FAM19A4/miR124-2 Methylation Testing and Human Papillomavirus (HPV) 16/18 Genotyping in HPV-Positive Women Under the Age of 30 Years.

BACKGROUND: High-grade squamous intraepithelial lesions (HSIL) or cervical intraepithelial neoplasia (CIN) grade 2/3 lesions in human papillomavirus (HPV)-positive women <30 years of age have high spontaneous regression rates. To reduce overtreatment, biomarkers are needed to delineate advanced CIN lesions that require treatment. We analyzed the FAM19A4/miR124-2 methylation test and HPV16/18 genotyping in HPV-positive women aged <30 years, aiming to identify CIN2/3 lesions in need of treatment. METHODS: A European multicenter retrospective study was designed evaluating the FAM19A4/miR124-2 methylation test and HPV16/18 genotyping in cervical scrapes of 1061 HPV-positive women aged 15-29 years (690 ≤CIN1, 166 CIN2, and 205 CIN3+). A subset of 62 CIN2 and 103 CIN3 were immunohistochemically characterized by HPV E4 expression, a marker for a productive HPV infection, and p16ink4a and Ki-67, markers indicative for a transforming infection. CIN2/3 lesions with low HPV E4 expression and high p16ink4a/Ki-67 expression were considered as nonproductive, transforming CIN, compatible with advanced CIN2/3 lesions in need of treatment. RESULTS: FAM19A4/miR124-2 methylation positivity increased significantly with CIN grade and age groups (<25, 25-29, and ≥30 years), while HPV16/18 positivity was comparable across age groups. FAM19A4/miR124-2 methylation positivity was HPV type independent. Methylation-positive CIN2/3 lesions had higher p16ink4a/Ki-67-immunoscores (P = .003) and expressed less HPV E4 (P = .033) compared with methylation-negative CIN2/3 lesions. These differences in HPV E4 and p16ink4a/Ki-67 expression were not found between HPV16/18-positive and non-16/18 HPV-positive lesions. CONCLUSIONS: Compared with HPV16/18 genotyping, the FAM19A4/miR124-2 methylation test detects nonproductive, transforming CIN2/3 lesions with high specificity in women aged <30 years, providing clinicians supportive information about the need for treatment of CIN2/3 in young HPV-positive women.

Impact of Collection Volume and DNA Extraction Method on the Detection of Biomarkers and HPV DNA in First-Void Urine.

The potential of first-void (FV) urine as a non-invasive liquid biopsy for detection of human papillomavirus (HPV) DNA and other biomarkers has been increasingly recognized over the past decade. In this study, we investigated whether the volume of this initial urine stream has an impact on the analytical performance of biomarkers. In parallel, we evaluated different DNA extraction protocols and introduced an internal control in the urine preservative. Twenty-five women, diagnosed with high-risk HPV, provided three home-collected FV urine samples using three FV urine collection devices (Colli-Pee) with collector tubes that differ in volume (4, 10, 20 mL). Each collector tube was prefilled with Urine Conservation Medium spiked with phocine herpesvirus 1 (PhHV-1) DNA as internal control. Five different DNA extraction protocols were compared, followed by PCR for GAPDH and PhHV-1 (qPCR), HPV DNA, and HBB (HPV-Risk Assay), and ACTB (methylation-specific qPCR). Results showed limited effects of collection volume on human and HPV DNA endpoints. In contrast, significant variations in yield for human endpoints were observed for different DNA extraction methods (p < 0.05). Additionally, the potential of PhHV-1 as internal control to monitor FV urine collection, storage, and processing was demonstrated.

Classification of high-grade cervical intraepithelial neoplasia by p16ink4a , Ki-67, HPV E4 and FAM19A4/miR124-2 methylation status demonstrates considerable heterogeneity with potential consequences for management.

