A UK NEQAS ISH multicenter ring study using the Ventana HER2 dual-color ISH assay

We performed a multicenter assessment of a new HER2 dual-color chromogenic in situ hybridization (CISH) test and herein report on concordance of CISH data with fluorescence in situ hybridization (FISH) data and intraobserver and interlaboratory scoring consistency. HER2 results were evaluated using duplicate cores from 30 breast cancers in 5 laboratories using the Ventana HER2 dual-color ISH assay (Ventana Medical Systems, Cambridgeshire, England) and in 1 central laboratory using a standard FISH assay. Overall 93.3% of cases were successfully analyzed by CISH across the 5 participating laboratories. There was excellent concordance (98.0% overall) for diagnosis of HER2 amplification by CISH compared with FISH. Intraobserver variability (7.7%) and intersite variability (9.1%) of absolute HER2/chromosome enumeration probe 17 ratios were tightly controlled across all participating laboratories. The Ventana HER2 dual-color ISH assay is robust and reproducible, shows good concordance with a standard FISH assay, and complies with requirements in national and international guidelines for performance of ISH-based diagnostic tests.

Abstract P3-10-21: Audit of the Accuracy of Immunohistochemical (IHC) Testing of HER2 Status of Breast Cancer in the United Kingdom: An Interim Analysis

Background: The analysis of the level and distribution of HER2 protein expressed by cancer cells (HER2 status) is of great clinical value in the management of breast cancer patients both for the determination of the prognosis of disease and for identification of those patients who are eligible for anti-HER2 therapy. Accurate assessment of the HER2 status is essential for identifying patients which will benefit from HER2 targeted therapy. HER2 status in the UK is established using a two tier strategy with IHC as the initial test and subsequent reflex of equivocal results to in situ hybridization (ISH). IHC staining of the HER2 protein is graded as 0- 3+ dependent upon the intensity of staining, cellular localisation and the percentage of cells positive in accordance with CAP/ASCO and UK guidelines. HER2 3+ cases are considered as positive, with HER2 2+ cases (equivocal) retested by ISH to ascertain the gene amplification status. Cases that are scored as 0 and 1+ by IHC have no additional testing and are classed as negative. The literature indicates that a subset of these IHC negative cases show HER2 gene amplification by FISH (range 1.1-10.7%). The aim of this audit is to evaluate the discordance rate of HER2 IHC negative, FISH positive breast cancer in the UK, with a secondary objective to resolve if this is related to the choice of antibody used. Materials and methods: This audit selected a total of 1000 sequential cases reported as HER2 negative on IHC, from three UK reference centres receiving cases from 29 different hospitals. The cases were given a unique identifying number and annonymised. Each of the three centres used a different IHC method for frontline HER2 testing with centre one using HercepTest™ (DAKO), centre two Pathway 4B5 (Roche), and centre three, Oracle (Leica Microsystems). HER2 gene amplification status was determined using dual colour FISH analysis, PathVysion (ABBOTT) fluorescence ISH (FISH) in a single centre to provide standardised methodology and assessment. HER2 was classed as amplified when the HER2/cep 17 ratio was two or greater in accordance with UK guidelines. All cases which showed discordance between IHC and FISH were retested with each of the HER2 IHC platforms to discover whether these are truly discordant results or if the discrepancy is a consequence of the choice of antibody.

Results: An interim analysis of 170 cases shows an overall IHC negative/FISH positive discordance rate of 2.37%. The discordance rate per antibody was 1.7% for HercepTest, 3.3% with 4B5 and 2.5% with Oracle. Of the FISH positive cases the HER2/cep 17 ratios ranged from 2.2 - 6.17. The overall discordance rate between IHC negative and FISH positive is in keeping with the literature and is comparable between the three IHC platforms.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P3-10-21.

Abstract P2-06-19: Transferrin Receptor (CD71) Identifies Poor Response to Tamoxifen in Oestrogen Receptor Positive Breast Cancer Patients

Background: CD71 is involved in the cellular uptake of iron and is expressed on cells with high proliferation. Interestingly, we have Interestingly, we shown that its expression is associated with elevated tumour proliferation, shortened breast cancer specific survival and worsened outlook in ER+ adjuvant tamoxifen treated early breast cancer patients (Habashy et al, 2010). Here we extend our studies of the relationship between CD71 and tamoxifen outcome by study of an exploratory series of patients where endocrine response was directly assessable.

