Assessment and Prognostic Significance of Mitotic Index Using the Mitosis Marker Phospho-histone H3 in Low and Intermediate-grade Infiltrating Astrocytomas

Abstract

Distinguishing between grade II and grade III diffuse astrocytomas is important both for prognosis and for treatment decision-making. However, current methods for distinguishing between grades based on proliferative potential are suboptimal, making identification of clear cutoffs difficult. In this study, we compared the results from immunohistochemical staining for phospho-histone H3 (pHH3), a specific marker of cells undergoing mitosis, with standard mitotic counts (number of mitoses/10 high-power fields) and MIB-1 labeling index values for assessing proliferative activity. We tested the relationship between pHH3 staining and tumor grade and prognosis in a retrospective series of grade II and III infiltrating astrocytomas from a single institution. The pHH3 index (per 1000 cells), MIB-1 index (per 1000 cells), and number of mitoses per 10 high-power fields were determined for each of 103 cases of grade II and III diffuse astrocytomas from patients with clinical follow-up. pHH3 staining was found to be a simple and reliable method for identifying mitotic figures, allowing a true mitotic index to be determined. The pHH3 mitotic index was significantly associated both with the standard mitotic count and with the MIB-1 index. Univariate analyses revealed that all 3 measurements of proliferation were significantly associated with survival. However, the pHH3 mitotic index accounted for a larger proportion of variability in survival than standard mitotic count or MIB-1/Ki-67 labeling index. After adjusting for age, extent of resection, and performance score, the pHH3 mitotic index remained an independent predictor of survival. Thus, pHH3 staining provides a simple and reliable method for quantifying proliferative potential and for the stratification of patients with diffuse astrocytomas into typical grade II and III groups. These results also suggest that pHH3 staining may be a useful method in other neoplasms in which accurate determination of proliferation potential is relevant to tumor grading or clinical treatment decision-making.

Audit of histomorphology and immunohistochemistry of the brain tumors: Revisited in context to the WHO 2016 molecular classification

“…[1,2] Colman et al [3,4] studied PHH3 staining with MIB1 and found that the combination of both with regard to grade and prognosis was better which is concordant with our study, in which 36 glial tumors were positive for GFAP with PHH3 and corresponding Ki67 staining; however, the gemistocytic glioblastoma was negative for GFAP.…”

Comparative diagnostic and prognostic performances of the hematoxylin-eosin and phospho-histone H3 mitotic count and Ki-67 index in adrenocortical carcinoma

“…Therefore, apart from being a time-consuming exercise, assessment of mitotic figures in 50 high-power fields is often poorly reproducible among observers. Phospho-histone H3 immunostaining has been demonstrated to specifically detect mitotic figures in several human tumors 19,22,27,[30][31][32] but has never been tested in adrenocortical carcinomas, so far. This is surprising, as it is well known that the recognition of this tumor type largely relies on mitotic index evaluation, as one of the nine factors included in the Weiss Score 1 or in other diagnostic algorithms.…”

“…11,12 Phospho-histone H3 immunostaining has been shown to be a reliable and easy method for mitotic index evaluation in melanoma, with both diagnostic [13][14][15][16][17][18] and prognostic 17,[19][20][21] implications. Moreover, it has been also successfully applied in different neoplasms of the breast, [22][23][24][25][26] meninges, [27][28][29] brain, 30 lung, 31 soft tissues, [32][33][34] esophagus, 35 female genital tract, 36,37 prostate, 38 and urothelium, 39 as well as in cytology material from pancreatic endocrine tumors 40 and urothelial carcinoma. 41 The Ki-67 index represents an alternative method for assessing the proliferative potential in adrenocortical tumors and has already been shown to differentiate adrenocortical adenoma from carcinoma, [42][43][44][45][46][47][48][49] and to predict tumor behavior.…”

Immunodetection of phosphohistone H3 as a surrogate of mitotic figure count and clinical outcome in cutaneous melanoma

“…Thus, immunodetection of phosphohistone H3 has become a sensitive and specific marker of mitotic figures and correlates with outcome in a variety of different human tumor types, 9 including breast carcinoma, 10,11 colorectal adenocarcinoma, 12 ovarian serous adenocarcinoma, 13 pulmonary neuroendocrine carcinoma, 14 uterine smooth muscle tumors, 15 astrocytomas, 16 and meningiomas. 17 In melanoma, immunodetection of phosphohistone H3 has been shown to increase the sensitivity and accuracy for mitotic figure detection; it improves inter-observer variability; and it reduces the time required to identify mitoses in primary cutaneous and uveal melanomas.…”