positively associated with the increased frequency of STAS presence (p < 0.01). Subgroup analysis showed that the patients with both high expression of MTA1 and STAS-positive presence had significantly worst OS and shortest RFS compared with the others (p < 0.001), while the patients with high expression of MTA1 /STAS-negative presence shared similar RFS with those with high expression of MTA1 /STAS-positive presence. Furthermore, high MTA1 levels in STAS-positive patients was associated with a higher risk of postoperative metastasis and recurrence (p < 0.001). CONCLUSIONS STAS was more frequently observed in adenocarcinomas with high MTA1 expression levels. MTA1 was associated with a higher risk of worse overall survival among patients with STAS and could provide helpful prognostic information in STAS-positive patients with stage I-III lung adenocarcinoma.