Further exploration showed that the expression of piR-63049 (also known as piR-hsa-174699 for human) was also significantly up-regulated in plasma of OVX rats (Figure 2C), and in the bone tissues (Figure 2D) and plasma (Figure 2E) of postmenopausal osteoporotic patients, suggesting that the expression of piR-63049 may be associated with postmenopausal osteoporosis. This evidence concerns the gene PIR and postmenopausal osteoporosis.