Quality assessment of estrogen receptor and progesterone receptor testing in breast cancer using a tissue microarray-based approach.

Assessing hormone receptor status is an essential part of the breast cancer diagnosis, as this biomarker greatly predicts response to hormonal treatment strategies. As such, hormone receptor testing laboratories are strongly encouraged to participate in external quality control schemes to achieve optimization of their immunohistochemical assays. Nine Dutch pathology departments provided tissue blocks containing invasive breast cancers which were all previously tested for estrogen receptor and/or progesterone receptor expression during routine practice. From these tissue blocks, tissue microarrays were constructed and tested for hormone receptor expression. When a discordant result was found between the local and TMA result, the original testing slide was revised and staining was repeated on a whole-tissue block. Sensitivity and specificity of individual laboratories for testing estrogen receptor expression were high, with an overall sensitivity and specificity [corrected] of 99.7 and 95.4%, respectively. Overall sensitivity and specificity of progesterone receptor testing were 94.8 and 92.6%, respectively. Out of 96 discordant cases, 36 cases would have been concordant if the recommended cut-off value of 1% instead of 10% was followed. Overall sensitivity and specificity of estrogen and progesterone receptor testing were high among participating laboratories. Continued enrollment of laboratories into quality control schemes is essential for achieving and maintaining the highest standard of care for breast cancer patients.

Human epidermal growth factor receptor 2 overexpression and amplification in endoscopic biopsies and resection specimens in esophageal and junctional adenocarcinoma.

Human epidermal growth factor receptor 2 (HER2) is overexpressed in a subset of esophageal adenocarcinomas. Frequently, biopsy material is used for evaluation of HER2 status. The aim of the study was to determine if HER2 expression in preoperative endoscopic biopsies is representative for the entire tumor. Preoperative endoscopic biopsies and matched resection specimens were collected from 75 patients who underwent esophagectomy for esophageal adenocarcinoma. Immunohistochemical staining (IHC) on HER2 and dual-color in situ hybridization (ISH) were performed. HER2 status was determined by following a clinical algorithm, first determining HER2 overexpression on immunohistochemistry and, when equivocal (2+), determining HER2 amplification on ISH. Seventy-one of 75 (95%) biopsies and 69/75 (92%) resection specimens could be analyzed due to technical failure. HER2 positivity was seen in 18/71 (25%) biopsies and in 15/69 (22%) resection specimens. Overall, HER2 status in the biopsy was concordant with HER2 status in the resection specimen in 94% of cases. Interobserver agreement on IHC scoring for all three observers was 83% in biopsies and 85% in resection specimens. HER2 positivity was detected in 22% of esophageal adenocarcinomas. Although interobserver agreement was moderate, HER2 status of a primary tumor can be reliably determined based on the endoscopically obtained pretreatment biopsy.

Limited human epidermal growth factor receptor 2 discordance in metastatic breast cancer patients treated with trastuzumab, a population based study.

BACKGROUND: Accurate assessment of the human epidermal growth factor receptor 2 (HER2) in breast cancer is essential for proper treatment decisions. HER2 positivity confirmation rates in breast cancer trials by central testing pathology laboratories were reported to be approximately 85%. The aim of our study was to assess in a population based sample concordance of HER2 status in metastatic breast cancer (MBC) patients locally tested HER2 positive and treated with trastuzumab. Moreover cost-effectiveness of in situ hybridisation (ISH) in patients with an immunohistochemical score 3+ (IHC3+) was explored. METHODS: MBC patients treated between 2005 and 2009 with trastuzumab-based therapy in North East Netherlands were identified by a survey of hospital pharmacies. Primary tumour samples were retested centrally for HER2 status using 1 immunohistochemical (IHC) method and two methods using ISH on tissue micro-arrays. Potential discordant patients were retested on whole tumour slides. HER2 positivity was defined as: (1) ISH amplification (according to American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) clinical practice Guideline Update) and (2) when ISH failed an IHC score of 3+. Cost-effectiveness was estimated using potential ISH and treatment costs. RESULTS: HER2 status could be retested in 174 of 194 (90%) patients. The HER2 concordance rate was 87%. The 21 discordant patients were in the 67% due to primary HER2 testing with only IHC. Overall survival of HER2 discordant and concordant patients was not significantly different (18 versus 25months, p=0.131). Structural ISH in the case of IHC3+ has an estimated potential saving of €87,710 per 100 patients. CONCLUSION: HER2 concordance in a population based study is comparable to those described in selected populations. Discordance is mostly due to testing with only IHC. ISH in the case of IHC3+ is cost-effective.

