Seven-lncRNA signature in esophageal squamous cell carcinoma

A seven-lncRNA signature was identified in the training set, which is significantly associated with overall survival (OS) (Hazard Ratio [HR]: 3.535, 95% confidence interval [CI]: 2.113-5.915, P < 0.001) and disease-free survival (DFS) (Hazard Ratio [HR]: 2.413, 95% confidence interval [CI]: 1.573-3.703, P < 0.001). Patients in high-risk group have shorter overall survival (HR: 3.555, 95% CI: 2.195-5.757, p < 0.001) and disease-free survival (HR: 2.537, 95% CI: 1.646-3.909, p < 0.001) in the training set, and we found the same conclusion in the independent set for OS (HR 2.665, p < 0.001) and DFS (HR 2.360, p = 0.001). Combination of the signature and TNM staging system was more powerful than TNM staging system alone in predicting outcomes in both the training set (AUC: 0.772 vs 0.681, p = 0.002) and in the independent set (AUC: 0.772 vs 0.660, p = 0.003). Using a 2520 probe microarray, we retrospectively analyzed lncRNA expression profiles in 141 samples of ESCC and 81 paired non-cancer specimens from SUN YAT-SEN University Cancer Center (Guangzhou, China), which were served as the training set to identify a signature associated with clinical outcomes. We randomly selected 40 paired tumor tissues and paired adjacent normal tissues from the above samples for the quantitative RT-PCR to confirm the credibility of microarray data. Then we conducted the quantitative RT-PCR in another 103 samples of ESCC as an independent set to verify the signature.