Material and Methods: CD71 (clone 10F11 antibody; Abcam, Cambridge, UK) and proliferation (MIB1) immunohistochemistry were performed as described in Habashy et al (2010) on 87 formalin fixed paraffin-embedded breast cancers. These were obtained from patients within the Nottingham Tenovus Multiple Antibody Study who had received systemic tamoxifen therapy for locally advanced primary carcinoma or metastatic disease or for recurrence after surgery alone. All had lesions assessable for response quality at 6 months, with survival and duration of antihormone response measured from initiation of antihormone to death or progression on therapy respectively. 48 tumours were classified as ER+ and 39 ER-. Results: Within this tamoxifen treated series, 68/87 patients were deemed positive for CD71 (plasma membrane and cytoplasmic), showing HScore values >=5. In the ER+ subgroup, a greater clinical response rate to tamoxifen was seen in CD71 — tumours (10 CR/PR, 3 S and 2 P) versus their CD71+ counterparts (CR/PR, 11 S and 16 P, p=0.015). CD71 positivity was associated with a significantly shortened time to progression and death (Kaplan Meier Test, p=0.026 and p=0.005 respectively). Examination of the proliferation marker MIB1 in ER+ tumours revealed a positive association with CD71 expression (Spearman's Test, p=0.01). In ER-patients, comprising predominantly progressive disease on tamoxifen therapy, CD71 status showed no impact on either time to progression of the disease or death.

Discussion: The present study extends our novel findings relating CD71 expression to loss of response to tamoxifen in ER+ breast cancer and reveals CD71 associates with increased tumour cell proliferation in clinical disease. Whether CD71 plays a causative role in the direction of these events and can be targeted to improve endocrine response requires to be ascertained.

Habashy HO et al, 2010, Breast Cancer Research and Treatment 119:283-293

Abd El-Rehim DM et al, 2005, Int J Cancer 116: 340-350

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P2-06-19.

The amplification of polymerized diaminobenzidine with physical developers: sensitizing effects of transition metal salts and sulphide

Amplification of metal-complexed polymerized diaminobenzidine by two light-insensitive physical developers was systematically examined in a dot blot model system following either polymerizing diaminobenzidine in the presence of transition metal salts or applying the metal salts post-diaminobenzidine polymerization. The effect of sodium sulphide treatment on subsequent amplification was also investigated. Those metal-diaminobenzidine complexes that facilitated the most powerful amplification were subsequently tested in an immunohistochemical setting. The most dramatic amplification of polymerized diaminobenzidine was observed following its post-polymerization treatment with salts of platinum alone, or gold or vanadium with subsequent sulphide treatment, and allowed previously invisible quantities of polymerized diaminobenzidine to be clearly seen. Three other transition metal salts also improved the amplification of polymerized diaminobenzidine but to a lesser degree, namely nickel alone, and silver or rhodium with subsequent sulphide treatment. Sensitivity was comparable with the colloidal gold-silver amplification system.

External Quality Assurance Schemes: The Impact of Participation in the UK Versus Rest of the World: 5 Year Data from the UK National External Quality Assurance Scheme

The American Society of Clinical Oncology/College of American Pathologists guidelines highlighted the critical importance of quality assurance in diagnostic testing for HER2.Unstained formalin-fixed, paraffin-embedded human breast carcinoma cell line sections were circulated to scheme participants on 15 occasions over 5 years. “Reference laboratories” reported results for the HER2/chromosome 17 ratio and HER2 copy number for 5 years for each cell line. Results from the 5th years participants (3 runs 13, 14, 15) were assessed for the pass rate in UK versus rest of the world (EU, US, Asia, etc). The number of participants was 76-78 laboratories/run (UK 30-35, ROW 43-46).Results: The percentage of laboratories achieving “appropriate” results ranged from 78-82% overall. Significantly higher performance was observed over 3 runs for UK laboratories (91-97%, “appropriate” results) versus ROW laboratories (67-74% “appropriate” results), p = 0.004. All methods used by scheme participants in UK Laboratories had excellent performance rates (Pathvysion, PharmDx, Ventana SISH/Inform, Kreatech Posieden). However in the ROW there was evidence of poor performance, which may be related to the assay format, although numbers of comparisons are relatively small.Participation in external quality assurance schemes is a valuable mechanism for evaluation and benchmarking of performance between laboratories. It also serves to improve consistency of HER2 testing by in situ hybridization. Using data from the UK NEQAS scheme we identified that laboratories whose performance is monitored and linked to an intergrated corrective action component(UK laboratories) perform consistently better than laboratories where performance data alone is provided (ROW). In the UK both participation and adequate performance in a national EQA scheme is required for laboratory accreditation. Whilst, in the context of robust EQA there is no evidence that different methods affect performance, in the ROW implementation of some assays appears sub-optimal. This poor performance does not, however, identify fundamental flaws with these methods, which are currently very well controlled amongst UK users but suggests greater attention to EQA results and change to improve laboratory performance is required in the rest of the world.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6010.

