Engineered destabilized 3’UTR of ERBB2 degrades ERBB2 in ERBB2-expressing EGFR T790M lung cancer cells, ERBB2+ trastuzumab-resistant breast cancer cells, in wildtype ERBB2+ breast cancer cells, in ERBB2-mutated lung cancer cells, and in ERBB2-expressing colorectal cancer cells. The gene discussed is ERBB2; the disease is breast cancer.