PTGDR and osteosarcoma: LncRNAs often serve as ceRNAs of Rac1 and promote its expression to promote proliferation and metastasis in various types of cancer, such as MALAT1 binding to miR-509 in osteosarcoma cells [161], the lncRNA TP73-AS1 (TP73 antisense RNA 1) to miR-142 in osteosarcoma cells [162], the lncRNA UCA1 (urothelial cancer associated 1) to miR-126 in myelogenous leukemia cells [163], the lncRNA FTH1P3 (ferritin heavy chain 1 pseudogene 3) to miR-224-5p in uveal melanoma cells [164], and XIST to miR-137 in glioma cells [165].