A lentivirus expressing an HRAS-targeting guide RNA, GAL4, and UAS-activated Cas9 nuclease (HRAS-LV) induced the silencing of HRAS in bladder cancer cell lines (<50% expression level observed following treatment with negative control lentivirus (NC-LV)), whereas the HRAS was unaffected in human foreskin fibroblasts, illustrating the cancer-specific silencing of HRAS by the human TERT promoter-driven CRISPR/Cas9 genetic circuit. The gene discussed is TERT; the disease is cancer.