Prelminary Results of a NEQAS Ring Study Evaluating the Ventana INFORM™ HER2 Dual Colour Single Slide ISH Assay

Background: Recent innovations in HER2 testing include the development of novel chromogenic in situ hybridisation tests. Most countries use FISH or ISH based testing for HER2 gene amplification in equivocal (IHC 2+) cases. Data on the reproducibility and portability of novel and even established HER2 ISH methods is sparse. We report initial results from the multicentre evaluation of intra and inter-observer/site variation in scoring HER2 results from 30 breast cancers measured in 5 laboratories using the Ventana Dual colour ISH assay.Methods: A commercially available tissue micro-array (TMA; Stretton Scientific UK) containing 2 replicate cores from 30 breast cancers was circulated to 5 UK NEQAS reference laboratories (numbered 1-5). All laboratories performed chromogenic ISH using a 60 core TMA and reported results for all assessable cores. For all cases 20 cells were scored and a further 20 cells scored on a separate occasion to check intra-observer variation. Results were collated centrally and compared with FISH peformed in a single laboratory. Concordance between FISH and CISH is reported on a core by core and case by case analysis. Intra and inter-observer variation between laboratories is also assessed. Finally regression analysis comparing results was performed. Results from a single laboratory are presented here and full results will be available for the meeting.Results: 93% of cores were successfully analysed by the Ventana dual colour ISH assay. 87% of cores were successfully analysed by PathyVision® FISH CISH was concordant with FISH in 96.4% of cores evaluated. In one sample FISH results were 2.05 & 1.93 vs CISH of 2.03 and 2.14. In a second sample FISH results were 1.60 & 1.53 versus CISH results of 2.00 & 1.65. When mean results were calculated (2 cores per case) concordance between FISH and CISH results for this laboratories was 96.7% (1 discordant case – mean FISH – 1.99, mean CISH 2.09). 48 cores were scored twice (20 cells x 2) by a single observer. Mean intra-observer variation (for HER2 ratio) was 1.72% (Range 0.0-7.42%). No difference in scores was observed for the first vs second 20 cells. Scoring 40 cells produced no advantage. For results from a single observer for 2 cores (intra-site variation) from 42 core pairs (each core counted twice) variation was 7.5%.Conclusions: Preliminary evidence from the current study suggest that the Ventana INFORM™ HER2 dual colour single slide ISH assay can be robustly evaluated using conventional scoring approaches (20 cells per case). Concordance with FISH was excellent in the single laboratory reporting results to date. Further evidence will be reported from the other 4 participating laboratories.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6011.

Combined analysis of hypoxia-inducible factor 1 alpha and metallothionein indicates an aggressive subtype of colorectal carcinoma

PURPOSE

Hypoxia-inducible factor 1 (HIF-1) is a hypoxia-induced transcription factor that regulates gene expression in critical pathways involved in tumour growth and metastasis. Metallothionein (MT) is a group of small molecular weight cysteine-rich proteins with a broad variety of functions. The present study aimed to analyse the prognostic impact of HIF-1alpha and MT expression in colorectal cancer and to evaluate a possible link of combined HIF-1alpha and MT expression with colorectal cancer progression.

MATERIALS AND METHODS

We investigated the relationship of HIF-1alpha and MT with each other and clinicopathological parameters including proliferative activity (Ki67) and apoptosis (terminal desoxyribonucleotide transferase-mediated dUTP nick-end labelling) using immunohistochemistry.

RESULTS

HIF-1alpha expression was identified as an independent prognostic parameter in multivariate survival analysis and characterised an aggressive cancer phenotype. In addition, HIF-1alpha was significantly linked to an increased expression of MT.

CONCLUSIONS

HIF-1alpha expression qualified as an independent prognostic and characterised an aggressive cancer phenotype associated with an increased expression of MT. Our study suggests that MT can be added to the complex biological pathways induced by hypoxia in human cancer tissue.