High-grade cervical intraepithelial neoplasia (CIN2 and CIN3) represents a heterogeneous disease with varying cancer progression risks. Biomarkers indicative for a productive human papillomavirus (HPV) infection (HPV E4) and a transforming HPV infection (p16ink4a , Ki-67 and host-cell DNA methylation) could provide guidance for clinical management in women with high-grade CIN. This study evaluates the cumulative score of immunohistochemical expression of p16ink4a (Scores 0-3) and Ki-67 (Scores 0-3), referred to as the "immunoscore" (IS), in 262 CIN2 and 235 CIN3 lesions derived from five European cohorts in relation to immunohistochemical HPV E4 expression and FAM19A4/miR124-2 methylation in the corresponding cervical scrape. The immunoscore classification resulted in 30 lesions within IS group 0-2 (6.0%), 151 lesions within IS group 3-4 (30.4%) and 316 lesions within IS group 5-6 (63.6%). E4 expression decreased significantly from CIN2 to CIN3 (P < .001) and with increasing immunoscore group (Ptrend < .001). Methylation positivity increased significantly from CIN2 to CIN3 (P < .001) and with increasing immunoscore group (Ptrend < .001). E4 expression was present in 9.8% of CIN3 (23/235) and in 12.0% of IS group 5-6 (38/316). Notably, in a minority (43/497, 8.7%) of high-grade lesions, characteristics of both transforming HPV infection (DNA hypermethylation) and productive HPV infection (E4 expression) were found simultaneously. Next, we stratified all high-grade CIN lesions, based on the presumed cancer progression risk of the biomarkers used, into biomarker profiles. These biomarker profiles, including immunoscore and methylation status, could help the clinician in the decision for immediate treatment or a "wait and see" policy to reduce overtreatment of high-grade CIN lesions.

Methylation markers FAM19A4 and miR124-2 as triage strategy for primary human papillomavirus screen positive women: A large European multicenter study.

In human papillomavirus (HPV) cervical cancer screening, cytology is used as triage to counter the low specificity of HPV testing. VALID-SCREEN is a EU-multicenter, retrospective study conducted to evaluate the clinical performance of the FAM19A4/miR124-2 methylation-based molecular triage test as a substitute or addition to cytology as reflex testing of HPV screen positive women. FAM19A4/miR124-2 methylation test (QIAsure Methylation Test) was evaluated in 2384 HPV-positive cervical screening samples, from women 29-76 years of age, derived from four EU countries. Specimens were collected in ThinPrep or SurePath media, HPV-status, concurrent cytology, and histology diagnosis were provided by the parent institutes. The control population consisted of women with no evidence of disease within 2 years of follow-up. A total of 899 histologies were retrieved; 527 showed no disease, 124 CIN2 (5.2%), 228 CIN3 (9.6%) and 20 cervical cancers (0.8%); 19 of 20 screen-detected cervical cancers were found methylation-positive (sensitivity 95%). Overall specificity of FAM19A4/miR124-2 methylation test was 78.3% (n = 2013; 95%CI: 76-80). The negative predictive value of hrHPV positive, methylation-negative outcomes were 99.9% for cervical cancer (N = 1694; 95%CI: 99.6-99.99), 96.9% for ≥CIN3 (95%CI: 96-98), and 93.0% for ≥CIN2 (95%CI: 92-94). Overall sensitivity for CIN3 using FAM19A4/miR124-2 methylation test was 77% (n = 228; 95%CI: 71-82). CIN3 sensitivity was uniform between centers independent of sample collection medias, DNA extraction methods and HPV screening tests. Being objectively reported compared to the subjectivity of cytology, equally performing across settings and screening methods, the FAM19A4/miR124-2 methylation constitute an alternative/supplement to cytology as triage method to be investigated in real-life pilot implementation.

Controlling technical variation amongst 6693 patient microarrays of the randomized MINDACT trial.

