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FDA approves blood-based colorectal screen

Posted in Biomarkers & Medical Diagnostics, Gastroenterology, Genetics & Innovations in Treatment, Genetics & Pharmaceutical, Genome Biology, Genomic Testing: Methodology for Diagnosis, Proteins, Proteomics, tagged biomarker/companion diagnostics, Blood test, Cancer screening, Colorectal cancer, septin 9 on April 21, 2016| Leave a Comment »

FDA approves blood-based colorectal screen

Larry H. Bernstein, MD, FCAP, Curator

LPBI

FDA Clears First Blood-Based Colorectal Cancer Screening Test.
Lab Soft News by Bruce Friedman
https://www.linkedin.com/pulse/fda-clears-first-blood-based-colorectal-cancer-screening-joseph-colao

In the upcoming months, there surely will be an increasing number of blood-based genomic cancer tests approved by the FDA. This specific test market is just too attractive. In a recent note, I discussed some of these testing initiatives from the perspective of companion diagnostics (see: An Expanding Definition for Companion Diagnostics). This form of testing in used in collaboration with cancer therapy to select the right drug or monitor the effectiveness of drug therapy. Obviously and of equal importance are biomarkers intended for cancer screening. A recent article reported that the FDA has cleared the first blood-based screening test for colorectal cancer (see: FDA Clears First Blood-Based Colorectal Cancer Screening Test), Below is an excerpt from it:

The first blood-based colorectal cancer (CRC) screening test, Epi proColon...has been approved by the US Food and Drug Administration (FDA)….The Epi proColon test is a qualitative in vitro diagnostic test for detecting methylated Septin9 DNA, which has been associated with the occurrence of CRC, in plasma obtained from whole-blood specimens. It is indicated for use in average-risk patients who have chosen not to undergo other screening methods, such as colonoscopy or stool-based tests.The test was recommended for FDA approval in 2014 by the Molecular and Clinical Genetics Panel of the FDA’s Medical Devices Advisory Committee, but some of the experts were not convinced….The agency approved the Epi proColon test for CRC screening in average-risk patients (as defined by current screening guidelines) who choose not to be screened by colonoscopy or a stool-based FIT [fecal immunochemical test for occult blood in the stool].The Epi proColon blood test for CRC screening can be performed during routine office visits. It requires no dietary restrictions or alterations in medication use. The blood sample is analyzed by a local or regional diagnostic laboratory….The company will initiate a postapproval study to show the long-term benefit of blood-based CRC screening using Epi proColon, as required by the FDA.

Here’s more information about Septin9 DNA (see: Plasma methylated septin 9: a colorectal cancer screening marker):

The biomarker septin 9 has been found to be hypermethylated in nearly 100% of tissue neoplasia specimens and detected in circulating DNA fractions of CRC patients. A commercially available assay for septin 9 has been developed with moderate sensitivity (∼70%) and specificity (∼90%) and a second generation assay, Epi proColon 2.0 (Epigenomics AG), shows increased sensitivity (∼92%).The performance of the assay proved to be independent of tumor site and reaches a high sensitivity of 77%, even in early cancer stages (I and II). Furthermore, septin 9 was recently used in follow-up studies for detection of early recurrence of CRC.

There is clearly a need for a blood-based biomarker for colorectal cancer screening. Patients tend to dislike the home stool collection that is required for fecal immunochemical tests for occult blood in the stool (FIT). Moreover, testing for blood in the stool offers a somewhat crude substitute for the identification of reliable cancer biomarkers in the blood. It must be noted, however, that some of the FDA experts in 2014 were not convinced that the septic 9 biomarker offered advantages over FIT.

I am not sure that septin 9 will be the final and most efficient biomarker for CRC but I am sure of two things. The first is that there will eventually be a high-specificity, high-sensitivity blood test for CRC. The second is that probably tens of billions of dollars would be saved by the elimination of screening colonoscopies for CRC by such a test. I found an article dating way back to 2002 about the number of screening endoscopies performed in the U.S. but the numbers are sill impressive (see: How many endoscopies are performed for colorectal cancer screening?) Here is a quote from it: “Approximately 2.8 million flexible sigmoidoscopes and 14.2 million colonoscopies were estimated to have been performed in 2002.” Needless to say, many gastroenterologists and radiologists may be hoping that such a lab test does not reach the market soon.

