Immunostaining of phospho-histone H3 and Ki-67 improves reproducibility of recurrence risk assessment of gastrointestinal stromal tumors

Abstract

Gastrointestinal stromal tumors (GISTs) are the most common non-epithelial tumors in the digestive tract. Beyond surgery, therapeutic management depends on risk of recurrence. Risk evaluation of GIST takes into account location and size of the tumor, whether or not the tumor was intact or ruptured and mitotic index. The mitotic index lacks in intra- and interobserver reproducibility. In this study, we evaluated on 61 GISTs, the reproducibility of mitotic counting using classical hematoxylin-eosin-saffron (HES) staining, and its correlation with the mitotic count obtained through immunohistochemical staining for phospho-histone H3 (PHH3) and the proliferation index based upon Ki-67 immunostaining. Mitotic counts by HES and PHH3 staining and Ki-67 proliferation index were evaluated twice by three independent observers taking into account interpretation times per tumor for each technique. HES-based and PHH3-based mitotic counts and Ki-67 proliferation index correlated well and presented good intra- and interobserver reproducibility. PHH3 staining resulted in a slight but statistically significant difference of about two more mitotic figures per 5 mm(2) than the HES-based count, which might have put some borderline tumors in a different risk category. Immunohistochemical staining for PHH3 and Ki-67 allowed more rapid interpretation than mitotic counts based upon HES staining, but only PHH3 staining allows counting of mitoses. Immunostaining using anti-PHH3 and anti-Ki-67 antibodies will eventually provide improved recurrence risk stratification of GIST and may become effective ancillary tools in deciding on optimal therapeutic management.

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.…”

Rebelled epigenome: histone H3S10 phosphorylation and H3S10 kinases in cancer biology and therapy

“…As histone H3S10 phosphorylation is involved in proliferation and transcriptional activation, it is not surprising that this epigenetic mark emerged as an important player in the initiation and propagation of cancer [ 15 – 18 ]. In addition, increase in H3S10ph was observed in and associated with poor prognosis in several cancers, including invasive breast cancer [ 19 , 20 ] esophageal squamous cell carcinoma [ 21 ], gastric cancer [ 22 , 23 ], glioblastoma [ 24 ], melanoma [ 25 , 26 ], nasopharyngeal carcinoma [ 18 ], and others.…”

Gastrointestinal Stromal Tumors Risk Stratification Utilizing Phospho-Histone H3 Evaluated by Manual Counting and Computer-Assisted Image Analysis

“…Ki-67 proliferation index was established by counting 500 consecutive cells and expressed as the percentage of stained nuclei. 16 Representative images of mitotic index and PHH3-positive cells are shown ( Figure 1) including cases with equal and different mitotic counting on the basis of H&E staining and PHH3 IHC.…”

“…10,13 Similarly, the value of PHH3 has also been reported in GIST risk stratification. 15,16 In recent years, rapid advancement in digital pathology with whole slide imaging has facilitated automated quantification of immunostained tissue sections. 17 Automated analysis leads to better validation and reproducibility of immunohistochemical analyses.…”