As shown in Fig. 1C, the average numbers of CD4-and CD8-positive T cells were significantly increased in the tumor stroma, compared with those in the tumor parenchyma (tumor stroma versus tumor parenchyma: CD4, 22±3.6 versus 7.4±0.9; CD8, 32.8±4.2 versus 16±2.5; both P<0.01). Here, CD4 is linked to neoplasm.