Phospho-Histone H3 (pHH3) is a recently
described immunomarker specific for cells undergoing mitosis. The
phosphorylation of histone H3 plays an important role in gene expression,
chromatin remodeling, chromosome condensation and cell division. Histone H3
phosphorylation may initiate at different phases of cell division in different
organisms, but metaphase chromosomes are always found to be heavily
phosphorylated. H3 phosphorylation at serine 10 and serine 28 is coupled with
mitotic chromosome segregation and condensation. Prognostic significance of the
mitotic index (MI) using the Mitosis marker anti-PHH3 antibody have been
reported to be of great value in breast cancer, melanoma and meningiomas. pHH3
staining may also be a useful method in which accurate determination of
proliferation potential is relevant to tumor grading or clinical treatment
decision-making.