ABCG2 and osteosarcoma: Other studies focused on osteosarcoma have revealed that overexpression of CD44v6 (171, 172), CD133 (173), CD133/CD44 combination (174), CDH11 (172), β-catenin (172), GAPLINC (145), CD44-miR-199a-3p axis (144) and the combination CD44/IGF1R/ABCG2 (175) could provide valuable information as prognostic markers in this sarcoma.