Gene expression data obtained in large studies hold great promises for discovering disease signatures or subtypes through data analysis. It is also prone to technical variation, whose removal is essential to avoid spurious discoveries. Because this variation is not always known and can be confounded with biological signals, its removal is a challenging task. Here we provide a step-wise procedure and comprehensive analysis of the MINDACT microarray dataset. The MINDACT trial enrolled 6693 breast cancer patients and prospectively validated the gene expression signature MammaPrint for outcome prediction. The study also yielded a full-transcriptome microarray for each tumor. We show for the first time in such a large dataset how technical variation can be removed while retaining expected biological signals. Because of its unprecedented size, we hope the resulting adjusted dataset will be an invaluable tool to discover or test gene expression signatures and to advance our understanding of breast cancer.

FAM19A4/miR124-2 methylation in invasive cervical cancer: A retrospective cross-sectional worldwide study.

Widespread adoption of primary human papillomavirus (HPV)-based screening has encouraged the search for a triage test which retains high sensitivity for the detection of cervical cancer and precancer, but increases specificity to avoid overtreatment. Methylation analysis of FAM19A4 and miR124-2 genes has shown promise for the triage of high-risk (hr) HPV-positive women. In our study, we assessed the consistency of FAM19A4/miR124-2 methylation analysis in the detection of cervical cancer in a series of 519 invasive cervical carcinomas (n = 314 cervical scrapes, n = 205 tissue specimens) from over 25 countries, using a quantitative methylation-specific PCR (qMSP)-based assay (QIAsure Methylation Test®). Positivity rates stratified per histotype, FIGO stage, hrHPV status, hrHPV genotype, sample type and geographical region were calculated. In total, 510 of the 519 cervical carcinomas (98.3%; 95% CI: 96.7-99.2) tested FAM19A4/miR124-2 methylation-positive. Test positivity was consistent across the different subgroups based on cervical cancer histotype, FIGO stage, hrHPV status, hrHPV genotype, sample type and geographical region. In conclusion, FAM19A4/miR124-2 methylation analysis detects nearly all cervical carcinomas, including rare histotypes and hrHPV-negative carcinomas. These results indicate that a negative FAM19A4/miR124-2 methylation assay result is likely to rule out the presence of cervical cancer.

Intra- and inter-laboratory agreement of the FAM19A4/mir124-2 methylation test: Results from an international study.

BACKGROUND: HPV-based cervical screening detects women at an increased risk of cervical cancer and precancer. To differentiate among HPV-positive women those with (pre)cancer, triage testing is necessary. The detection of cancer-associated host-cell DNA methylation (FAM19A4 and hsa-mir124-2) in cervical samples has shown valuable as triage test. This multicenter study from 6 collaborating European laboratories and one reference laboratory was set out to determine the intra- and inter-laboratory agreement of FAM19A4/mir124-2 DNA methylation analysis utilizing the QIAsure Methylation Test. METHODS: Agreement analysis for the QIAsure Methylation Test was assessed on high-risk HPV-positive cervical specimens (n = 1680) both at the level of the assay and at the full workflow, including bisulfite conversion. RESULTS: Intra- and inter-laboratory assay agreement were 91.4% (534/584; 95% CI 88.9-93.5; κ = 0.82) and 92.5% (369/399; 95% CI 90.0-94.7; κ = 0.83), respectively. The inter-laboratory workflow (bisulfite conversion and assay combined) agreement was 90.0% (627/697; 95% CI 87.5%-92.0%; κ = 0.76). CONCLUSION: These data show that the QIAsure Methylation Test performs robust and reproducible in different laboratory contexts. These results support the use of the QIAsure Methylation Test for full molecular screening for cervical cancer, including primary HPV testing and triage testing by methylation analysis.

Equivalence of MammaPrint array types in clinical trials and diagnostics.

