CCS and renal cell carcinoma: Based on a literature survey that revealed detectable levels of sPD-1 and sPD-L1 in specimens of cancer patients with different types of cancer [48,49,50,51,52], in our study, we evaluated cPD-1 and cPD-L1 in pediatric patient specimens diagnosed with WT, hypernephroma, and CCS by flow cytometry.