MKI67 and neoplasm: In analyzing viable tumor burden (25), Ki67 staining showed that tumors from mHMTA consisted of only a thin outer shell of live/proliferating cells surrounding a necrotic center (Fig. 4D), whereas those from mHM had a depth of viable tissue that was more than twofold thicker (P = 0.048, two-group t test; Fig. 4E).