To develop evidence-based guideline recommendations through a systematic review of the literature to establish standard molecular biomarker testing of colorectal cancer (CRC) tissues to guide ...epidermal growth factor receptor (EGFR) therapies and conventional chemotherapy regimens.
The American Society for Clinical Pathology, College of American Pathologists, Association for Molecular Pathology, and American Society of Clinical Oncology convened an expert panel to develop an evidence-based guideline to establish standard molecular biomarker testing and guide therapies for patients with CRC. A comprehensive literature search that included more than 4,000 articles was conducted.
Twenty-one guideline statements were established.
Evidence supports mutational testing for EGFR signaling pathway genes, since they provide clinically actionable information as negative predictors of benefit to anti-EGFR monoclonal antibody therapies for targeted therapy of CRC. Mutations in several of the biomarkers have clear prognostic value. Laboratory approaches to operationalize CRC molecular testing are presented. Key Words: Molecular diagnostics; Gastrointestinal; Histology; Genetics; Oncology.
With improved patient care, better diagnosis, and more treatment options after tumor recurrence, outcomes after fluorouracil (FU) -based treatment are expected to have improved over time in ...early-stage colon cancer. Data from 18,449 patients enrolled onto 21 phase III trials conducted from 1978 to 2002 were evaluated for potential differences in time to recurrence (TTR), time from recurrence to death (TRD), and overall survival (OS) with regard to FU-based adjuvant regimens.
Trials were predefined as old versus newer era using initial accrual before or after 1995. Outcomes were compared between patients enrolled onto old- or newer-era trials, stratified by stage.
Within the first 3 years, recurrence rates were lower in newer- versus old-era trials for patients with stage II disease, with no differences among those with stage III disease. Both TRD and OS were significantly longer in newer-era trials overall and within each stage. The lymph node (LN) ratio (ie, number of positive nodes divided by total nodes harvested) in those with stage III disease declined over time. TTR improved slightly, with larger number of LNs examined in both stages.
Improved TRD in newer trials supports the premise that more aggressive intervention (oxaliplatin- and irinotecan-based chemotherapy and/or surgery for recurrent disease) improves OS for patients previously treated in the adjuvant setting. Lower recurrence rates with identical treatments in those with stage II disease enrolled onto newer-era trials reflect stage migration over time, calling into question historical data related to the benefit of FU-based adjuvant therapy in such patients.
Personalized/individualized/tailored therapy for each patient is an important goal for improving the outcome of patients with colorectal adenocarcinoma and includes the intention to maximize efficacy ...and minimize toxicity of chemotherapeutic agents. Numerous barriers must be overcome to reach this goal because outcome is affected by an unholy trinity of tumor characteristics that include somatic alterations at the DNA, RNA, and protein level; patient characteristics that include germline genetic differences such as polymorphisms in enzymes affecting the metabolism of chemotherapeutic agents; and environmental exposures and factors that include diet and physical activity. At present, evaluation of epidermal growth factor receptor (EGFR) expression by immunohistochemistry in colorectal adenocarcinoma is generally required for treatment with one of the monoclonal antibody therapies directed against that target, despite the absence of evidence for predictive value of the assay, whereas EGFR fluorescent in situ hybridization (FISH) may be predictive. In addition, the Food and Drug Administration of the United States now requires a 'black box' warning on the packaging of irinotecan for evaluation of germline polymorphism in UGT1A1, the gene mutated in Gilbert's syndrome, for potential reduction of drug dosage in patients with the UGT1A1*28 polymorphism. Numerous other potential markers have been identified but have not yet reached levels of evidence that support their routine usage. For example, KRAS gene mutation appears to preclude improved survival after therapy with monoclonal antibody therapy directed at EGFR, and extensive DNA methylation is associated with lack of efficacy of 5-fluorouracil (5-FU)-based chemotherapy. Additional markers will come into routine usage as reports of research studies continue to appear in the literature. Clinical trials driven by molecular targets and agents directed against them, and understanding of the conflicting data on utility of markers reported in the literature, are needed to advance the field.
