CTLA4 and melanoma: To confirm the predictive value of CTC1-STN1, we curated three datasets of expression data for melanoma patients treated with anti-PD-1, anti-PD-L1, or anti-CTLA4 and one dataset of expression data for metastatic urothelial cancer patients treated with anti-PD-L1 (Hugo et al., 2016; Riaz et al., 2017; Lauss et al., 2017; Mariathasan et al., 2018).