Wan Z, et al. - In this retrospective case-control study, researchers evaluated serum levels of soluble death receptor 5 (sDR5) in small-cell lung cancer (SCLC) patients vs those in healthy controls. In 50 healthy controls and 82 SCLC patients before and after first-line chemotherapy, the sDR5 levels were analyzed using ELISA. Cox proportional hazard analysis showed that serum sDR5, Veterans Administration Lung Study Group stage, and PS status post-treatment levels were all independent predictors for overall survival of patients. Investigators observed that the serum soluble DR5 level was upregulated in SCLC patients compared with that of the healthy controls. The findings of the present research show that to predict treatment responses and survival of SCLC patients, the serum concentration of sDR5 could be further confirmed as a biomarker.