The proportion of CD4+ T-cells expressing PD-1 was generally lower compared to CD8+ T-cells but still significantly elevated in the tumor and ascites (40.6% of tumor-derived and 19.3% of ascites-derived CD4+ T-cells) compared to healthy individuals and patient blood (0.7% and 4.6%, respectively) (Figures 1(a) and 1(b)). Here, CD4 is linked to neoplasm.