Multicenter Evaluation of the Idylla NRAS-BRAF Mutation Test in Metastatic Colorectal Cancer

Current and Emerging Applications of Droplet Digital PCR in Oncology: An Updated Review

In the era of personalized medicine and targeted therapies for the management of patients with cancer, ultrasensitive detection methods for tumor genotyping, such as next-generation sequencing or droplet digital polymerase chain reaction (ddPCR), play a significant role. In the search for less invasive strategies for diagnosis, prognosis and disease monitoring, the number of publications regarding liquid biopsy approaches using ddPCR has increased substantially in recent years. There is a long list of malignancies in which ddPCR provides a reliable and accurate tool for detection of nucleic acid-based markers derived from cell-free DNA, cell-free RNA, circulating tumor cells, extracellular vesicles or exosomes when isolated from whole blood, plasma and serum, helping to anticipate tumor relapse or unveil intratumor heterogeneity and clonal evolution in response to treatment. This updated review describes recent developments in ddPCR platforms and provides a general overview about the major applications of liquid biopsy in blood, including its utility for molecular response and minimal residual disease monitoring in hematological malignancies or the therapeutic management of patients with colorectal or lung cancer, particularly for the selection and monitoring of treatment with tyrosine kinase inhibitors. Although plasma is the main source of genetic material for tumor genomic profiling, liquid biopsy by ddPCR is being investigated in a wide variety of biologic fluids, such as cerebrospinal fluid, urine, stool, ocular fluids, sputum, saliva, bronchoalveolar lavage, pleural effusion, mucin, peritoneal fluid, fine needle aspirate, bile or pancreatic juice. The present review focuses on these "alternative" sources of genetic material and their analysis by ddPCR in different kinds of cancers.

Comparison of Biocartis IDYLLA ™ cartridge assay with Qiagen GeneReader NGS for detection of targetable mutations in EGFR, KRAS/NRAS, and BRAF genes

Lung and colorectal cancers (CRC) have two of the highest mortality rates among all cancer types, and their occurrence and the need for personalized diagnostics and subsequent therapy were not influenced by the COVID-19 pandemics. However, due to the disruption of established delivery chains, standard assays for in vitro diagnostics of those cancers were temporarily not available, forcing us to implement alternative testing methods that enabled at least basic therapy decision making. For this reason, we evaluated rapid testing on the Biocartis Idylla™ platform (Biocartis, Mechelen, Belgium) for four important genes commonly mutated in lung and colorectal cancers, namely EGFR, NRAS, KRAS, and BRAF. Clinical specimens from which the mutation status has previously been determined using Next Generation Sequencing (NGS), were retested to determine whether Idylla™ can offer accurate results. To compare the results, the sensitivity, specificity, positive predictive values (PPV) and negative predictive values (NPV) are calculated for each of the mutation types and then combined to determine the values of the Idylla™ system in total, while setting NGS as the gold-standard basis the assays were compared with. Idylla testing thereby displayed acceptable sensitivity and specificity and delivered reliable results for initial therapy decisions.

BRAF: A Two-Faced Janus

Gain-of-function of V-Raf Murine Sarcoma Viral Oncogene Homolog B (BRAF) is one of the most frequent oncogenic mutations in numerous cancers, including thyroid papillary carcinoma, melanoma, colon, and lung carcinomas, and to a lesser extent, ovarian and glioblastoma multiforme. This mutation aberrantly activates the mitogen-activated protein (MAP) kinase extracellular signal-regulated kinase (MEK)/extracellular signal-regulated kinase (ERK) signaling pathway, thereby eliciting metastatic processes. The relevance of BRAF mutations stems from its prognostic value and, equally important, from its relevant therapeutic utility as an actionable target for personalized treatment. Here, we discuss the double facets of BRAF. In particular, we argue the need to implement diagnostic molecular algorithms that are able to detect this biomarker in order to streamline and refine diagnostic and therapeutic decisions.

