PIK3CA and osteosarcoma: There are also many microRNAs whose effects on the PI3K/AKT pathway are directly on PI3K and AKT molecules, for example, miR-340-5p is under-expressed in osteosarcoma as an oncogenic factor, and thus as a direct target gene of miR-340-5p, PI3K receives significantly less direct inhibition, leading to abnormal PI3K/AKT pathway and a OS development with a significant contribution (208).