Discordance in ERα, PR and HER2 receptor status across different distant breast cancer metastases within the same patient.

BACKGROUND: We studied discordance in estrogen receptor alpha (ERα), progesterone receptor (PR) and human epidermal growth factor receptor 2 (HER2) status between multiple distant metastases from the same breast cancer patient. MATERIAL AND METHODS: Multiple distant metastases from 55 female patients were stained for ERα, PR and HER2 by immunohistochemistry and in situ hybridization for confirmation of the HER2 status. RESULTS: Different metastatic sites within the same patient showed discordance in ERα receptor status in 7.3% or 10.9% of patients (using a 10% or 1% threshold for positivity, respectively). For PR, 29.1% or 30.9% of patients showed discordance. Taking ERα and PR together, 36.4% of cases (both thresholds) showed discrepancy between metastases. In 10.9% (10% threshold) or 14.5% of patients (1% threshold), such discordance could have clinical consequences with regard to hormonal treatment. For HER2, there was 3.6% discordance on the immunohistochemical level but 0% on the gene level. CONCLUSION: In a significant proportion of metastatic breast cancer patients, discordance in ERα and PR receptor status between different metastatic sites was observed. This implies that multiple metastases may need to be biopsied to optimally reassess receptors.

KRAS mutation analysis on low percentage of colon cancer cells: the importance of quality assurance.

KRAS mutation testing is mandatory for patients with metastatic colorectal cancer who are eligible for treatment with an epidermal growth factor receptor targeting agent, since tumors with a mutation are not sensitive to the drug. Several methods for mutation testing are in use and the need for external quality assurance has been demonstrated. An often little addressed but important issue in external quality assurance schemes is a low percentage of tumor cells in the test samples, where the analytical sensitivity of most tests becomes critical. Using artificial samples based on a mixture of cell lines with known mutation status of the KRAS gene, we assessed the reliability of a series of commonly used methods (Sanger sequencing, high resolution melting, pyrosequencing, and amplification refractory mutation system-polymerase chain reaction) on samples with 0, 2.5, 5, 10, and 15 % mutated cells. Nine laboratories throughout Europe participated and submitted a total of ten data sets. The limit of detection of each method differed, ranging from >15-5 % tumor cells. All methods showed a decreasing correct mutation call rate proportionally with decreasing percentage of tumor cells. Our findings indicate that laboratories and clinicians need to be aware of the decrease in correct mutation call rate proportionally with decreasing percentage of tumor cells and that external quality assurance schemes need to address the issue of low tumor cell percentage in the test samples.

Concordance in KRAS and BRAF mutations in endoscopic biopsy samples and resection specimens of colorectal adenocarcinoma.