[Update of the recommendations for the determination of biomarkers in colorectal carcinoma. National Consensus of the Spanish Society of Medical Oncology and the Spanish Society of Pathology]

This update of the consensus of the Spanish Society of Medical Oncology (Sociedad Española de Oncología Médica - SEOM) and the Spanish Society of Pathology (Sociedad Española de Anatomía Patológica - SEAP), reviews the advances in the analysis of biomarkers in advanced colorectal cancer (CRC) as well as susceptibility markers of hereditary CRC and molecular biomarkers of localized CRC. Recently published information on the essential determination of KRAS, NRAS and BRAF mutations and the possible benefits of determining the amplification of human epidermal growth factor receptor 2 (HER2), the expression of proteins in the DNA repair pathway and the study of NTRK fusions are also evaluated. From a pathological point of view, the importance of analysing the tumour budding and poorly differentiated clusters and its prognostic value in CRC is reviewed, as well as the impact of molecular lymph node analysis on lymph node staging in CRC. The incorporation of pan-genomic technologies, such as next-generation sequencing (NGS) and liquid biopsy in the clinical management of patients with CRC is also outlined. All these aspects are developed in this guide which, like the previous one, will be revised when necessary in the future.

Ultrarapid EGFR Mutation Screening Followed by Comprehensive Next-Generation Sequencing: A Feasible, Informative Approach for Lung Carcinoma Cytology Specimens With a High Success Rate

INTRODUCTION

For patients with advanced NSCLC, cytologic samples may be the only diagnostic specimen available for molecular profiling. Although both rapid and comprehensive assessment are essential in this setting, an integrated multitest approach remains an important strategy in many laboratories, despite the risks and challenges when working with scant samples. In this study, we describe our experience and high success rate in using a multitest approach, focusing on the clinical validation and incorporation of ultrarapid EGFR testing using the Idylla system followed by comprehensive next-generation sequencing (NGS).

METHODS

Cytology samples received for routine molecular testing were included in this study. The performance characteristics of the EGFR Idylla assay were assessed; tissue suitability parameters and interpretation criteria to supplement automated mutation calling were established. The assay performance was monitored for 1 year, comparing the results with those of concurrent NGS testing by MSK-IMPACT (primarily) or MSK-AmpliSeq and MSK-Fusion solid panel in a subset of cases.

RESULTS

Overall, 301 samples were studied; 83 samples were included in validation (60.2% [50 of 83] were positive for EGFR mutations). Concordance with the reference method was 96.4% (80 of 83) of the samples with excellent reproducibility. The limit of detection was variable depending on the total tissue input and the specific mutation tested. Unextracted tissue inputs that maintained total EGFR cycle of quantification at less than 23 allowed all mutations to be detected if present at greater than 5% variant allele frequency. Mutations could be detected at 1% variant allele frequency with total EGFR cycle of quantification of 18. During the clinical implementation phase, 218 NSCLC samples were tested by Idylla (24.3% [53 of 218] were EGFR mutation positive). Concurrent NGS testing was requested on 165 samples and successfully performed on 96.4% (159 of 165) of the samples. The Idylla automated results were concordant with those obtained by NGS in 96.2% (153 of 159) of cases and improved to 98.7% (157 of 159) after incorporation of manual review criteria to supplement automated calling, resulting in a diagnostic sensitivity of 95.6% (95% confidence interval: 84.9%-99.5%). In general, 9% (14 of 159) of the cases tested by NGS had EGFR mutations not covered by the Idylla assay, primarily insertions in exon 19 and 20 and minor mutations cooccurring with canonical sensitizing mutations.

CONCLUSIONS

Comprehensive molecular testing is feasible and has a high success rate in NSCLC cytology samples when using a multitest approach. Testing with the Idylla system enables rapid and accurate determination of the EGFR status without compromising subsequent NGS testing.

KRAS, NRAS, and BRAF mutation prevalence, clinicopathological association, and their application in a predictive model in Mexican patients with metastatic colorectal cancer: A retrospective cohort study

Mutations in KRAS, NRAS, and BRAF (RAS/BRAF) genes are the main predictive biomarkers for the response to anti-EGFR monoclonal antibodies (MAbs) targeted therapy in metastatic colorectal cancer (mCRC). This retrospective study aimed to report the mutational status prevalence of these genes, explore their possible associations with clinicopathological features, and build and validate a predictive model. To achieve these objectives, 500 mCRC Mexican patients were screened for clinically relevant mutations in RAS/BRAF genes. Fifty-two percent of these specimens harbored clinically relevant mutations in at least one screened gene. Among these, 86% had a mutation in KRAS, 7% in NRAS, 6% in BRAF, and 2% in both NRAS and BRAF. Only tumor location in the proximal colon exhibited a significant correlation with KRAS and BRAF mutational status (p-value = 0.0414 and 0.0065, respectively). Further t-SNE analyses were made to 191 specimens to reveal patterns among patients with clinical parameters and KRAS mutational status. Then, directed by the results from classical statistical tests and t-SNE analysis, neural network models utilized entity embeddings to learn patterns and build predictive models using a minimal number of trainable parameters. This study could be the first step in the prediction for RAS/BRAF mutational status from tumoral features and could lead the way to a more detailed and more diverse dataset that could benefit from machine learning methods.