Over the past decade, multiple trials, including the precision medicine trial National Cancer Institute-Molecular Analysis for Therapy Choice (NCI-MATCH, EAY131, NCT02465060) have sought to determine ...if treating cancer based on specific genomic alterations is effective, irrespective of the cancer histology. Although many therapies are now approved for the treatment of cancers harboring specific genomic alterations, most patients do not respond to therapies targeting a single alteration. Further, when antitumor responses do occur, they are often not durable due to the development of drug resistance. Therefore, there is a great need to identify rational combination therapies that may be more effective. To address this need, the NCI and National Clinical Trials Network have developed NCI-ComboMATCH, the successor to NCI-MATCH. Like the original trial, NCI-ComboMATCH is a signal-seeking study. The goal of ComboMATCH is to overcome drug resistance to single-agent therapy and/or utilize novel synergies to increase efficacy by developing genomically-directed combination therapies, supported by strong preclinical in vivo evidence. Although NCI-MATCH was mainly comprised of multiple single-arm studies, NCI-ComboMATCH tests combination therapy, evaluating both combination of targeted agents as well as combinations of targeted therapy with chemotherapy. Although NCI-MATCH was histology agnostic with selected tumor exclusions, ComboMATCH has histology-specific and histology-agnostic arms. Although NCI-MATCH consisted of single-arm studies, ComboMATCH utilizes single-arm as well as randomized designs. NCI-MATCH had a separate, parallel Pediatric MATCH trial, whereas ComboMATCH will include children within the same trial. We present rationale, scientific principles, study design, and logistics supporting the ComboMATCH study.
Hereditary nonpolyposis colorectal cancer (HNPCC), also known as Lynch syndrome, is a common autosomal dominant syndrome characterized by early age at onset, neoplastic lesions, and microsatellite ...instability (MSI). Because cancers with MSI account for approximately 15% of all colorectal cancers and because of the need for a better understanding of the clinical and histologic manifestations of HNPCC, the National Cancer Institute hosted an international workshop on HNPCC in 1996, which led to the development of the Bethesda Guidelines for the identification of individuals with HNPCC who should be tested for MSI. To consider revision and improvement of the Bethesda Guidelines, another HNPCC workshop was held at the National Cancer Institute in Bethesda, MD, in 2002. In this commentary, we summarize the Workshop presentations on HNPCC and MSI testing; present the issues relating to the performance, sensitivity, and specificity of the Bethesda Guidelines; outline the revised Bethesda Guidelines for identifying individuals at risk for HNPCC; and recommend criteria for MSI testing.
Domestication is rife with episodes of interbreeding between cultured and wild populations, potentially challenging adaptive variation in the wild. In Atlantic salmon,
, the number of domesticated ...individuals far exceeds wild individuals, and escape events occur regularly, yet evidence of the magnitude and geographic scale of interbreeding resulting from individual escape events is lacking. We screened juvenile Atlantic salmon using 95 single nucleotide polymorphisms following a single, large aquaculture escape in the Northwest Atlantic and report the landscape-scale detection of hybrid and feral salmon (27.1%, 17/18 rivers). Hybrids were reproductively viable, and observed at higher frequency in smaller wild populations. Repeated annual sampling of this cohort revealed decreases in the presence of hybrid and feral offspring over time. These results link previous observations of escaped salmon in rivers with reports of population genetic change, and demonstrate the potential negative consequences of escapes from net-pen aquaculture on wild populations.
MicroRNAs are short noncoding RNAs that regulate gene expression and are over- or underexpressed in most tumors, including colorectal adenocarcinoma. MicroRNAs are potential biomarkers and ...therapeutic targets and agents, but limited information on microRNAome alterations during progression in the well-known adenoma-adenocarcinoma sequence is available to guide their usage.
We profiled 866 human microRNAs by microarray analysis in 69 matched specimens of microsatellite-stable adenocarcinomas, adjoining precursor adenomas including areas of high- and low-grade dysplasia, and nonneoplastic mucosa.
We found 230 microRNAs that were significantly differentially expressed during progression, including 19 not reported previously. Altered microRNAs clustered into two major patterns of early (type I) and late (type II) differential expression. The largest number (n = 108) was altered at the earliest step from mucosa to low-grade dysplasia (subtype IA) prior to major nuclear localization of β-catenin, including 36 microRNAs that had persistent differential expression throughout the entire sequence to adenocarcinoma. Twenty microRNAs were intermittently altered (subtype IB), and six were transiently altered (subtype IC). In contrast, 33 microRNAs were altered late in high-grade dysplasia and adenocarcinoma (subtype IIA), and 63 in adenocarcinoma only (subtype IIB). Predicted targets in 12 molecular pathways were identified for highly altered microRNAs, including the Wnt signaling pathway leading to low-grade dysplasia. β-catenin expression correlated with downregulated microRNAs.