MammaPrint is an FDA-cleared microarray-based test that uses expression levels of the 70 MammaPrint genes to assess distant recurrence risk in early-stage breast cancer. The prospective RASTER study proved that MammaPrint Low Risk patients can safely forgo chemotherapy, which is further subject of the prospective randomized MINDACT trial. While MammaPrint diagnostic results are obtained from mini-arrays, clinical trials may be performed on whole-genome arrays. Here we demonstrate the equivalence and reproducibility of the MammaPrint test. MammaPrint indices were collected for breast cancer samples: (i) on both customized certified array types (n = 1,897 sample pairs), (ii) with matched fresh and FFPE tissues (n = 552 sample pairs), iii) for control samples replicated over a period of 10 years (n = 11,333), and iv) repeated measurements (n = 280). The array type indicated a near perfect Pearson correlation of 0.99 (95 % CI: 0.989-0.991). Paired fresh and FFPE samples showed an excellent Pearson correlation of 0.93 (95 % CI 0.92-0.94), in spite of the variability introduced by intratumoral tissue heterogeneity. Control samples showed high consistency over 10 year's time (overall reproducibility of 97.4 %). Precision and repeatability are overall 98.2 and 98.3 %, respectively. Results confirm that the combination of the near perfect correlation between array types, excellent equivalence between tissue types, and a very high stability, precision, and repeatability demonstrate that results from clinical trials (such as MINDACT and I-SPY 2) are equivalent to current MammaPrint FFPE and fresh diagnostics, and can be used interchangeably.

Estrogen receptor splice variants as a potential source of false-positive estrogen receptor status in breast cancer diagnostics.

It is well established that only estrogen receptor (ER)-positive tumors benefit from hormonal therapies. We hypothesized that a subgroup of breast cancer patients expresses estrogen receptor α (ERα), but fails to respond to hormonal therapy due to the expression of a non-functional receptor. We analyzed a series of 2,658 ERα-positive HER2-negative breast tumors for ERα and progesterone receptor (PR) status as determined by mRNA expression and for their molecular subtypes (Luminal type vs Basal type, assessed by BluePrint™ molecular subtyping assay). In addition, we assessed the recurrence risk (low vs high) using the 70-gene MammaPrint™ signature. We found that 55 out of 2,658 (2.1 %) tumors that are ERα positive by mRNA analysis also demonstrate a Basal molecular subtype, indicating that they lack expression of estrogen-responsive genes. These ERα-positive Basal-type tumors express significantly lower levels of both ERα and PR mRNA as compared to Luminal-type tumors (P < 0.0001) and almost invariably (94.5 %) have a high-risk MammaPrint™ profile. Twelve of the MammaPrint™ genes are directly ERα responsive, indicating that MammaPrint™ assesses ERα function in breast cancer without considering ERα mRNA levels. We find a relatively high expression of the dominant negative ERα splice variant ERΔ7 in ERα-positive Basal-type tumors as compared to ERα-positive Luminal-type tumors (P < 0.0001). Expression of the dominant negative ERα variant ERΔ7 provides a rationale as to why tumors are of the Basal molecular subtype while staining ERα positive by immunohistochemistry. These tumors may lack a functional response to estrogen and consequently may not respond to hormonal therapy. Our data indicate that such patients are of MammaPrint™ high recurrence risk and might benefit from adjuvant chemotherapy.

Performance characteristics of the MammaPrint® breast cancer diagnostic gene signature.

BACKGROUND: The analytical performance of multigene signatures depends on many parameters, including precision, repeatability, reproducibility and intratumor heterogeneity. Indicators such as sensitivity, specificity, positive predictive value and negative predictive value are typically used to define the clinical performance of a diagnostic test. AIM: Here we study these performance characteristics of the MammaPrint® (Agendia NV, Amsterdam, The Netherlands) 70-gene signature using the US FDA-recommended guidelines, as well as predetermined acceptance criteria. RESULTS: The clinical and analytical performance characteristics show that MammaPrint is a robust, reproducible, precise test, with a maximum variation of 5% in multiple samplings of the same tissue. CONCLUSION: MammaPrint is a reliable indicator of distant metastasis in early-stage breast cancer patients of all ages and is well suited for personalized medical care.