BRAF and KRAS mutations in metastatic colorectal cancer: future perspectives for personalized therapy

Colorectal cancer (CRC) is one of the most commonly diagnosed cancers worldwide and 30% of patients with CRC experience metastasis. Patients with metastatic colorectal cancer (mCRC) have a 5-year overall survival rate of <10%. V-raf murine sarcoma viral oncogene homolog B1 (BRAF) and V-Ki-ras2 Kirsten ratsarcoma viral oncogene homolog (KRAS) mutations are mostly studied in mCRC, as clinical trials found that first-line chemotherapy with anti-epidermal growth factor receptor agent confers limited efficacy for mCRC. Treatment decisions for early-stage mCRC do not consider BRAF or KRAS mutations, given the dramatically poor prognosis conferred by these mutations in clinical trials. Thus, it is necessary to identify patients with mCRC harboring BRAF or KRAS mutations to formulate rational therapeutic strategies to improve prognosis and survival. BRAF and KRAS mutations occur in ∼10% and ∼44% of patients with mCRC, respectively. Although the survival rate of patients with mCRC has improved in recent years, the response and prognosis of patients with the aforementioned mutations are still poor. There is a substantial unmet need for prospective personalized therapies for patients with BRAF- or KRAS-mutant mCRC. In this review, we focus on BRAF and KRAS mutations to understand the mechanisms underlying resistance and improving the response rate, outcomes, and prognosis of patients with mCRC bearing these mutations and to discuss prospective personalized therapies for BRAF- and KRAS-mutant mCRC.

Update of the recommendations for the determination of biomarkers in colorectal carcinoma: National Consensus of the Spanish Society of Medical Oncology and the Spanish Society of Pathology

In this update of the consensus of the Spanish Society of Medical Oncology (Sociedad Española de Oncología Médica—SEOM) and the Spanish Society of Pathology (Sociedad Española de Anatomía Patológica—SEAP), advances in the analysis of biomarkers in advanced colorectal cancer (CRC) as well as susceptibility markers of hereditary CRC and molecular biomarkers of localized CRC are reviewed. Recently published information on the essential determination of KRAS, NRAS and BRAF mutations and the convenience of determining the amplification of human epidermal growth factor receptor 2 (HER2), the expression of proteins in the DNA repair pathway and the study of NTRK fusions are also evaluated. From the pathological point of view, the importance of analysing the tumour budding and poorly differentiated clusters, and its prognostic value in CRC is reviewed, as well as the impact of molecular lymph node analysis on lymph node staging in CRC. The incorporation of pan-genomic technologies, such as next-generation sequencing (NGS) and liquid biopsy in the clinical management of patients with CRC is also outlined. All these aspects are developed in this guide, which, like the previous one, will remain open to any necessary revision in the future.

Evaluation of KRAS, NRAS and BRAF mutational status and microsatellite instability in early colorectal carcinomas invading the submucosa (pT1): towards an in-house molecular prognostication for pathologists?

AIM

We aimed to study the prognostic value of KRAS, NRAS, BRAF mutations and microsatellite stable (MSS)/instable (MSI) in the field of colorectal cancer invading the submucosa (ie, pT1 colorectal cancer (CRC)).

METHODS

We led a case-control study in tumour samples from 60 patients with pT1 CRC with (20 cases) and without (40 cases) metastatic evolution (5 years of follow-up) which were analysed for KRAS, NRAS, BRAF mutations (Idylla testing and next generation sequencing, NGS) and MSS/MSI status (Idylla testing and expression of mismatch repair (MMR) proteins using immunohistochemistry).

