Four studies described the staining method, of which 2 used hematoxylin and eosin,113,164 1 employed toluidine blue,128 and 1 utilized anti-Proliferating Cell Nuclear Antigen (PCNA) immunolabeled slides.138 The proportion of mitotic figures was calculated among various numbers of tumor cells: 500,113 1000 (in PCNA hotspot138 or peripheral areas98), at least 10,000,164 and all cells within 10 hotspot high-power fields (at 25× magnification).128 Two studies created photomicrographs for counting,128,164 with 1 also using software for cell number estimation.128. Here, PCNA is linked to neoplasm.