Gene expression profiling guiding diagnosis and therapy of rare mammary-like anogenital gland carcinomas.

Cancers derived from anogenital mammary-like glands are rare, and their identification and selection of treatment for dissemination may be difficult. We encountered two such tumors, which both presented as occult primaries with nodal and hematogenous metastases. They were studied by immunohistochemistry, HER2 receptor assay, and gene expression profiling. Both tumors had some microscopical and immunohistochemical features in common with breast cancer, but lacked estrogen and progesterone receptors. Taxane-platinum-based systemic chemotherapy did not stop progression in a male patient, in whom a developing inguinal skin lesion was the likely primary tumor. The same regimen gave partial remission in a later, female, patient. After the mammary-like, HER2 positive nature of her tumor was confirmed by gene expression profiling using CupPrint and TargetPrint assays, treatment with vinorelbine-trastuzumab induced complete remission that is maintained by trastuzumab alone for almost 4 years after initial diagnosis. Molecular and immunohistochemical characterization of these rare tumors may identify them and sometimes guide systemic chemotherapy away from a non-specific and "broad spectrum" regimen toward a targeted therapy, resulting in greater effectiveness with less side effects.

Comparison of histopathological and gene expression-based typing of cancer of unknown primary.

For the clinical diagnosis and appropriate therapy of patients with cancer of unknown primary (CUP), biopsies of the tumor metastases are generally examined histopathologically and by immunohistochemistry (IHC). Gene expression profiling (GEP) is a new diagnostic technique that might further contribute to tumor specification. Biopsies of 43 CUP cases underwent a retrospective central histopathological and immunohistochemical review and centrally performed GEP using CupPrint(TM). Two samples could not be evaluated by IHC due to small biopsy size or loss of immunoreactivity. One of these and 17 other samples were not suited for GEP due to RNA degradation. In 13 out of the remaining 24 cases (54%), the same primary was proposed by IHC and GEP and was supported by the clinical findings, furthermore leading to the doubtless identification of the primary in four out of these. In seven cases, there was discordance between IHC and GEP, with the clinical picture being more in line with IHC in three and with GEP in four cases. Four cases had to remain undecided because the primary tumors suggested by IHC and GEP were not supported. In conclusion, overlap between IHC and GEP results and the clinical presentation was noted in the majority of those true CUP cases that were evaluable with both techniques. Therefore, GEP can be a complementary diagnostic technique assisting immunohistochemical profiling of cancer biopsies with unknown primary.

A gene expression profile for detection of sufficient tumour cells in breast tumour tissue: microarray diagnosis eligibility.

BACKGROUND: Microarray diagnostics of tumour samples is based on measurement of prognostic and/or predictive gene expression profiles. Typically, diagnostic profiles have been developed using bulk tumour samples with a sufficient amount of tumour cells (usually >50%). Consequentially, a diagnostic results depends on the minimal percentage of tumour cells within a sample. Currently, tumour cell percentage is assessed by conventional histopathological review. However, even for experienced pathologists, such scoring remains subjective and time consuming and can lead to ambiguous results. METHODS: In this study we investigated whether we could use transcriptional activity of a specific set of genes instead of histopathological review to identify samples with sufficient tumour cell content. Genome-wide gene expression measurements were used to develop a transcriptional gene profile that could accurately assess a sample's tumour cell percentage. RESULTS: Supervised analysis across 165 breast tumour samples resulted in the identification of a set of 13 genes which expression correlated with presence of tumour cells. The developed gene profile showed a high performance (AUC 0.92) for identification of samples that are suitable for microarray diagnostics. Validation on 238 additional breast tumour samples indicated a robust performance for correct classification with an overall accuracy of 91 percent and a kappa score of 0.63 (95%CI 0.47-0.73). CONCLUSION: The developed 13-gene profile provides an objective tool for assessment whether a breast cancer sample contains sufficient tumour cells for microarray diagnostics. It will improve the efficiency and throughput for diagnostic gene expression profiling as it no longer requires histopathological analysis for initial tumour percentage scoring. Such profile will also be very use useful for assessment of tumour cell percentage in biopsies where conventional histopathology is difficult, such as fine needle aspirates.