RESULTS

KRAS mutations were encountered in 11/20 (55%) cases and 21/40 (52.5%) controls (OR=1.11 (0.38 to 3.25), p=0.8548), NRAS mutations in 1/20 (5%) cases and 3/40 (7.5%) controls (OR=3.08 (0.62 to 15.39), p=0.1698) and BRAF mutations in 3/20 (15%) cases and 6/40 (15%) controls (OR=1.00 (0.22 to 4.5), p=1.00). A MSI status was diagnosed in 3/20 (15%) cases and 5/40 (12.5%) controls (OR=1.2353 (0.26 to 5.79), p=0.7885). Beyond the absence of significant association between the metastatic evolution and any of the studied molecular parameters, we observed a very good agreement between methods analysing KRAS, NRAS and BRAF mutations (Kappa value of 0.849 (0.748 to 0.95) between Idylla and NGS) and MSS/MSI (Idylla)-proficient MMR/deficient MMR (immunohistochemistry) status (Kappa value of 1.00).

CONCLUSION

Although being feasible using the fully automated Idylla method as well as NGS, the molecular testing of KRAS, NRAS, BRAF and MSS/MSI status does not seem useful for prognostic purpose in the field of pT1 CRC.

Rapid On-site Molecular Evaluation in thyroid cytopathology: A same-day cytological and molecular diagnosis

BACKGROUND

Thyroid fine-needle aspirates (FNAs) with undetermined morphology can be outsourced to centralized laboratories for comprehensive molecular profiling. When a local, rapid screening rules out easily detectable BRAF and NRAS mutations outsourcing is minimized, leading to cost savings. The fully automated Idylla technology, that does not require trained staff, is an emerging option. However, Idylla platform has only been validated to process formalin fixed paraffin embedded (FFPE) sections. Here we investigate whether also the FNA needle rinse could be genotyped by the same cytopathologist who performs the FNA, a procedure that can be termed rapid on site molecular evaluation (ROME).

METHODS

To validate this approach, the Idylla BRAF and NRAS Test was performed on the rinses from 25 simulated (bench-top) FNAs, in a first part of the study. Genotyping data were compared with those obtained on matched histological FFPE blocks. The second part of the study was carried out on 25 prospectively collected routine FNAs to assess the performance of the Idylla BRAF and NRAS assay against a gold standard real time polymerase chain reaction method.

RESULTS

Idylla NRAS-BRAF Mutation Test was performed on needle rinse as well as histological FFPE blocks. A sensitivity of 88.9%, a specificity of 100.0% were obtained comparing the Idylla NRAS-BRAF Mutation Test on needle rinse to the reference method.

CONCLUSIONS

The FNA needle rinse can be directly genotyped. This obviates the need of cell block preparation, making possible a rapid combined morphological and molecular evaluation. Since DNA extraction is no longer necessary, the cytopathologist can perform ROME him/herself.

Molecular Pathology of Colorectal Cancer

Colorectal cancer (CRC) is the third most commonly diagnosed cancer. This review gives an overview of the current knowledge of molecular mechanisms of colorectal carcinogenesis and the role of molecular testing in the management of CRC. The majority of CRCs arise from precursor lesions such as adenoma, transforming to adenocarcinoma. Three molecular carcinogenesis pathways have been identified; (1) chromosomal instability, (2) microsatellite instability (MSI), and (3) CpG island methylator phenotype, each account for ~85%, 15%, and 17%, respectively. Evaluation of MSI status, extended RAS mutation analysis, and BRAF mutation analysis are recommended by the guideline published by joint effort from professional societies. MSI testing is important for identification of Lynch syndrome patients and prognostic and predictive markers. Extended RAS testing is an important predictive marker for antiepidermal growth factor receptor therapy. BRAF p.V600 mutation status can be used as prognostic marker, but not predictive marker for antiepidermal growth factor receptor therapies. Emerging technologies utilizing high throughput sequencing have introduced novel biomarkers and testing strategies. Tumor mutation burden predicts immunotherapy response in addition to MSI status. Liquid biopsy can be utilized when adequate tissue sample is not available or for monitoring therapy response. However, assay standardization and guidelines and recommendations for utilization of these assay will be needed. The advancement in CRC research and technologies will allow better prognostication and therapy stratification for the management of patients with CRCs.

