Through the analysis of the circRNA expression features in lung cancer and adjacent normal tissues using qPCR, Yao et al. showed that circRNA_100876, encoded by RNF121 (ring finger protein 121) gene, is significantly upregulated in lung cancer samples, and Kaplan-Meier survival analysis revealed that patients with high expression levels of circRNA_100876 showed shorter overall survival times [50]. Here, RNF121 is linked to lung cancer.