Our findings suggest that numerous microRNAs play roles in the sequence of molecular events, especially early events, resulting in colorectal adenocarcinoma. The temporal patterns and complexity of microRNAome alterations during progression will influence the efficacy of microRNAs for clinical purposes.
Human colorectal cancer (CRC) arises from activating mutations in the Wnt/β-catenin pathway that converge with additional molecular changes to shape tumor development and patient prognosis. We report ...here that Na+/H+ exchanger 3 regulating factor 1 (NHERF1)/EBP50, an adaptor molecule that interacts with β-catenin, undergoes successive alterations during the colorectal adenoma-to-carcinoma transition, ranging from loss of normal apical membrane distribution to ectopic cytoplasmic overexpression. NHERF1 depletion in human intestinal epithelial polarized cells induced epithelial-mesenchymal transition, β-catenin nuclear translocation with elevation of Wnt/β-catenin transcriptional targets, and increased cell migration and invasion. Ectopic cytoplasmic NHERF1 expression additionally intensified the transformed phenotype by increasing cell proliferation. The epithelial morphology and reduced cell motility could only be restored by re-expression of NHERF1 specifically at the apical plasma membrane. We conclude that alterations in the apical membrane localization of NHERF1 contribute to CRC through the disruption of epithelial morphology. This study identifies NHERF1 as a new player in CRC progression and supports the notion that the expression or subcellular distribution of NHERF1 may be used as diagnostic marker for CRC.
MicroRNA (miRNA) expression profile can be used as prognostic marker for human cancers. We aim to explore the significance of miRNAs in colorectal cancer (CRC) metastasis.
We performed miRNA ...microarrays using primary CRC tissues from patients with and without metastasis, and validated selected candidates in 85 CRC samples by quantitative real-time PCR (qRT-PCR). We tested metastatic activity of selected miRNAs and identified miRNA targets by prediction algorithms, qRT-PCR, western blot and luciferase assays. Clinical outcomes were analysed in six sets of CRC cases (n=449), including The Cancer Genome Atlas (TCGA) consortium and correlated with miR-224 status. We used the Kaplan-Meier method and log-rank test to assess the difference in survival between patients with low or high levels of miR-224 expression.
MiR-224 expression increases consistently with tumour burden and microsatellite stable status, and miR-224 enhances CRC metastasis in vitro and in vivo. We identified SMAD4 as a miR-224 target and observed negative correlation (Spearman Rs=-0.44, p<0.0001) between SMAD4 and miR-224 expression in clinical samples. Patients with high miR-224 levels display shorter overall survival in multiple CRC cohorts (p=0.0259, 0.0137, 0.0207, 0.0181, 0.0331 and 0.0037, respectively), and shorter metastasis-free survival (HR 6.51, 95% CI 1.97 to 21.51, p=0.0008). In the TCGA set, combined analysis of miR-224 with SMAD4 expression enhanced correlation with survival (HR 4.12, 95% CI 1.1 to 15.41, p=0.0175).
MiR-224 promotes CRC metastasis, at least in part, through the regulation of SMAD4. MiR-224 expression in primary CRC, alone or combined with its targets, may have prognostic value for survival of patients with CRC.
The National Cancer Institute-Molecular Analysis for Therapy Choice (NCI-MATCH) trial is a national signal-finding precision medicine study that relies on genomic assays to screen and enroll patients ...with relapsed or refractory cancer after standard treatments. We report the analytical validation processes for the next-generation sequencing (NGS) assay that was tailored for regulatory compliant use in the trial. The Oncomine Cancer Panel assay and the Personal Genome Machine were used in four networked laboratories accredited for the Clinical Laboratory Improvement Amendments. Using formalin-fixed paraffin-embedded clinical specimens and cell lines, we found that the assay achieved overall sensitivity of 96.98% for 265 known mutations and 99.99% specificity. High reproducibility in detecting all reportable variants was observed, with a 99.99% mean interoperator pairwise concordance across the four laboratories. The limit of detection for each variant type was 2.8% for single-nucleotide variants, 10.5% for insertion/deletions, 6.8% for large insertion/deletions (gap ≥4 bp), and four copies for gene amplification. The assay system from biopsy collection through reporting was tested and found to be fully fit for purpose. Our results indicate that the NCI-MATCH NGS assay met the criteria for the intended clinical use and that high reproducibility of a complex NGS assay is achievable across multiple clinical laboratories. Our validation approaches can serve as a template for development and validation of other NGS assays for precision medicine.
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