As shown in Fig. 3, in the CH and C background groups, CD8 expression levels in the peritumor parenchymas were significantly higher than those in the paired tumor parenchymas (peritumor parenchyma vs. tumor parenchyma: CH background, 18.4±1.4 vs. 15.0±3.3; C background, 19.8±2.2 vs. 12.9±4.1; both P<0.01). This evidence concerns the gene CD8A and cyclic hematopoiesis.