PPT1 and clear cell renal carcinoma: Their marker genes included PPT1 and KPNA2. PPT1 was reported as a molecular target of chloroquine derivates in melanoma cell lines, closely correlating with the poor prognosis in several cancers, such as breast cancer, clear cell renal cell carcinoma, head and neck squamous carcinoma, thyroid cancer, and colon adenocarcinoma.43–45KPNA2, a nucleocytoplasmic transporter known to be involved in many cellular processes including differentiation, development, and immune response46 was also revealed to have the potential act as a stemness marker in LUSC.