Impact of RAS/RAF mutations on clinical and prognostic outcomes in metastatic colorectal cancer

Introduction: Early-activated RAS/RAF mutation status is a key molecular finding in colorectal cancer (CRC), while these mutations have been proposed as predictive and prognostic biomarkers. The present study has been designed as a longitudinal study to evaluate and summarize the different genotypes of metastatic CRC (mCRC), and assessing any association with the disease prognosis and clinicopathological characteristics. This study was performed in two main referral hospitals of Tabriz University of Medical Sciences, over three years (2016-2018).

Methods: Mutations were detected by Idylla tests of KRAS/NRAS/BRAF among a total of 173 mCRCs, using surgically-resected specimens or biopsied samples. To evaluate the factors associated with overall survival (OS) and prognosis, the Cox proportional hazards model was used in two steps to estimate the outcome measures (hazard ratio, or HR) with a 95% confidence interval (CI).

Results: The nominal 1 to 5-year OS rates were 78%, 65%, 55%, 46%, and 42%, respectively. KRAS mutations in codon 12 was an independent significant prognostic factor, as the patients with codon 12 mutations had a significantly lower OS (P Log-rank=0.049) and a higher hazard of mortality (HR=2.30; 95% CI: 0.95-5.58; P =0.066). Also, the mCRC patients with liver metastasis (HR=2.49; 95% CI: 1.49-12.52; P =0.002) and tumors of the distal colon (HR=3.36; 95% CI: 1.07-10.49; P =0.037) had a significantly worse prognosis.

Conclusion: KRAS mutation in codon 12 was an independent significant poor prognostic factor, and patients with liver metastasis had a significantly worse prognosis. Routinely performing specific oncogenic tests may help improve the patients’ prognosis and life expectancy.

Prospective evaluation of two screening methods for molecular testing of metastatic melanoma: Diagnostic performance of BRAF V600E immunohistochemistry and of a NRAS-BRAF fully automated real-time PCR-based assay

Screening for theranostic biomarkers is mandatory for the therapeutic management of cutaneous melanoma. BRAF and NRAS genes must be tested in routine clinical practice. The methods used to identify these alterations must be sensitive to detect mutant alleles in a background of wild type alleles, and specific to identify the correct mutation. They should not require too much material, since in some cases the available samples are small biopsies. Finally, they should also be quick enough to allow a rapid therapeutic management of patients. Sixty five consecutive formalin-fixed paraffin-embedded (FFPE) melanoma samples were prospectively tested for BRAF mutations with the VE1 (anti-BRAF V600E) antibody and for both BRAF and NRAS mutations with the Idylla NRAS-BRAF-EGFR S492R Mutation Assay cartridges. Results were compared to our routine laboratory practice, allele specific amplification and/or Sanger sequencing and discordant cases confirmed by digital PCR. Excluding discordant by-design-mutations, system failures and DNA quantity or quality failures, BRAF IHC demonstrated an overall concordance of 89% for BRAF V600E mutation detection, the Idylla system gave a concordance of 100% for BRAF mutation detection and of 92.1% for NRAS mutation detection when compared to our reference. When discrepancies were observed, all routine results were confirmed by digital PCR. Finally, BRAF IHC positive predictive value (PPV) was of 82% and negative predictive value (NPV) of 92%. The Idylla cartridges showed a PPV and NPV of both 100% for BRAF mutation detection and a PPV and NPV of 100% and 87% respectively, for NRAS mutation detection. In conclusion, BRAF V600E immunohistochemistry is efficient for detecting the V600E mutation, but negative cases should be further evaluated by molecular approaches for other BRAF mutations. Since 3 NRAS mutations have not been detected by the Idylla NRAS-BRAF-EGFR S492R Mutation Assay, these cartridges should not be used as a substitute for traditional molecular methods in the conventional patient therapeutic care process without the expertise needed to have a critical view of the produced results.

Rapid clinical mutational testing of KRAS, BRAF and EGFR: a prospective comparative analysis of the Idylla technique with high-throughput next-generation sequencing

AIMS

Precision medicine therapy is remodelling the diagnostic landscape of cancer. The success of these new therapies is often based on the presence or absence of a specific mutation in a tumour. The Idylla platform is designed to determine the mutational status of a tumour as quickly and accurately as possible, as a rapid, accurate diagnosis is of the utmost importance for the treatment of patients. This is the first complete prospective study to investigate the robustness of the Idylla platform for EGFR, KRAS and BRAF mutations in non-small cell lung cancer, metastatic colorectal cancer and metastatic melanoma, respectively.

