MKI67 and neoplasm: Certain approaches employed both aforementioned methods: Marchetti et al. (1996) determined the number of ki-67-positive cells per 2000 tumor cells and also noted the specific staining pattern (diffuse/localized), subgrouping the latter into two distinct clusters (cut-off values: 0.2%–6% positivity / 7–9% positivity) [52].