However, the increased proliferation (determined by 5–20% cells showing Ki-67 positive staining; Figure 6A, 6B) [1, 2] and augmented mitotic index (monitored by positive phosphorylated histone H3 staining; Figure 6C, 6D) [26], indicated that the percentage of the intermediate grade carcinoid tumor, AC, is significantly higher in TKO mice (Figure 6E). Here, MKI67 is linked to carcinoid tumor.