The Utility of Phosphohistone H3 in Breast Cancer Grading

Abstract

The commonly used Nottingham Grading System in breast cancer takes into consideration the presence of tubular formation, nuclear pleomorphism, and the mitotic index (MI), among which the latter has been shown to be the most powerful prognostic factor. In practice, histologic grading is highly subjective, with only moderate interobserver reproducibility. Phosphorylation of histone H3 has been demonstrated to be a specific event in the mitotic phase, and is negligible during interphase. In this study, we evaluated the efficacy of Phosphohistone H3 (PHH3) in the breast cancer grading of 97 consecutive biopsy specimens. PHH3 antibodies clearly revealed discrete, strong nuclear immunoreactivity in mitotically active cells even under low magnification. The PHH3 MI showed a significant correlation with that derived by hematoxylin and eosin (H&E) staining as well as the Ki-67 proliferation index. Further, the pairwise κ-value of the MI was significantly increased, and the pairwise agreement was also markedly improved by PHH3 immunostaining, although a significant proportion of breast cancer cases were upgraded by use of the PHH3 MI. Our data showed that PHH3 provided a more sensitive and accurate MI with less interobserver variability when compared with conventional H&E staining, thus emphasizing its potentially increased value in practice. Reconsideration of breast cancer grading with integration of PHH3 should be considered if it continues to demonstrate superiorly to traditional H&E staining.

The mitosis‐specific marker phosphohistone‐H3 (PHH3) is an independent prognosticator in uterine smooth muscle tumours: an outcome‐based study

“…Regarding the performances of PHH3 and H&E staining, our results are consistent with those of others . PHH3 staining enhances the identification of mitoses, providing more efficient, more sensitive and more specific assessment, with little background staining .…”

“…There was excellent interobserver agreement among three pathologists in our study. Although PHH3 scores are generally higher than traditional mitosis counts obtained with H&E, the two methods still show a similar trend, with a moderate positive correlation . PHH3 scores were significantly higher than H&E mitotic counts only in clinically malignant tumours (group 2 tumours), and not in benign USMTs with atypical histology (group 1 tumours).…”

Digital image analysis of Ki67 in hot spots is superior to both manual Ki67 and mitotic counts in breast cancer

“…In contrast to these findings, the software tested for automatic assessment of PHH3 cannot be recommended for either surrogate subtyping, transcriptomic grade classification or prognostication at this stage. Thus, the findings of previous studies by Cui et al ., in which manual assessments of PHH3 were shown to increase the interobserver concordance of mitotic indexes, and by Gerring et al ., in which PHH3 had a greater prognostic value than Ki67 when manually scored in tissue microarrays, could not be repeated with the VIS software. A challenge for DIA of this biomarker might be the low intensity of the true positive signal relative to staining artefacts, coal markings, natural pigments, lipofuscin, haemosiderin, and other visual noise.…”

Ki-67 proliferation index but not mitotic thresholds integrates the molecular prognostic stratification of lower grade gliomas

“…The great value of PHH3 has already been demonstrated in several human tumors in which mitotic count is crucial for diagnostic and/or prognostic purposes (i.e. melanoma [11], breast cancer [12], gastrointestinal stromal tumor [13], adrenocortical carcinoma [14] and meningioma [15]). In LGG, two previous reports confirmed the diagnostic usefulness of PHH3 [9, 16], although they did not investigate the concordance among pathologists.…”