BACKGROUND: KRAS testing is mandatory if anti-EGFR therapy is considered in patients with metastatic colorectal cancer (CRC). In addition, BRAF mutations seem to be an important negative prognostic factor. The aim of this study is to establish the concordance of KRAS and BRAF mutational status in paired biopsy and resection specimens of primary CRC using several analytic methods. METHODS: DNA was extracted from paraffin blocks of 126 CRC patients. KRAS codon 12/13 and BRAF V600E mutational status was assessed using high resolution melting (HRM), direct sequencing (DS) of the HRM polymerase chain reaction (PCR) product. In addition, the Therascreen Amplification Refractory Mutation System (ARMS)-Scorpion KRAS assay and BRAF pyrosequencing were employed; both assays claim to require less tumour cells in comparison with DS. RESULTS: KRAS and BRAF were found to be mutually exclusive. Mutation frequencies were 33.9% for KRAS, and for BRAF 19.0%, respectively. Concordance of KRAS mutational status between biopsy and resection specimens was 97.4% (ARMS), 98.4% (DS) and 99.2% (HRM), respectively. For BRAF concordance was 98.4% (Pyro, DS) and 99.2% (HRM). CONCLUSIONS: KRAS and BRAF mutational status of endoscopic biopsies and resection specimens of CRC showed a >95% concordance. Endoscopic biopsies can be confidently used for molecular analysis.

Reversible cardiac valvular disease in catastrophic antiphospholipid syndrome.

Catastrophic antiphospholipid syndrome (CAPS) is a severe form of antiphospholipid syndrome (APS). It frequently leads to multiorgan failure with an approximate mortality rate of 50%. The heart is involved in about 50% of the patients with CAPS. We report two cases with CAPS and severe heart manifestations, documented by echocardiography. Both women show regression of the valvular regurgitation under treatment. Valve replacement therapy was no longer necessary. In earlier studies and case reports, cardiac valve involvement had been characterised by valve thickening and vegetations. We suppose that (sometimes reversible) microvascular disturbances lead to valvular regurgitation via papillary muscle dysfunction and myocardial stunning.

An aid to the diagnosis of genetic disorders underlying adult-onset renal failure: a literature review.

Several genetic disorders can present in adult patients with renal insufficiency. Genetic renal disease other than ADPKD accounts for ESRD in 3% of the adult Dutch population. Because of this low prevalence and their clinical heterogeneity most adult nephrologists are less familiar with these disorders. As a guideline to differential diagnosis, we provide an overview of the clinical manifestations and the pathogenesis of the main genetic disorders with chronic renal insufficiency surfacing in adulthood and add an algorithm plus 4 tables. We also indicate where molecular genetics nowadays can be of aid in the diagnostic process. The following disorders are discussed by mode of inheritance: 1) Autosomal dominant: autosomal dominant polycystic kidney disease, nephropathies associated with uromodulin (medullary cystic disease and familial juvenile hyperuricemic nephropathy), renal cysts and diabetes syndrome, nail-patella syndrome, glomerulopathy with fibronectin deposits. 2) Not autosomal dominant: Nephronophthisis, Fabry disease, primary oxalosis, Adenine Phosphoribosyl Transferase deficiency, Alport syndrome, Lecithin-cholesterol acyltransferase deficiency, adult-onset cystinosis.

Number and proliferation of clara cells in normal human airway epithelium.

Experimental pathologic studies suggest that Clara cells are one of the types of airway stem cells but the proliferation of Clara cells in human lungs has not yet been examined. The purpose of this study was to assess in conducting airways of normal human lungs: (1) the number of Clara cells; and (2) the contribution of Clara cells to the proliferation compartment. Samples of histologic normal tissue were taken from seven lungs obtained by autopsy. A triple sequential (immuno)histochemical staining was performed, using MIB-1 as a proliferation marker and anti-CC10 for the identification of Clara cells; subsequently, a PAS stain was carried out as a marker for goblet cells, as these cells were reported to be CC10-immunoreactive in an unknown proportion. Clara cells were virtually absent in the proximal airway epithelium. The number of Clara cells in the terminal bronchioles was 11 +/- 3% (mean +/- SD) and in respiratory bronchioles 22 +/- 5%. The overall proliferation compartment of the conducting airway epithelium was 0.83 +/- 0.47%; the contribution of Clara cells was 9%. In the terminal bronchioles 15% of proliferating airway epithelial cells were Clara cells, and in the respiratory bronchioles this number increased to 44%. The contribution of Clara cells to the proliferation compartment of normal human tracheobronchial epithelium is substantial, demonstrating a role of the Clara cell in the maintenance of the normal epithelium of the distal conducting airways in humans.