Implementation of a novel microarray-based diagnostic test for cancer of unknown primary.

Patients with carcinoma of unknown primary (CUP) present with metastatic disease for which the primary site cannot be found, despite extensive standard investigation. Here, we describe the development and implementation of the first clinically available microarray-based test for this cancer type (CUPPrint), based on 633 individual tumors representing 30 carcinoma and 17 noncarcinoma classes. Tissue of origin prediction for either fresh frozen or paraffin-embedded tumor samples is achieved with the use of a custom 8-pack 1.9k microarray and robust classification algorithm. An expression profile of 495 genes was used to predict tumor origin by applying a k-nearest neighbor algorithm. Internal cross-validation and analysis of an independent, previously published, 229-sample dataset revealed that clinically informative predictions were made for up to 94% of samples analyzed. Analysis of 13 previously published CUP specimens yielded predicted tumor origins that supported the clinical suspicion in 12 cases (92%). Microarray profiling presents a promising tool to assist in the identification of the primary tumor and might direct a more tailored treatment for CUP patients.

An immune response enriched 72-gene prognostic profile for early-stage non-small-cell lung cancer.

PURPOSE: Current staging methods are imprecise for predicting prognosis of early-stage non-small-cell lung cancer (NSCLC). We aimed to develop a gene expression profile for stage I and stage II NSCLC, allowing identification of patients with a high risk of disease recurrence within 2 to 3 years after initial diagnosis. EXPERIMENTAL DESIGN: We used whole-genome gene expression microarrays to analyze frozen tumor samples from 172 NSCLC patients (pT1-2, N0-1, M0) from five European institutions, who had undergone complete surgical resection. Median follow-up was 89 months (range, 1.2-389) and 64 patients developed a recurrence. A random two thirds of the samples were assigned as the training cohort with the remaining samples set aside for independent validation. Cox proportional hazards models were used to evaluate the association between expression levels of individual genes and patient recurrence-free survival. A nearest mean analysis was used to develop a gene-expression classifier for disease recurrence. RESULTS: We have developed a 72-gene expression prognostic NSCLC classifier. Based on the classifier score, patients were classified as either high or low risk of disease recurrence. Patients classified as low risk showed a significantly better recurrence-free survival both in the training set (P < 0.001; n = 103) and in the independent validation set (P < 0.01; n = 69). Genes in our prognostic signature were strongly enriched for genes associated with immune response. CONCLUSIONS: Our 72-gene signature is closely associated with recurrence-free and overall survival in early-stage NSCLC patients and may become a tool for patient selection for adjuvant therapy.

The 70-gene prognosis-signature predicts disease outcome in breast cancer patients with 1-3 positive lymph nodes in an independent validation study.

PURPOSE: The 70-gene prognosis-signature has shown to be a valid prognostic tool in node-negative breast cancer. Although axillary lymph node status is considered to be one of the most important prognostic factors, still 25-30% of node-positive breast cancer patients will remain free of distant metastases, even without adjuvant systemic therapy. We therefore investigated whether the 70-gene prognosis-signature can accurately identify patients with 1-3 positive lymph nodes who have an excellent disease outcome. METHODS: Frozen tumour samples from 241 patients with operable T1-3 breast cancer, and 1-3 positive axillary lymph nodes, with a median follow-up of 7.8 years, were selected from 2 institutes. Using a customized microarray, tumour samples were analysed for the 70-gene tumour expression signature. In addition, we reanalysed part of a previously described cohort (n = 106) with extended follow-up. RESULTS: The 10-year distant metastasis-free (DMFS) and breast cancer specific survival (BCSS) probabilities were 91% (SE 4%) and 96% (SE 2%), respectively for the good prognosis-signature group (99 patients), and 76% (SE 4%) and 76% (SE 4%), respectively for the poor prognosis-signature group (142 patients). The 70-gene signature was significantly superior to the traditional prognostic factors in predicting BCSS with a multivariate hazard ratio (HR) of 7.17 (95% CI 1.81 to 28.43; P = 0.005). CONCLUSIONS: The 70-gene prognosis-signature outperforms traditional prognostic factors in predicting disease outcome in patients with 1-3 positive nodes. Moreover, the signature can accurately identify patients with an excellent disease outcome in node-positive breast cancer, who may be safely spared adjuvant chemotherapy.

