LAPTM4B and cancer: As most cancer cells undergo genome instability and gene amplification [27], we examined the copy number variation (CNV) in the CCLE database and found OS cell lines do not display increased LAPTM4B copy numbers (Fig. 4a), which was supported by the data that LAPTM4B CNV doesn’t display any significant shift in collected OS tumor samples compared with normal control tissues (Fig. 4b).