CD4 and neoplasm: We calculated the linear correlation between levels of expression of select markers isolated from different tumors from the same patient and found that expression of CD86 on APCs (r = 0.989; p = 0.011), PD-L1 on APCs (r = 1; p = 0.00049) (Fig. 6A), and the proportion of PD-1high CD4+ T cells (r = 0.953; p = 0.012) (Fig. 6B) all exhibited strong positive correlations between tumor sites.