Gene expression profiling to identify the histogenetic origin of metastatic adenocarcinomas of unknown primary.

PURPOSE: Patients with adenocarcinoma of unknown primary origin (ACUP) constitute approximately 4% of all malignancies. For effective treatment of these patients, it is considered optimal to identify the primary tumor origins. Currently, the success rate of the diagnostic work-up is only 20% to 30%. Our goal was to evaluate the contribution of gene expression profiling for routine clinical practice in patients with ACUP. PATIENTS AND METHODS: Formalin-fixed, paraffin-embedded (FFPE) samples were obtained from 84 patients with a known primary adenocarcinoma and from 38 patients with ACUP. An extensive immunohistochemical panel classified 16 of the patients with ACUP, whereas 22 patients remained unclassified for their histogenetic origin. Information about staging procedures and clinical follow-up were available in all patient cases. The expression data were analyzed in relation to clinicopathologic variables and immunohistochemical results. RESULTS: The gene expression-based assay classified the primary site correctly in 70 (83%) of 84 patient cases of primary and metastatic tumors of known origin, with good sensitivity for the majority of the tumor classes and relatively poor sensitivity for primary lung adenocarcinoma. Gene expression profiling identified 15 (94%) of 16 patients with initial ACUP who were classified by immunohistochemistry, and it made a valuable contribution to a potential site of origin in 14 of the 22 patients with ACUP. CONCLUSION: The gene expression platform can classify correctly from FFPE samples the majority of tumors classes both in patients with known primary and in patients with ACUP. Therefore, gene expression profiling represents an additional analytic approach to assist with the histogenetic diagnosis of patients with ACUP.

Use of 70-gene signature to predict prognosis of patients with node-negative breast cancer: a prospective community-based feasibility study (RASTER).