Number and proliferation of basal and parabasal cells in normal human airway epithelium.

Two roles have been suggested for basal cells on the basis of studies performed with laboratory animals: (1) anchoring of the tracheobronchial epithelium; and (2) being the epithelial stem cell. Parabasal cells located just above the basal cells have also been shown to contribute to cell renewal. However, a systematic study of the composition and proliferation of basal and parabasal cells in normal human lungs is lacking. The aims of this study were to determine in normal human conducting-airway epithelium: (1) the number of basal and parabasal cells; and (2) the contribution of basal and parabasal cells to the proliferation fraction. Samples of histologically normal tissue, free of pulmonary disease, were taken from seven lungs obtained by autopsy. Immunohistochemical staining was performed with the primary antibody MIB-1 as a proliferation marker and the antikeratin antibody 34betaE12 as a marker for basal and parabasal cells. In the largest conducting airways (diameter >= 4 mm), the percentages of basal and parabasal cells were 31% and 7%, respectively; the contribution to the proliferation compartment was 51% for basal and 33% for parabasal cells. In the smallest airways (diameter < 0.5 mm), 6% of epithelial cells were basal cells, with a 30% contribution to the proliferation compartment, whereas parabasal cells were absent. The high fraction of basal and parabasal cells contributing to the proliferation compartment of normal human conducting-airway epithelium supports the theory that cells at or near the basement membrane are likely to be progenitor cells.

Number and proliferation of neuroendocrine cells in normal human airway epithelium.

Pulmonary neuroendocrine cells (PNECs) are ubiquitous in human adult airway epithelium, and are implicated in pulmonary disease as PNEC hyperplasia has been described in a great number of different pulmonary lesions. The purpose of this study was to determine the baseline quantity and proliferative fraction of adult PNECs in the conducting airway epithelium of normal lungs. Autopsy was performed within 6 h of death on 250 subjects. In 9 of 250 cases without pulmonary disease, seven sequential samples were taken from trachea down to respiratory bronchioles, fixed in formalin, and embedded in paraffin. After microwave pretreatment in citrate buffer, sequential immunohistochemical staining was carried out, using MIB-1 (antibody directed against recombinant parts of the Ki-67 antigen) as marker for the proliferation fraction and chromogranin-A (CgA) for the identification of PNECs. Quantification of all epithelial cells of the conducting airways, MIB-1, and CgA immunoreactive cells, and length of basement membrane was interactively performed using image analysis. The results show that microwave treatment significantly enhances the sensitivity of CgA without loss of specificity. In total, 326,500 epithelial cells and 105 cm of basement membrane (BM) length were counted (3,101 cells/cm BM). The proliferation fraction of all epithelial cells was 0.76 +/- 0.53% (mean +/- SD). No mitosis was seen. The mean quantity of PNECs was 0.41 +/- 0.17% of all epithelial cells (12.5 cells/cm BM). Many dendritic PNEC processes parallel to the basement membrane could be appreciated between adjacent epithelial cells. No difference in the number of PNECs was found between large and small conducting airways. PNECs were not observed in the alveoli. Only 13 PNECs were immunoreactive for MIB-1; the proliferative fraction of PNECs was 1 to 2%. In histologically normal adult human conducting airway epithelium, the average overall proliferation fraction is 0.76%. The proliferation fraction of PNECs is equal to the overall proliferative fraction. The fraction of PNECs is 0.41%, using anti-CgA antiserum after microwave pretreatment of slides, 12 times more than previously reported. Many dendritic neuroendocrine cell processes were seen between non-neuroendocrine epithelial cells adjacent to the basement membrane. The widely held belief that neuroendocrine cells are of little importance in the adult lung is contradicted by the relative high density of PNECs and its cytoplasmic processers.