Septin-9 is a protein that in humans is encoded by the SEPT9 gene.^[1]^[2]^[3

SEPT9 has been shown to interact with SEPT2^[4] and SEPT7.^[4]

Along with AHNAK, eIF4E and S100A11, SEPT9 has been shown to be essential for pseudopod protrusion, tumor cell migration and invasion.^[5]

The v2 region of the SEPT9 promoter has been shown to be methylated in colorectal cancer tissue compared with normal colonic mucosa.^[6] Using highly sensitive real time PCR assays, methylated SEPT9 was detected in the blood of colorectal cancer patients. This alternate methylation pattern in cancer samples is suggestive of an aberrant activation or repression of the gene compared to normal tissue samples.^[7]^[8]

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In focus: Circulating Tumor Cells

Posted in Bio Instrumentation in Experimental Life Sciences Research, Biological Networks, Gene Regulation and Evolution, Biomarkers & Medical Diagnostics, Biomedical Measurement Science, CANCER BIOLOGY & Innovations in Cancer Therapy, FDA Regulatory Affairs, Medical Devices R&D Investment, tagged biomarkers, Blood test, breast cancer, CD44, CD47, CellSearch System, Circulating tumor cell, colon cancer, CTC, EPCAM, esophageal cancer, FDA, immunomagnetic, Key words: circulating tumor cells, Martin Fleisher, metastasis, metastasis initiating cells, MIC, overall survival, progression-free survival, Prostate cancer, Targeted therapy, tumor microenvironment, University of Texas MD Anderson Cancer Center, Veridex LLC, xenograft on June 24, 2013| 4 Comments »

Author/Curator: Ritu Saxena, PhD

Word Cloud By Danielle Smolyar

For several decades, research efforts have focused on targeting progression of cancer cells in primary tumors. Primary tumor cell targeting strategies include standard chemotherapy and immunotherapy and modulation of host microenvironment including tumor vasculature. However, cancer progression is comprised of both primary tumor growth and secondary metastasis (Langley RR and Fidler IJ. Tumor cell-organ microenvironment interactions in the pathogenesis of cancer metastasis. Endocr Rev. 2007 May;28(3):297-321; http://www.ncbi.nlm.nih.gov/pubmed/17409287). Owing to the property of unilimited cell division, cells in primary tumor increase rapidly in number and density and are able to favorably influence their microenvironment. Metastasis, on the other hand, depends on the ability of cancer cells to disseminate, circulate, adapt to the harsh environment and seed in different organs to establish secondary tumors. Although tumor cells are shed into the circulation in large numbers since early stages of tumor formation, few tumor cells can survive and proceed to overt metastasis. (Husemann Y et al. Systemic spread is an early step in breast cancer. Cancer Cell. 2008 Jan;13(1):58-68; http://www.ncbi.nlm.nih.gov/pubmed/18167340). Tight vascular wall barriers, unfavorable conditions for survival in distant organs, and a rate-limiting acquisition of organ colonization functions are just some of the impediments to the formation of distant metastasis (Chiang AC and Massagué J. Molecular basis of metastasis. N Engl J Med. 2008 Dec 25;359(26):2814-23; http://www.ncbi.nlm.nih.gov/pubmed/19109576).

It has been hypothesized that metastasis is initiated by a subpopulation of circulating tumor cells (CTC) found in the blood of patients. Therefore, understanding the function of CTC and targeting the CTC is gaining attention as a possible therapeutic avenue in carcinoma treatment.

Figure: Circulating tumor cells in the metastatic cascade

(Image source: Chaffer CL and Weinberg RA. Science 2011,331, pp. 1559-1564; http://www.ncbi.nlm.nih.gov/pubmed/21436443)

Isolation of CTC

Initial methods relied on the difference in physical properties of cells. When spun in a centrifuge, different cells in the blood sample settle in separate layers based on their byoyancy, and CTC are found in the white blood cell fraction. Because CTC are generally larger than white blood cells, a size-based filter could be used to separate the cell types (Vona G, et al, Isolation by size of epithelial tumor cells : a new method for the immunomorphological and molecular characterization of circulating tumor cells. Am J Pathol, 2000 Jan;156(1):57-63; http://www.ncbi.nlm.nih.gov/pubmed/10623654).

