They confirmed for the first time an inverse correlation between miR-21 and Pdcd4 protein expression and proposed that miR-21 has a crucial role in post-transcriptional down-regulation of tumor suppressor Pdcd4, whose function is to stimulate cancer cell invasion, intravasation, and metastasis (Asangani et al., 2008). The gene discussed is PDCD4; the disease is neoplasm.