Chromogenic in situ hybridization: a multicenter study comparing silver in situ hybridization with FISH

Our purposes were to perform a robust assessment of a new HER2 chromogenic in situ hybridization test and report on concordance of silver in situ hybridization (SISH) data with fluorescence in situ hybridization (FISH) data and on intraobserver and interlaboratory scoring consistency. HER2 results were scored from 45 breast cancers in 7 laboratories using the Ventana (Tucson, AZ) INFORM HER-2 SISH assay and in 1 central laboratory using a standard FISH assay. Overall, 94.8% of cases were successfully analyzed by SISH across the 6 participating laboratories that reported data. Concordance for diagnosis of HER2 amplification by SISH compared with FISH was high (96.0% overall). Intraobserver variability (8.0%) and intersite variability (12.66%) of absolute HER2/chromosome 17 ratios appear to be tightly controlled across all 6 participating laboratories. The Ventana INFORM HER-2 SISH assay is robust and reproducible, shows good concordance with a standard FISH assay, and complies with requirements in national guidelines for performance of diagnostic tests.

External quality assurance of HER2 FISH and ISH testing: three years of the UK national external quality assurance scheme

The American Society of Clinical Oncology/College of American Pathologists guidelines highlighted the critical importance of quality assurance in diagnostic testing for HER2. Unstained formalin-fixed, paraffin-embedded human breast carcinoma cell line sections were circulated to scheme participants on 9 occasions. "Reference laboratories" reported results for the HER2/chromosome 17 ratio and HER2 copy number for 3 years for each cell line, including 418 sets of results (1,671 results total). The number of participants was 62 laboratories in the final analysis. The mean and SD of results from reference laboratories demonstrated consistency during the 3-year period. The percentage of laboratories achieving "appropriate" results ranged from 45% to 88%, and the percentage achieving "inappropriate" results ranged from 5% to 29%. No consistent effect of the HER2 in situ hybridization testing method was demonstrated. Participation in external quality assurance schemes is a valuable mechanism for demonstrating and acquiring consistency for HER2 testing by in situ hybridization. Poor performance can be corrected via assistance and advice.

SV40 large T antigen-specific human T cell memory responses

The continued presence of simian virus 40 (SV40), a monkey polyomavirus, in man is confirmed by the regular detection of SV40-specific antibodies in 5-10% of children who are unlikely to have received contaminated polio-vaccines. The aim of our experiments was to find cellular immunological evidence of SV40 infection in humans by testing memory T cell responses to SV40 large T antigen (Tag). As there is some indication that the virus may be present in malignant pleural mesothelioma (MPM) cells, we analyzed T cell responses in MPM patients and in healthy donors. The frequencies of responding T cells to overlapping Tag peptides were tested by cytokine flow cytometry. CD8+ T cells from 4 of 32 MPM patients responded (above twofold of control) to SV40 Tag peptides, while no positive responses were detected in 12 healthy donors. Within SV40 Tag we identified three 15 amino acid-long immunogenic sequences and one 9 amino acid-long T cell epitope (p138) (138FPSELLSFL146), the latter including a HLA-B7-restriction motif. T cell responses to p138 were SV40-specific as T cells stimulated with p138 did not cross-react with the corresponding sequences of Tag of human polyomaviruses BKV and JCV. Similarly, the relevant BKV and JCV Tag peptides did not generate T cell responses against SV40 TAg p138. Peptide-stimulated T cells also killed SV40 Tag-transfected target cells. This article demonstrates the presence, and provides a detailed analysis, of SV40-specific T cell memory in man.

HER2 testing in the UK: further update to recommendations

These guidelines update the previous UK HER2 testing guidelines and have been formulated to give advice on methodology, interpretation and quality assurance to ensure that HER2 testing results are accurate, reliable and timely with the expansion of testing to all patients with breast cancer at the time of primary diagnosis. The recommendations for testing are the use of immunohistochemistry but with analysis of equivocal cases by in situ hybridisation to clarify their HER2 status or the use of frontline fluorescence in situ hybridisation (FISH) testing for those laboratories wishing to do so; the inclusion of a chromosome 17 probe is strongly recommended. Laboratories using chromogenic or silver in situ hybridisation should perform an initial validation against FISH. For immunohistochemistry and in situ hybridisation there must be participation in the appropriate National External Quality Assurance scheme.

Potential for false-positive staining with a rabbit monoclonal antibody to progesterone receptor (SP2): findings of the UK National External Quality Assessment Scheme for Immunocytochemistry and FISH highlight the need for correct validation of antibodies on introduction to the laboratory

This study focused on recent assessment results from the United Kingdom National External Quality Assessment Scheme for Immunocytochemistry and Fluorescence In-Situ Hybridisation breast hormone receptor module in which participants were asked to demonstrate progesterone receptors (PRs). The slides consisted of 3 infiltrating ductal breast carcinomas, previously classified as a high PR expresser, a moderate to low PR expresser, and a negative tumor. During this assessment, 2 commercial rabbit monoclonal antibodies, SP2 (Lab Vision/NeoMarkers, Fremont, CA), and 1E2 (Ventana, Tucson, AZ) were used by 15% of the participants. The SP2 rabbit monoclonal antibody showed false-positive and nonspecific staining on the previously established PR-tumor. This article highlights the necessity for all clinical laboratories to validate immunohistochemical methods and protocols when using newly marketed antibodies such as SP2; use composite tissue blocks with known levels of tumor expression such as a high, mid, and negative expression; and participate in internal and external quality assessment schemes, which can highlight potential technical issues in laboratory methods.

