Elevated serum levels of human relaxin-2 in patients with esophageal squamous cell carcinoma

Figure 1 Survival of patients with esophageal squamous cell carcinoma in relation to their serum human relaxin 2 levels. The cutoff value of serum human relaxin 2 (H2 RLN) concentration for dividing patients into groups A and B was defined as 0. 462 ng/mL which represents the mean plus 1 SD measured from the healthy control subjects. Survival analysis between group A (H2 RLN, ≥ 0.462 ng/mL) and group B (H2 RLN, < 0.462 ng/mL) was assessed using the Kaplan-Meier method, and the survival difference between the groups was compared using the log rank test (P = 0.018).

Figure 2 Comparison of overall survival between different disease stages. We also analyzed the prognostic value of human relaxin 2 (H2 RLN) levels in selected patient subgroups stratified according to disease stage. Esophageal squamous cell carcinoma patients with elevated H2 RLN levels had a significantly shorter overall survival rate compared to patients with non-elevated H2 RLN levels in the clinical stage I-II subgroup (n = 54; log-rank P < 0.001; Figure 3A), and the clinical stage III-IV subgroup (n = 87; log-rank P < 0.001; Figure 3B).

Figure 3 Overall survival curves for patients with esophageal squamous cell carcinoma after curative resection. The patients were categorized with elevated (≥ 0.462 ng/mL) or non-elevated (< 0.462 ng/mL) levels of relaxin. P values were determined using the log rank test. A: Clinical stage I-II subgroup; B: Clinical stage III-IV subgroup.