Herbert A Fritsche, PhD, Professor and Chief, Clinical Chemistry, Department of Laboratory Medicine, The University of Texas, MD Anderson Cancer Center, demonstrated that the CTC can be captured using antibody labeled magnetic beads, either in positive or negative selection schema. After the circulating tumor cells are isolated, they may be characterized by immunohistochemistry and counted. Alternatively, these cells may be characterized by gene expression analysis using RT-PCR. One of the CTC detection methods, Veridex Inc, Cell Search Assay, has been cleared by the US FDA for use as a prognostic test in patients with metastatic cancers of the breast, prostate and colon. This technology relies on the expression of epithelial cellular adhesion molecular (EpCAM) by epithelial cells and the isolation of these cells by immunomagnetic capture using anti-EpCAM antibodies. Enriched CTC are identified by immunofluorescence. Martin Fleisher, PhD, Chair, Department of Clinical Laboratories, Memorial Sloan-Kettering Cancer Center discussed in a webinar at the biomarker symposia, Cambridge Healthtech Institute, that every new technology has shortcomings, and the reliance on cancer cells to express sufficient EpCAM to enable capture may affect the role of this technology in future clinical use. Heterogeneous downregulation of epithelial surface antigen in invasive tumor cells has been reported. Thus, alternative methods to detect CTC are being developed. These new methods include-

Flow cytometry that sorts cells by size and surface antigen expression.
CTC microchips that are designed to capture CTC as whole blood flows past EpCAM-coated mirco-posts.
Enrichment by filtration using filters with a pore size of 7-8 µm, that permits smaller red blood cell, leukocytes, and platelets to pass, but captures CTC that have diameters of about 12-15 µm.

Better identification of CTC

Baccelli et al (2013) developed a xenograft assay and demonstrated that the primary human luminal breast cancer CTC contain metastasis-initiated cells (MICs) that give rise to bone, lung and liver metastases in mice. These MIC-containing CTC populations expressed EPCAM, CD44, CD47 and MET. It was observed that in a small cohort of patients with metastases, the number of CTC expressing markers EPCAM,CD44, CD47 and MET, but not of bulk EPCAM+ CTC, correlated with lower overall survival and increased number of metastasic sites. These data describe functional circulating MICs and associated markers, which may aid the design of better tools to diagnose and treat metastatic breast cancer. The findings were published in the Nature Biotechnology journal recently (Baccelli I, et al. Identification of a population of blood circulating tumor cells from breast cancer patients that initiates metastasis in a xenograft assay. Nature Biotechnology 2013 31, 539–544; http://www.ncbi.nlm.nih.gov/pubmed/23609047).

CTC as prognostic and predictive factor for cancer progression

Martin Fleisher, PhD states “detecting CTC in peripheral blood of patients with cancer has become a clinically relevant and important prognostic biomarker and has been shown to be a predictive biomarker post-therapy. But, key to the use of CTC as a biomarker is the technology designed to enrich cancer cells from peripheral blood.”

Since CTC isolation methods started being established, correlation studies between the cells and a patient’s disease emerged. In 2004, investigators at the Department of Breast Medical Oncology, University of Texas MD Anderson Cancer Center (Houston, TX) discovered that the CTC were associated with disease progression and survival in metastatic breast cancer. The clinical trial recruited 177 patients with measurable metastatic breast cancer for levels of CTC both before the patients were to start a new line of treatment and at the first follow-up visit. The progression of the disease or the response to treatment was determined with the use of standard imaging studies at the participating centers. Patients in a training set with levels of CTC equal to or higher than 5 per 7.5 ml of whole blood, as compared with the group with fewer than 5 CTC per 7.5 ml, had a shorter median progression-free survival (2.7 months vs. 7.0 months, P<0.001) and shorter overall survival (10.1 months vs. >18 months, P<0.001). At the first follow-up visit after the initiation of therapy, this difference between the groups persisted (progression-free survival, 2.1 months vs. 7.0 months; P<0.001; overall survival, 8.2 months vs. >18 months; P<0.001), and the reduced proportion of patients (from 49 percent to 30 percent) in the group with an unfavorable prognosis suggested that there was a benefit from therapy. Thus, the number of CTC was found to be an independent predictor of progression-free survival and overall survival in patients with metastatic breast cancer (Cristofanilli M, et al, Circulating tumor cells, disease progression, and survival in metastatic breast cancer. N Engl J Med. 2004 Aug 19;351(8):781-91; http://www.ncbi.nlm.nih.gov/pubmed/15317891).

