Cost effectiveness of gene expression profiling for early stage breast cancer

Multigene assays and molecular markers in breast cancer: systematic review of health economic analyses

Breast cancer is the most common female cancer and is associated with a significant clinical and economic burden. Multigene assays and molecular markers represent an opportunity to direct chemotherapy only to patients likely to have significant benefit. This systematic review examines published health economic analyses to assess the support for adjuvant therapy decision making. Literature searches of PubMed, the Cochrane Library, and congress databases were carried out to identify economic evaluations of multigene assays and molecular markers published between 2002 and 2012. After screening and data extraction, study quality was assessed using the Quality of Health Economic Studies instrument. The review identified 29 publications that reported evaluations of two assays: Oncotype DX^® and MammaPrint. Studies of both tests provided evidence that their routine use was cost saving or cost-effective versus conventional approaches. Benefits were driven by optimal allocation of adjuvant chemotherapy and reduction in chemotherapy utilization. Findings were sensitive to variation in the frequency of chemotherapy prescription, chemotherapy costs, and patients’ risk profiles. Evidence suggests that multigene assays are likely cost saving or cost-effective relative to current approaches to adjuvant therapy. They should benefit decision making in early-stage breast cancer in a variety of settings worldwide.

Molecular diagnosis of antibody-mediated rejection in human kidney transplants

Antibody-mediated rejection is the major cause of kidney transplant failure, but the histology-based diagnostic system misses most cases due to its requirement for C4d positivity. We hypothesized that gene expression data could be used to test biopsies for the presence of antibody-mediated rejection. To develop a molecular test, we prospectively assigned diagnoses, including C4d-negative antibody-mediated rejection, to 403 indication biopsies from 315 patients, based on histology (microcirculation lesions) and donor-specific HLA antibody. We then used microarray data to develop classifiers that assigned antibody-mediated rejection scores to each biopsy. The transcripts distinguishing antibody-mediated rejection from other conditions were mostly expressed in endothelial cells or NK cells, or were IFNG-inducible. The scores correlated with the presence of microcirculation lesions and donor-specific antibody. Of 45 biopsies with scores>0.5, 39 had been diagnosed as antibody-mediated rejection on the basis of histology and donor-specific antibody. High scores were also associated with unanimity among pathologists that antibody-mediated rejection was present. The molecular score also strongly predicted future graft loss in Cox regression analysis. We conclude that microarray assessment of gene expression can assign a probability of ABMR to transplant biopsies without knowledge of HLA antibody status, histology, or C4d staining, and predicts future failure.

Molecular diagnosis of T cell-mediated rejection in human kidney transplant biopsies

Histologic diagnosis of T cell-mediated rejection is flawed by subjective assessments, nonspecific lesions and arbitrary rules. This study developed a molecular test for T cell-mediated rejection. We used microarray results from 403 kidney transplant biopsies to derive a classifier assigning T cell-mediated rejection scores to all biopsies, and compared these with histologic assessments. The score correlated with histologic lesions of T cell-mediated rejection (infiltrate, tubulitis). The accuracy of the classifier for the histology diagnoses was 89%. Very high and low molecular scores corresponded with unanimity among three pathologists on the presence or absence of T cell-mediated rejection, respectively. The molecular score had low sensitivity (50%) and positive predictive value (62%) for the histology diagnoses. However, histology showed similar disagreement between pathologists--only 45-56% sensitivity of one pathologist with diagnoses of T cell-mediated rejection by another. Discrepancies between molecular scores and histology were mostly when histology was ambiguous ("borderline") or unreliable, e.g. in cases with scarring or inflammation induced by tissue injury. Vasculitis (isolated v-lesion TCMR) was particularly discrepant, with most cases exhibiting low TCMR scores. We propose new rules to integrate molecular tests and histology into a precision diagnostic system that can reduce errors, ambiguity and interpathologist disagreement.

Platelet genetic biomarker quantification: comparison of fluorescent microspheres and PCR platforms

The platelet transcriptome has been extensively characterised using distinct genetic profiling platforms, with evolving evidence for differential expression patterns between healthy individuals and subject cohorts with various haematologic and cardiovascular disorders. Traditional technological platforms for platelet genetic biomarker quantification have limited applicability for clinical molecular diagnostics due to inherent complexities related to RNA isolation and analysis. We have previously established the feasibility of fluorescent microspheres as a simple and reproducible strategy for simultaneous quantification of platelet mRNAs from small volume of blood using intact platelets. We now extend these observations by formally comparing in a 50-member normal cohort the cross-platform behaviour of fluorescent microspheres to the currently accepted Q-PCR standard, using a clinically relevant 15-biomarker gene subset able to discriminate among normal and thrombocytosis cohorts. When compared to Q-PCR, genetic biomarker quantification using fluorescent microspheres demonstrated lower coefficients of variation for low-abundant transcripts, better linearity in serially diluted samples, and good overall between-platform consistency via the geometric mean regression. Neither platform demonstrated age or gender effects for any of the 15 biomarkers studied. Binding site saturation for highly abundant transcripts using fluorescent microspheres can be readily eliminated using an optimal platelet number corresponding to 0.3 ml of peripheral blood, additionally applicable to thrombocytopenic cohorts. These data provide a detailed cross-platform analysis using a relevant biomarker subset, further highlighting the applicability of fluorescent microspheres as potentially superior to Q-PCR for platelet mRNA diagnostics.

Treatment Choices Based on OncotypeDx in the Breast Oncology Care Setting

Introduction. This study aimed to evaluate whether OncotypeDx test results predict receipt of adjuvant chemotherapy in breast cancer patients who received an OncotypeDx recurrence score (RS). Materials and Methods. Pathology records were used to identify breast cancer patients who had OncotypeDx testing between December 2004 and January 2009 (n = 118). Patient sociodemographic information, tumor characteristics, RS, and treatment-specific data were collected via chart review. RS was classified as follows: low (RS ≤ 17), intermediate (RS = 18–30), or high (RS ≥ 31). Bivariate analyses were conducted to investigate the relationship between adjuvant chemotherapy receipt and each sociodemographic and clinical characteristic; significant sociodemographic and clinical variables were included in a multivariable logistic regression model. Results. In multivariable analysis controlling for tumor size, histologic grade, and nuclear grade, only RS remained significantly associated with chemotherapy uptake. Relative to low RS, an intermediate (adjusted odds ratio [AOR], 21.24; 95% confidence interval [CI], 3.62–237.52) or high (AOR, 15.07; 95% CI, 1.28–288.21) RS was associated with a greater odds of chemotherapy uptake. Discussion. Results indicate that RS was significantly associated with adjuvant chemotherapy uptake, suggesting that OncotypeDx results were used to inform treatment decision making, although it is unclear if and how the information was conveyed to patients.