Search

Ki67 has potential clinical importance in breast cancer but has yet to see broad acceptance due to inter-laboratory variability. Here we tested an open source and calibrated automated digital image analysis (DIA) platform to: (i) investigate the comparability of Ki67 measurement across corresponding core biopsy and resection specimen cases, and (ii) assess section to section differences in Ki67 scoring. Two sets of 60 previously stained slides containing 30 core-cut biopsy and 30 corresponding resection specimens from 30 estrogen receptor-positive breast cancer patients were sent to 17 participating labs for automated assessment of average Ki67 expression. The blocks were centrally cut and immunohistochemically (IHC) stained for Ki67 (MIB-1 antibody). The QuPath platform was used to evaluate tumoral Ki67 expression. Calibration of the DIA method was performed as in published studies. A guideline for building an automated Ki67 scoring algorithm was sent to participating labs. Very high correlation and no systematic error (p = 0.08) was found between consecutive Ki67 IHC sections. Ki67 scores were higher for core biopsy slides compared to paired whole sections from resections (p ≤ 0.001; median difference: 5.31%). The systematic discrepancy between core biopsy and corresponding whole sections was likely due to pre-analytical factors (tissue handling, fixation). Therefore, Ki67 IHC should be tested on core biopsy samples to best reflect the biological status of the tumor.

Aims: The nuclear proliferation marker Ki67 assayed by immunohistochemistry has multiple potential uses in breast cancer, but an unacceptable level of interlaboratory variability has hampered its clinical utility. The International Ki67 in Breast Cancer Working Group has undertaken a systematic programme to determine whether Ki67 measurement can be analytically validated and standardised among laboratories. This study addresses whether acceptable scoring reproducibility can be achieved on excision whole sections. Methods and results: Adjacent sections from 30 primary ER+ breast cancers were centrally stained for Ki67 and sections were circulated among 23 pathologists in 12 countries. All pathologists scored Ki67 by two methods: (i) global: four fields of 100 tumour cells each were selected to reflect observed heterogeneity in nuclear staining; (ii) hot‐spot: the field with highest apparent Ki67 index was selected and up to 500 cells scored. The intraclass correlation coefficient (ICC) for the global method [confidence interval (CI) = 0.87; 95% CI = 0.799–0.93] marginally met the prespecified success criterion (lower 95% CI ≥ 0.8), while the ICC for the hot‐spot method (0.83; 95% CI = 0.74–0.90) did not. Visually, interobserver concordance in location of selected hot‐spots varies between cases. The median times for scoring were 9 and 6 min for global and hot‐spot methods, respectively. Conclusions: The global scoring method demonstrates adequate reproducibility to warrant next steps towards evaluation for technical and clinical validity in appropriate cohorts of cases. The time taken for scoring by either method is practical using counting software we are making publicly available. Establishment of external quality assessment schemes is likely to improve the reproducibility between laboratories further. [ABSTRACT FROM AUTHOR]

After all, biomarkers such as estrogen receptor (ER) in breast cancer were scored in a threshold manner, with the assumption that this scoring was highly accurate and reproducible. Keywords: image analysis; breast cancer; estrogen receptor EN image analysis breast cancer estrogen receptor 767 768 2 02/06/23 20221101 NES 221101 At the time of publication of this article, image analysis as applied to diagnostic surgical pathology was a nascent technology, often characterized as a "solution in search of a problem." Today, while commercial image analysis hardware and software are legion, free public domain software such as QuPath can yield comparable results as many commercial software packages[3] and far exceed the capabilities of Photoshop. [Extracted from the article]

This review summarizes the three major breast-associated markers that can be of assistance in evaluating metastatic carcinomas for which a breast primary diagnosis is entertained. These markers include gross cystic disease fluid protein-15 (GCDFP-15), mammaglobin, and GATA3. The first two are cytoplasmic markers that show comparable sensitivities for breast cancer, although relatively few of the published studies have employed the same antibodies against the target molecule, making direct comparisons challenging. GATA3 is a nuclear transcription factor that shows superior sensitivity to GCDFP-15 and mammaglobin. However, the specificity of GATA3 can pose challenges, inasmuch as carcinomas of the bladder and other sites can show significant levels of positivity. Determination of the optimal panel of antibodies employed in a given clinical setting will thus depend on the non-breast tumours included in the differential diagnosis. [ABSTRACT FROM AUTHOR]