Combined expression of caveolin-1 and an activated AKT/mTOR pathway predicts reduced disease-free survival in clinically confined renal cell carcinoma

We previously reported that tumour-associated caveolin-1 is a potential biomarker in renal cell carcinoma (RCC), whose overexpression predicts metastasis following surgical resection for clinically confined disease. Much attention has recently focused on the AKT/mTOR pathway in a number of malignancies, including RCC. Since caveolin-1 and the AKT/mTOR signalling cascade are independently shown to be important regulators of tumour angiogenesis, we hypothesised that caveolin-1 interacts with the AKT/mTOR pathway to drive disease progression and metastasis in RCC. The aims of this study were to determine (i) the expression status of the activated AKT/mTOR pathway components (phosphorylated forms) in RCC and (ii) their prognostic value when combined with caveolin-1. Immunohistochemistry for caveolin-1, pAKT, pmTOR, pS6 and p4E-BP1 was performed on tissue microarrays from 174 clinically confined RCCs. Significantly decreased mean disease-free survival was observed when caveolin-1 was coexpressed with either pAKT (2.95 vs 6.14 years), pmTOR (3.17 vs 6.28 years), pS6 (1.45 vs 6.62 years) or p4E-BP1 (2.07 vs 6.09 years) than when neither or any one single biomarker was expressed alone. On multivariate analysis, the covariate of ‘caveolin-1/AKT’ (neither alone were influential covariates) was a significant influential indicator of poor disease-free survival with a hazard ratio of 2.13 (95% CI: 1.15–3.92), higher than that for vascular invasion. Tumours that coexpressed caveolin-1 and activated mTOR components were more likely to be larger, higher grade and to show vascular invasion. Our results provide the first clinical evidence that caveolin-1 cooperates with an activated AKT/mTOR pathway in cancer and may play an important role in disease progression. We conclude that evaluation of the ‘caveolin-1/AKT/mTOR axis’ in primary kidney tumours will identify subsets of RCC patients who require greater postoperative surveillance and more intensive treatment.

Human papilloma virus (HPV) prophylactic vaccination: Challenges for public health and implications for screening

Prophylactic vaccination against high risk human papilloma virus (HPV) 16 and 18 represents an exciting means of protection against HPV related malignancy. However, this strategy alone, even if there is a level of cross protection against other oncogenic viruses, cannot completely prevent cervical cancer. In some developed countries cervical screening programmes have reduced the incidence of invasive cervical cancer by up to 80% although this decline has now reached a plateau with current cancers occurring in patients who have failed to attend for screening or where the sensitivity of the tests have proved inadequate. Cervical screening is inevitably associated with significant anxiety for the many women who require investigation and treatment following abnormal cervical cytology. However, it is vitally important to stress the need for continued cervical screening to complement vaccination in order to optimise prevention in vaccinees and prevent cervical cancer in older women where the value of vaccination is currently unclear. It is likely that vaccination will ultimately change the natural history of HPV disease by reducing the influence of the highly oncogenic types HPV 16 and 18. In the long term this is likely to lead to an increase in recommended screening intervals. HPV vaccination may also reduce the positive predictive value of cervical cytology by reducing the number of truly positive abnormal smears. Careful consideration is required to ensure vaccination occurs at an age when the vaccine is most effective immunologically and when uptake is likely to be high. Antibody titres following vaccination in girls 12-16 years have been shown to be significantly higher than in older women, favouring vaccination in early adolescence prior contact with the virus. Highest prevalence rates for HPV infection are seen following the onset of sexual activity and therefore vaccination would need to be given prior to sexual debut. Since 20% of adolescents are sexually active at the age of 14 years, vaccination has been suggested at 10-12 years. However, parental concerns over the sexual implications of HPV vaccination may reduce uptake of vaccination thereby reducing the efficacy of an HPV vaccination programme. Concerns have already been raised over the acceptability of a vaccine preventing a sexually transmitted infection in young adolescents, particularly amongst parents or communities who consider their children to be at low risk of infection. This may be a particularly sensitive issue for ethnic minority groups. This paper considers the factors which will influence the efficacy of a public HPV vaccination programme and its impact on cervical screening.