Increasing reports have identified various downstream genes of miR-320a including programmed cell death protein 1 (PD1) in malignant mesothelioma [37], interleukin 4 in preeclampsia [38], microtubule-associated protein 9 (MAP9) in postmenopausal osteoporosis [39], and Rab protein 14 (RAB14) in gastric cancer [40]. The gene discussed is PDCD1; the disease is postmenopausal osteoporosis.