MiR-21 suppressed the action of various apoptotic and tumor suppressor genes including phosphatase and tensin homolog (PTEN), programmed cell death 4 (PDCD4), and tropomyosin 1 (TPM1) leading to an induction of cancer cell proliferation, and migration, as well as inhibiting apoptosis [6,7]. The gene discussed is TPM1; the disease is cancer.