Prognostic Impact of Reactive Oxygen Species Modulator 1 in Surgically Resected Epidermal Growth Factor Receptor-Mutant Lung Adenocarcinomas

Abstract

<b><i>Introduction:</i></b> Reactive oxygen species modulator 1 (Romo1) is a novel protein that is critically involved in the intracellular production of reactive oxygen species. Evidence has revealed that Romo1 is associated with treatment outcomes of various human malignancies, including lung cancer. However, the clinical implications of this protein in surgically resected lung cancers harboring epidermal growth factor receptor (EGFR) mutations have not been investigated. <b><i>Methods:</i></b> Data were collected from patients who underwent curative resection of EGFR-mutant lung adenocarcinoma. Romo1 protein expression levels were measured in the tumor tissue using immunohistochemical staining and evaluated semi-quantitatively using the histochemical score. Univariate and multivariate analyses were performed to identify the clinicopathological parameters that may be associated with clinical outcomes. <b><i>Results:</i></b> A total of 98 samples were analyzed. Using the cutoff H score of 200, the population was classified into low (<i>n</i> = 73) and high (<i>n</i> = 25) Romo1 groups. Romo1 expression was significantly higher in smokers, patients with stage III disease, and patients who experienced recurrence after surgery (all <i>p</i> &lt; 0.05). Multivariate analyses showed that advanced-stage and poorly differentiated cancers were associated with shorter disease-free survival (DFS). In addition, high Romo1 expression was independently associated with poor DFS (hazard ratio = 2.18, 95% confidence interval: 1.10–4.32, <i>p</i> = 0.0261). <b><i>Conclusions:</i></b> Our data showed that Romo1 overexpression was significantly associated with early recurrence in patients with resected EGFR-mutant lung adenocarcinoma. Although large-scale studies are required, Romo1 may play a prognostic role in this patient population.