Similar results have been observed in other cancer types, including prostate and colorectal cancer. The Cell Search System developed by Veridex LLC (Huntingdon Valley, PA) enumerated CTC from 7.5 mL of venous blood and was used to compare the outcomes from three prospective multicenter studies investigating the use of CTC to monitor patients undergoing treatment for metastatic breast, colorectal, or prostate cancer. Evaluation of CTC at anytime during the course of disease allowed assessment of patient prognosis and is predictive of overall survival (Miller MC, et al. Significance of Circulating Tumor Cells Detected by the CellSearch System in Patients with Metastatic Breast Colorectal and Prostate Cancer. J Oncol. 2010; http://www.ncbi.nlm.nih.gov/pubmed/20016752). In addition, the CTC test may permit the oncologist to make an early decision to discontinue first line therapy for metastatic breast cancer and pursue more aggressive alternative treatments.

Genetic analysis of CTC

Additional studies have analyzed the genetic mutations that the cells carry, comparing the mutations to those in a primary tumor or correlating the findings to a patient’s disease severity or spread. In one study, lung cancer patients whose CTC carried a mutation known to cause drug resistance had faster disease progression than those whose CTC lacked the mutation. The investigators analyzed the evolutionary aspect of cancer progression and studied the precursor cells of metastases directly for the identification of prognostic and therapeutic markers. Single disseminated cancer cells isolated from lymph nodes and bone marrow of 107 consecutive esophageal cancer patients were analyzed by whole-genome screening which revealed that primary tumors and lymphatically and hematogenously disseminated cancer cells diverged for most genetic aberrations. Chromosome 17q12-21, the region comprising HER2, was identified as the most frequent gain in disseminated tumor cells that were isolated from both ectopic sites. Furthermore, survival analysis demonstrated that HER2 gain in a single disseminated tumor cell but not in primary tumors conferred high risk for early death (Stoecklein NH, et al. Direct genetic analysis of single disseminated cancer cells for prediction of outcome and therapy selection in esophageal cancer. Cancer Cell. 2008 May;13(5):441-53; http://www.ncbi.nlm.nih.gov/pubmed/18455127).

The abovementioned studies indicate that CTC blood tests have been successfully used to track the severity of a cancer or efficacy of a treatment. In conclusion, the evolution of the CTC technology will be critical in the emerging area of targeted therapy. With the development and use of new technologies, the links between the genomic information and CTC could be explored and established for targeted therapy.

Challenges in CTC research

Potential clinical significance of CTC has been demonstrated as early detection, diagnostic, prognostic, predictive, surrogate, stratification, and pharmacodynamic biomarkers. Hong B and Zu Y (2013) discuss that “the role of CTC as a disease marker may be unique in different clinical conditions and should be carefully interpreted. A good example is the comparison between the prognostic and predictive biomarkers. Both biomarkers employ progression-free survival and overall survival for data interpretation; however, the prognostic biomarker is independent of specific drug treatment or therapy, and used for the determination of outcomes before treatment, while the predictive biomarker is related to a particular treatment to predict the response. Furthermore, inconsistent results are increasingly reported among the various CTC assay methods, specifically pertaining to results for the CTC detection rate, patient positivity rate, and the correlation between the presence of CTC and survival rate (Hong B and Zu Y. Detecting circulating tumor cells: current challenges and new trends. Source. Theranostics. 2013 Apr 23;3(6):377-94; http://www.ncbi.nlm.nih.gov/pubmed/23781285).
Heterogeneity in CTC along with several other technical factors contribute to discordance, including the changes in methodology, lack of reference standard, spectrum and selection bias, operator variability and bias, sample size, blurred clinical impact with known clinical/pathologic data, use of diverse capture antibodies from different sources, lack of awareness of the pre-analytical phase, oversimplification of the cytopathology process, use of dichotomous decision criteria, etc (Sturgeon C. Limitations of assay techniques for tumor markers. In: (ed.) Diamandis EP, Fritsche HA, Lilja H, Chan DW, Schwartz MK. Tumor markers: physiology, pathobiology, technology, and clinical applications. Washington, DC: AACC Press. 2002:65-82; Gion M and Daidone MG. Circulating biomarkers from tumour bulk to tumour machinery: promises and pitfalls. Eur J Cancer. 2004;40(17):2613-2622; http://www.ncbi.nlm.nih.gov/pubmed/15541962). Therefore, employing a standard protocol is essential in order to minimize a lot of inconsistencies and technical errors.
CTC in a small amount of blood sample might not represent the actual CTC count in the whole blood. In fact, it has been reported that the Cell Search system might undercount the number of CTC. Nagrath et al (2007) have demonstrated that the average CTC number per mL of whole blood is approximately 79-155 in various cancers (Nagrath S, et al. Isolation of rare circulating tumous cells in cancer patients by microchip technology. Nature. 2007;450(7173):1235-1239; http://www.ncbi.nlm.nih.gov/pubmed/18097410). In addition, an investigative CellSearch Profile approach (for research use only) detected an approximately 30-fold higher number of the median CTC in the same paired blood samples (Flores LM, et al. Improving the yield of circulating tumour cells facilitates molecular characterisation and recognition of discordant HER2 amplification in breast cancer. Br J Cancer. 2010;102(10):1495-502; http://www.ncbi.nlm.nih.gov/pubmed/20461092). Such measurement discrepancies indicate that the actual CTC numbers in the blood of patients could be at least 30-100 fold higher than that currently reported by the only FDA-cleared CellSearch system.