BACKGROUND: A microarray-based 70-gene prognosis signature might improve the selection of patients with node-negative breast cancer for adjuvant systemic treatment. The main aims of this MicroarRAy PrognoSTics in Breast CancER (RASTER) study were to assess prospectively the feasibility of implementation of the 70-gene prognosis signature in community-based settings and its effect on adjuvant systemic treatment decisions when considered with treatment advice formulated from the Dutch Institute for Healthcare Improvement (CBO) and other guidelines. METHODS: Between January, 2004 and December, 2006, 812 women aged under 61 years with primary breast carcinoma (clinical T1-4N0M0) were enrolled. Fresh tumour samples were collected in 16 hospitals in the Netherlands within 1 h after surgery. Clinicopathological factors were collected and microarray analysis was done with a custom-designed array chip that assessed the mRNA expression index of the 70 genes previously identified for the prognostic signature. Patients with a "good" signature were deemed to have a good prognosis and, therefore, could be spared adjuvant systemic treatment with its associated adverse effects, whereas patients with a "poor" signature were judged to have a poor prognosis and should be considered for adjuvant systemic treatment. Concordance between risk predicted by the prognosis signature and risk predicted by commonly used clinicopathological guidelines (ie, St Gallen guidelines, Nottingham Prognostic Index, and Adjuvant! Online) was assessed. FINDINGS: Of 585 eligible patients, 158 patients were excluded because of sampling failure (n=128) and incorrect procedure (n=30). Prognosis signatures were assessed in 427 patients. The 70-gene prognosis signature identified 219 (51%) patients with good prognosis and 208 (49%) patients with poor prognosis. The Dutch CBO guidelines identified 184 patients (43%) with poor prognosis, which was discordant with those findings obtained with the prognosis signature in 128 (30%) patients. Oncologists recommended adjuvant treatment in 203 (48%) patients based on Dutch CBO guidelines, in 265 (62%) patients if the guidelines were used with the prognosis signature, and in 259 (61%) patients if Dutch CBO guidelines, prognosis signature, and patients' preferences for treatment were all taken into account. Adjuvant! Online guidelines identified more patients with poor prognosis than did the signature alone (294 [69%]), and discordance with the signature occurred in 160 (37%) patients. St Gallen guidelines identified 353 (83%) patients with poor prognosis with the signature and discordance in 168 (39%) patients. Nottingham Prognostic Index recorded 179 (42%) patients with poor prognosis with the signature and discordance in 117 (27%) patients. INTERPRETATION: Use of the prognosis signature is feasible in Dutch community hospitals. Adjuvant systemic treatment was advised less often when the more restrictive Dutch CBO guidelines were used compared with that finally given after use of the prognosis signature. For the other guidelines assessed, less adjuvant chemotherapy would be given when the data based on prognosis signature alone are used, which might spare patients from adverse effects and confirms previous findings. Future studies should assess whether use of the prognosis signature could improve survival or equal survival while avoiding unnecessary adjuvant systemic treatment without affecting patients' survival, and further assess the factors that physicians use to recommend adjuvant systemic treatment.

Robust interlaboratory reproducibility of a gene expression signature measurement consistent with the needs of a new generation of diagnostic tools.

BACKGROUND: The increasing use of DNA microarrays in biomedical research, toxicogenomics, pharmaceutical development, and diagnostics has focused attention on the reproducibility and reliability of microarray measurements. While the reproducibility of microarray gene expression measurements has been the subject of several recent reports, there is still a need for systematic investigation into what factors most contribute to variability of measured expression levels observed among different laboratories and different experimenters. RESULTS: We report the results of an interlaboratory comparison of gene expression array measurements on the same microarray platform, in which the RNA amplification and labeling, hybridization and wash, and slide scanning were each individually varied. Identical input RNA was used for all experiments. While some sources of variation have measurable influence on individual microarray signals, they showed very low influence on sample-to-reference ratios based on averaged triplicate measurements in the two-color experiments. RNA labeling was the largest contributor to interlaboratory variation. CONCLUSION: Despite this variation, measurement of one particular breast cancer gene expression signature in three different laboratories was found to be highly robust, showing a high intralaboratory and interlaboratory reproducibility when using strictly controlled standard operating procedures.

Converting a breast cancer microarray signature into a high-throughput diagnostic test.

BACKGROUND: A 70-gene tumor expression profile was established as a powerful predictor of disease outcome in young breast cancer patients. This profile, however, was generated on microarrays containing 25,000 60-mer oligonucleotides that are not designed for processing of many samples on a routine basis. RESULTS: To facilitate its use in a diagnostic setting, the 70-gene prognosis profile was translated into a customized microarray (MammaPrint) containing a reduced set of 1,900 probes suitable for high throughput processing. RNA of 162 patient samples from two previous studies was subjected to hybridization to this custom array to validate the prognostic value. Classification results obtained from the original analysis were then compared to those generated using the algorithms based on the custom microarray and showed an extremely high correlation of prognosis prediction between the original data and those generated using the custom mini-array (p < 0.0001). CONCLUSION: In this report we demonstrate for the first time that microarray technology can be used as a reliable diagnostic tool. The data clearly demonstrate the reproducibility and robustness of the small custom-made microarray. The array is therefore an excellent tool to predict outcome of disease in breast cancer patients.