METHODS

We compared prospectively the Idylla platform with the results we obtained from parallel high-throughput next-generation sequencing, which is the current gold standard for mutational testing. Furthermore, we evaluated the benefits and disadvantages of the Idylla platform in clinical practice. Additionally, we reviewed all the published Idylla performance articles.

RESULTS

There was an overall agreement of 100%, 94% and 94% between the next-generation panel and the Idylla BRAF, KRAS and EGFR mutation test. Two interesting discordant findings among 48 cases were observed and will be discussed together with the advantages and shortcoming of both techniques.

CONCLUSION

Our observations demonstrate that the Idylla cartridge for the EGFR, KRAS and BRAF mutations is highly accurate, rapid and has a limited hands-on time compared with next-generation sequencing.

Evaluation of a Fully Automated Idylla Test System for Microsatellite Instability in Colorectal Cancer

BACKGROUND

Microsatellite instability (MSI) is a phenotype commonly observed in colorectal cancer, and is caused by a deficient mismatch repair system. Determining MSI status greatly aids tumor prognosis and treatment plans in colorectal cancer, and plays a critical role in recent United States Food and Drug Administration-approved immunotherapies. As recognition of its importance grows, MSI has been identified in more types of cancers, underscoring the importance of accurate assays for determining MSI status in tumor cells. Currently, tumor MSI status is detected via polymerase chain reaction-based methods or immunohistochemistry.

MATERIALS AND METHODS

In this study, we tested a new, fully automated MSI detection system (Idylla MSI detection kit) released by Biocartis. We evaluated 42 formalin-fixed paraffin-embedded tumor tissues, which were clinically tested for MSI status using the polymerase chain reaction or immunohistochemistry method, with the Idylla MSI detection system.

RESULTS

The Idylla MSI detection system showed an overall 97.62% concordance rate with previously used methods. Moreover, this fully automated system requires less than 5 minutes "hands on" preparation time and 150 minutes total run time per sample.

CONCLUSION

The Biocartis Idylla MSI kit proves a powerful tool to accurately detect MSI status in tumor cells in a rapid and almost labor-free manner.

Downregulation of SPTAN1 is related to MLH1 deficiency and metastasis in colorectal cancer

Introduction

Colorectal cancers (CRCs) deficient in the DNA mismatch repair protein MutL homolog 1 (MLH1) display distinct clinicopathological features and require a different therapeutic approach compared to CRCs with MLH1 proficiency. However, the molecular basis of this fundamental difference remains elusive. Here, we report that MLH1-deficient CRCs exhibit reduced levels of the cytoskeletal scaffolding protein non-erythroid spectrin αII (SPTAN1), and that tumor progression and metastasis of CRCs correlate with SPTAN1 levels.

Methods and results

To investigate the link between MLH1 and SPTAN1 in cancer progression, a cohort of 189 patients with CRC was analyzed by immunohistochemistry. Compared with the surrounding normal mucosa, SPTAN1 expression was reduced in MLH1-deficient CRCs, whereas MLH1-proficient CRCs showed a significant upregulation of SPTAN1. Overall, we identified a strong correlation between MLH1 status and SPTAN1 expression. When comparing TNM classification and SPTAN1 levels, we found higher SPTAN1 levels in stage I CRCs, while stages II to IV showed a gradual reduction of SPTAN1 expression. In addition, SPTAN1 expression was lower in metastatic compared with non-metastatic CRCs. Knockdown of SPTAN1 in CRC cell lines demonstrated decreased cell viability, impaired cellular mobility and reduced cell-cell contact formation, indicating that SPTAN1 plays an important role in cell growth and cell attachment. The observed weakened cell-cell contact of SPTAN1 knockdown cells might indicate that tumor cells expressing low levels of SPTAN1 detach from their primary tumor and metastasize more easily.

Conclusion

Taken together, we demonstrate that MLH1 deficiency, low SPTAN1 expression, and tumor progression and metastasis are in close relation. We conclude that SPTAN1 is a candidate molecule explaining the tumor progression and metastasis of MLH1-deficient CRCs. The detailed analysis of SPTAN1 is now mandatory to substantiate its relevance and its potential value as a candidate protein for targeted therapy, and as a predictive marker of cancer aggressiveness.