Introduction: Reactive oxygen species modulator 1 (Romo1) is a novel protein that is critically involved in intracellular production of reactive oxygen species. Evidence revealed that Romo1 is related with treatment outcomes of various human malignancies including lung cancer. However, clinical implication of this protein in surgically-resected lung cancer harboring the epidermal growth factor receptor (EGFR) mutation has not been investigated.
Methods: Data were collected from the patients who underwent curative resection for EGFR-mutant lung adenocarcinoma. Romo1 protein expression level was measured in the resected tumor tissue using immunohitochemical staining and evaluated semiquantatively using histochemical score (H score). Univariate and multivariate analyses were performed to identify clinicopathological parameters that may be associated with clinical outcomes.
Results: A total of 98 samples were analyzed. Using the cutoff H score 150, the population was classified into low (n=73) and high (n=25) Romo1 groups. Romo1 expression was significantly higher in smokers, patients with stage III disease, and patient who experienced recurrence after surgery (all p<0.05). In the multivariate analyses, advanced stage and poorly differentiated cancer were associated with shorter disease-free survival (DFS). In addition, high Romo1 expression was independently associated with poor DFS (hazard ratio [HR] = 2.20, 95% confidence interval [CI]:1.10–5.42, p = 0.0324).
Conclusions: Our data showed that Romo1 overexpression was significantly associated with early recurrence in patients with resected, EGFR-mutant lung adenocarcinoma. Although large-scaled data are needed, Romo1 may have prognostic role for this patient population.