MiR21 has been found to be overexpressed in CCA, conferring a variety of oncogenic effects, including inhibition of programmed cell death 4 (PDCD4) and tissue inhibitor of matrix metalloproteinase 3 (MMP3), along with activation of phosphoinositide 3-kinase (PI3K) signaling [10]. The gene discussed is PDCD4; the disease is cholangiocarcinoma.