Neuroendocrine-specific protein C (NSP-C): subcellular localization and differential expression in relation to NSP-A.

A mouse monoclonal antibody RNL-4, as well as rabbit polyclonal antiserum POL-8 were raised against a synthetic peptide, encompassing the first twenty unique amino-terminal amino acid residues of NSP-C. The specificity of both immunoreagents was established in an ELISA assay using the synthetic peptide and by their immunoreactivity to NSP-C fusion proteins. Immunofluorescence analysis of COS-1 cells, transfected with NSP-C cDNA, showed staining of the endoplasmic reticulum with RNL-4 and POL-8. No cross-reactivity of these reagents with NSP-A or NSP-B was seen. Immunohistochemical studies in normal human tissues showed expression of NSP-C in tissues of neural and neuroendocrine origin, i.e. neurons of the central and peripheral nervous system, the neurohypophysis, adrenal medulla, adenohypophysis, pars intermedia, and in sporadic neuroedocrine cells of the lung. Expression of NSP-C was found in several small cell lung cancer (SCLC) cell lines, in non-SCLC cell lines with neuroendocrine features, but not in typical non-SCLC cell lines. Also, in a neuroblastoma cell line NSP-C expression was observed. Immunoblotting and immunoprecipitation studies with RNL-4 and POL-8 identified the 23 kDa NSP-C polypeptide in these cell lines. Immunofluorescence microscopy showed that also in these cell lines NSP-C is located at the endoplasmic reticulum, as shown before for NSP-A and NSP-B. In some of the cell lines coexpression of NSP-A and NSP-C was observed, while in others only one of the two could be detected. The differential expression of NSP-A and NSP-C in these cell lines is confirmed by immunoblotting and was also evident at the mRNA level. When NSP-A and NSP-C were coexpressed, the number of NSP-C-positive cells was always less than the number of NSP-A-positive cells. A partial colocalization of NSPs was observed in the endoplasmic reticulum. Cell fractionation studies revealed that both proteins are retained in the membranous fraction of the cell, from which they can be solubilized by Triton X-100. Immunoprecipitation analyses under native conditions indicate that NSP-C does not need to associate with NSP-A to form high molecular weight NSP-reticulons.

P53 in squamous metaplasia: a marker for risk of respiratory tract carcinoma.

Dysplasia in squamous metaplasia of the respiratory tract was believed to be a reversible premalignant lesion. Recently, presumably irreversible genetic alterations have been demonstrated in squamous metaplasia with dysplasia in lung-resection specimens. The genetic alterations were closely similar to those in adjacent bronchial carcinoma. There remains the question of which changes in squamous metaplastic lesions are premalignant, and which of these changes predict the occurrence of carcinoma of the respiratory tract. The purpose of this study was to determine the positive predictive value for respiratory-tract malignancy of the grade of dysplasia, p53 immunoreactivity, proliferative activity, and Bcl-2 in bronchial biopsy specimens exhibiting squamous metaplasia. Bronchial biopsies of 51 patients with squamous metaplasia diagnosed between 1982 and 1993 were used. Immunohistochemistry was done after microwave pretreatment of the biopsy specimens. Only unequivocally stained nuclei were counted. Normal bronchial epithelium obtained from autopsies was used as a control. In 31 patients, a synchronous or metachronous carcinoma was present (61%). Positive p53 immunoreactivity was found in 22 of the 51 patients (43%). The positive predictive values of p53 and of a high grade of dysplasia for carcinoma of the respiratory tract were 91% and 80%, respectively. Although the hyperproliferative state of squamous metaplastic lesions was clearly established, neither the percentage of MIB-1 labelling nor the mitotic index distinguished patient groups with and without carcinoma. No increased Bcl-2 immunostaining was found in squamous metaplasia. In conclusion, p53 immunoreactivity in squamous metaplastic lesions in bronchial biopsies is a marker of carcinoma of the respiratory tract.