Thus, although promising, the CTC technology faces several challenges both in detection and interpretation, which has resulted in its limited clinical acceptance and use. In order to prepare the CTC technology for future widespread clinical acceptance, a comprehensive guideline for all phases of CTC technology development was published by the Foundation for the National Institutes of Health (FNIH) Biomarkers Consortium. The guidelines describe methods for interactive comparisons of proprietary new technologies, clinical trial designs, a clinical validation qualification strategy, and an approach for effectively carrying out this work through a public-private partnership that includes test developers, drug developers, clinical trialists, the FDA and the National Cancer Institute (NCI) (Parkinson DR, et al. Considerations in the development of circulating tumor cell technology for clinical use. J Transl Med. 2012;10(1):138; http://www.ncbi.nlm.nih.gov/pubmed/22747748).

Reference:

Langley RR and Fidler IJ. Tumor cell-organ microenvironment interactions in the pathogenesis of cancer metastasis. Endocr Rev. 2007 May;28(3):297-321; http://www.ncbi.nlm.nih.gov/pubmed/17409287
Husemann Y et al. Systemic spread is an early step in breast cancer. Cancer Cell. 2008 Jan;13(1):58-68; http://www.ncbi.nlm.nih.gov/pubmed/18167340
Chiang AC and Massagué J. Molecular basis of metastasis. N Engl J Med. 2008 Dec 25;359(26):2814-23; http://www.ncbi.nlm.nih.gov/pubmed/19109576
Vona G, et al, Isolation by size of epithelial tumor cells : a new method for the immunomorphological and molecular characterization of circulating tumor cells. Am J Pathol, 2000 Jan;156(1):57-63; http://www.ncbi.nlm.nih.gov/pubmed/10623654
Baccelli I, et al. Identification of a population of blood circulating tumor cells from breast cancer patients that initiates metastasis in a xenograft assay. Nature Biotechnology 2013 31, 539–544; http://www.ncbi.nlm.nih.gov/pubmed/23609047
Cristofanilli M, et al, Circulating tumor cells, disease progression, and survival in metastatic breast cancer. N Engl J Med. 2004 Aug 19;351(8):781-91; http://www.ncbi.nlm.nih.gov/pubmed/15317891
Miller MC, et al. Significance of Circulating Tumor Cells Detected by the CellSearch System in Patients with Metastatic Breast Colorectal and Prostate Cancer. J Oncol. 2010; http://www.ncbi.nlm.nih.gov/pubmed/20016752
Stoecklein NH, et al. Direct genetic analysis of single disseminated cancer cells for prediction of outcome and therapy selection in esophageal cancer. Cancer Cell. 2008 May;13(5):441-53; http://www.ncbi.nlm.nih.gov/pubmed/18455127
Hong B and Zu Y. Detecting circulating tumor cells: current challenges and new trends. Source. Theranostics. 2013 Apr 23;3(6):377-94; http://www.ncbi.nlm.nih.gov/pubmed/23781285
10. Sturgeon C. Limitations of assay techniques for tumor markers. In: (ed.) Diamandis EP, Fritsche HA, Lilja H, Chan DW, Schwartz MK. Tumor markers: physiology, pathobiology, technology, and clinical applications. Washington, DC: AACC Press. 2002:65-82
Gion M and Daidone MG. Circulating biomarkers from tumour bulk to tumour machinery: promises and pitfalls. Eur J Cancer. 2004;40(17):2613-2622; http://www.ncbi.nlm.nih.gov/pubmed/15541962
Nagrath S, et al. Isolation of rare circulating tumous cells in cancer patients by microchip technology. Nature. 2007;450(7173):1235-1239; http://www.ncbi.nlm.nih.gov/pubmed/18097410
Flores LM, et al. Improving the yield of circulating tumour cells facilitates molecular characterisation and recognition of discordant HER2 amplification in breast cancer. Br J Cancer. 2010;102(10):1495-502; http://www.ncbi.nlm.nih.gov/pubmed/20461092
Chaffer CL and Weinberg RA. Science 2011,331, pp. 1559-1564; http://www.ncbi.nlm.nih.gov/pubmed/21436443