Context Testing for HER-2 oncogene in breast cancer has increased because of its role as a prognostic and predictive factor. Some advocate gene testing by fluorescence in situ hybridization (FISH) vs protein testing by immunohistochemistry as the method which most accurately evaluates and predicts response to the anti–HER-2 antibody, trastuzumab. However, critical examination of FISH on a screening basis has yet to be performed. Objectives To determine the correlation between FISH and immunohistochemistry results by determining HER-2/neu gene status on tumor sections with indeterminate immunohistochemistry results (2+ score), confirm gene amplification on tumor sections with positive results (3+ score), and verify gene status on tumor sections with negative results (0 or 1+ score). Design, Setting, and Patients A quality control and quality assurance program for HER-2 testing by FISH, which used tumor specimens from 2963 patients (median age, 56 years) with breast cancer received from 135 hospitals and cancer centers in 29 states, was performed at a reference laboratory from January 1, 1999, to May 15, 2003. Every specimen evaluated by FISH was parallel tested with immunohistochemistry tests. Main Outcome Measures With FISH as the presumed standard testing method, the positive and negative predictive values and sensitivity and specificity of immunohistochemistry were calculated. Results A total of 3260 clinical HER-2 tests by FISH were performed on 2963 serially referred breast cancer specimens. Of these, 2933 tests were successful and 2913 breast cancer specimens had both FISH and immunohistochemistry results available. With FISH as the standard testing method, the positive predictive value of positive immunohistochemistry score (3+) was 91.6%, and the negative predictive value of negative immunohistochemistry score (0 or 1+) was 97.2%. The sensitivity of immunohistochemistry tests, including tumor sections with scores of 2+ or 3+, was 92.6% and the speci... [ABSTRACT FROM AUTHOR]

Considers the role of pathologists in the molecular targeted therapy of cancer. Role of pathologists in molecular oncodiagnostics; Accuracy and precision in HER-2 testing in breast cancer; Kinase inhibitors for the targeted treatment of cancers; Predictive and prognostic implications of EGFR mutations in non-small cell lung cancer.

Context.--Numerous immunohistochemical stains have been shown to exhibit exclusive or preferential positivity in breast myoepithelial cells relative to their luminal/epithelial counterparts. These myoepithelial markers provide invaluable assistance in accurately classifying breast proliferations, especially in core biopsies. Although numerous myoepithelial markers are available, they differ in their sensitivity, specificity, and ease of interpretation, which may be attributed, to a large extent, to the variable immunoreactivity of these markers in stromal cells including myofibroblasts, vessels, luminal/epithelial cells, and tumor cells. Objective.--To review commonly used myoepithelial markers in breast pathology and a selection of diagnostic scenarios where they may be useful. Data Sources.--The information outlined in this review article is based on our experiences with routine cases and a review of English-language articles published between 1987 and 2008. Conclusions.--To demonstrate the presence or absence of myoepithelial cells, a panel-based approach of 2 or more markers is recommended. Markers that most effectively combine sensitivity, specificity, and ease of interpretation include smooth muscle myosin heavy chains, calponin, p75, p63, P-cadherin, basal cytokeratins, maspin, and CD10. These markers, however, display varying cross-reactivity patterns and variably reduced expression in the myoepithelial cells bordering in situ carcinomas. The choice of a myoepithelial marker should be dependent on a combination of factors, including published evidence on its diagnostic utility, its availability, performance characteristics that have been achieved in a given laboratory, and the specific diagnostic scenario. When its use is deemed necessary, immunohistochemistry for myoepithelial cells in breast pathology is most effective when conceptualized as supplemental, rather than central to routine morphologic interpretation. [ABSTRACT FROM AUTHOR]