Mitoses-specific antibodies, MPM-2 and Phospho-Histone H3

MPM-2 is a monoclonal antibody raised against HeLa cells which recognises mitosis-specific phosphoproteins topoisomerase II alpha, microtubule associated protein, NimA and two Cdc2- inhibitory kinases. These proteins share epitopes that are phosphorylated during the induction of mitosis.

Immunohistochemical expression

MPM-2 stains the cytoplasm from early prophase through metaphase, anaphase and telophase¹. There is weak nuclear staining in interphase¹. Nerve fibres and macrophages show non-specific cytoplasmic staining¹.

Both MPM-2 and PHH3 result in higher mitotic counts than are obtained with H/E sections. In one study across a range of tumours, the average mitotic counts per 10 HPF were 5.9 ± 15.8, 11.0 ± 27.3 and 10.1 ± 22.6 for H/E, MPM-2 and PHH3 staining respectively³. Staining may be unsatisfactory in large specimens, such as breast lumpectomies and mastectomies, due to delayed fixation¹: it may be less affected than is staining for PHH3.

Diagnostic utility

Counting mitoses

References

¹ Tapia C, Kutzner H, Mentzel T, et al. Two Mitosis-Specific Antibodies, MPM-2 and Phospho-Histone H3 (Ser28), Allow Rapid and Precise Determination of Mitotic Activity. Am J Surg Pathol 2006; 30:83-89

This page last revised 21.1.2006.

©SMUHT/PW Bishop