CD4 and neoplasm: From this finding, we hypothesize that accumulation of tumor-reactive clones in the tumor is explained by two independent processes: “expansion in dLN” and “tumor in situ expansion.” Interestingly, anti-CD4 mAb treatment mainly increased the proportion of “dLNmajor” clones, which is consistent with our previous observation that anti-CD4 mAb treatment promotes the cell-cycle progression of CD44hi CD8+ T cells in the dLN but not in the tumor (7).