Figure 1. Circulating immune cell subsets in patients with prostate cancer or non-small cell lung cancer before and during the course of chemotherapy. (A–C) Patients (n = 15) with hormone refractory metastatic prostate cancer were treated with docetaxel and evaluated before and during therapy for the number of peripheral blood mononuclear cells (PBMCs) (A), the frequency of CD4⁺ T cells among PBMCs (B), and the frequency of regulatory T cells (Tregs) among CD4⁺ T cells (C). Peripheral blood samples were collected at the indicated time points. Statistical analyses were performed using Friedman and Dunn’s multiple comparison tests and revealed a significant decrease in the frequency of Tregs at post-cycle I (**P < 0.01) and pre-cycle II (***P < 0.001). (D–F) Patients (n = 14) with stage IB, II, and IIIA non-small cell lung cancer (NSCLC) were evaluated before and during therapy with cisplatin plus vinorelbine for the number of PBMCs (D), the frequency of CD4⁺ T cells among PBMCs (E), and the frequency of Tregs among CD4⁺ T cells (F). Peripheral blood samples were collected at the indicated time points. Statistical analyses were performed using Friedman and Dunn’s multiple comparison tests; * P < 0.05, *** P < 0.001. In all dot plots, the median and interquartile range are shown.