We engineered MCC cell lines to express doxycycline‐inducible shRNAs targeting LSD1 (shLSD1.1 or shLSD1.2), Renilla luciferase (shRenilla, negative control), or the essential ribosomal protein RPS15 (shRPS15, positive control) and added doxycycline (Fig EV1B). Here, KDM1A is linked to Merkel cell skin cancer.