Mesothelin: An early detection biomarker for cancer (By Jack Andraka)

Posted in Advanced Drug Manufacturing Technology, Bio Instrumentation in Experimental Life Sciences Research, Biological Networks, Gene Regulation and Evolution, Biomarkers & Medical Diagnostics, BioSimilars, CANCER BIOLOGY & Innovations in Cancer Therapy, Cancer Prevention: Research & Programs, Cell Biology, Signaling & Cell Circuits, Disease Biology, Small Molecules in Development of Therapeutic Drugs, Health Economics and Outcomes Research, Medical Devices R&D Investment, Nanotechnology for Drug Delivery, Pharmaceutical R&D Investment, Population Health Management, Genetics & Pharmaceutical, Regulated Clinical Trials: Design, Methods, Components and IRB related issues, Technology Transfer: Biotech and Pharmaceutical, tagged Blood test, carbon nanotubes, early detection, Mesothelin, Pancreatic cancer on April 21, 2013| 8 Comments »

Mesothelin: An early detection biomarker for cancer (By Jack Andraka)

Author/ Curator: Tilda Barliya PhD

I was recently amazed to read about a young teen who scooped the headlines with his story: Jack Andraka created an early detection test for pancreatic cancer (PC) (1). While we extensively discussed pancreatic cancer in previous posts (1b), this one deserve it’s on attention.

Andraka tells the audience about his journey from learning about a the family member diagnosed with PC, to a flash insight while learning about carbon nanotubes during a biology class, through the screening and finding one protein out of thousands and all the way up his final discovery. His journey wasn’t easy to say the least, he story though deserve all the applause.

Starting with his journey, Andraka began by “looking for a protein in the bloodstream that would be a biomarker for pancreatic cancer, one that would be found in all cases, even in the earliest stages”. He finally narrowed it down to the one that could work – Mesothelin.

So what is mesothelin?

Model for peritoneal metastasis of ovarian tumors. A model showing the importance of MUC16-mesothelin interaction in the peritoneal metastasis of ovarian tumors is shown.

Gubbels JA, et al. Mol. Cancer (2006). Model for peritoneal metastasis of ovarian tumors.

Mesothelin is a 4o kDa secreted protein expressed in normal mesothelial cells and over-expressed in several human tumors including mesothelioma, ovarian and pancreatic adenocarcinoma (2,3). Although the full mechanism by which mesothelin work is still unsolved, it is postulated thought, that mesothelin growth and apoptosis of pancreatic cancer cells by a p53 -dependent and independent pathways (7).

Andraka’s method:

human mesothelin-specific antibodies were mixed with single walled carbon nanotubes and used to coat strips of ordinary filter paper. This made the paper conductive. The optimal layering was determined using a scanning electron microscope. Cell media spiked with varying amounts of mesothelin was then tested against the paper biosensor and any change in the electrical potential of the sensor strip (due to the changing conductivity of the nanotubes) was measured, before and after each application.

The antibodies would bind to the mesothelin and enlarge. These beefed-up molecules would spread the nanotubes farther apart, changing the electrical properties of the network: The more mesothelin present, the more antibodies would bind and grow big, and the weaker the electrical signal would become.

A dose-response curve was constructed with an R2 value of .9992. Tests on human blood serum obtained from both healthy people and patients with chronic pancreatities, pancreatic intraepithelial neoplasia (a precursor to pancreatic carcinoma), or pancreatic cancer showed a similar response. The sensor’s limit of detection sensitivity was found to be 0.156 ng/mL; 10 ng/mL is considered the level of overexpression of mesothelin consistent with pancreatic cancer. Andraka’s sensor costs $0.03 (to compare to a $800 cost of a standard test) and 10 tests can be performed per strip, taking 5 minutes each. The method is 168 times faster, 26,667 times less expensive, and 400 times more sensitive than ELISA, and 25% to 50% more accurate than the CA19-9 test (5).

More so, Wang K and colleagues showed that inhibition of mesothelin may be used as novel strategy for targeting cancer cells (6). The authors showed that silencing the MSLN gene, encoding for mesothelin, inhibits cell proliferation and invasion. While this work is very impressive, the authors haven’t evaluated the potential use these siRNA in animal studies.

In summary:

It is very exiting to know that we may now have a simple and cheap blood test that has the huge potential to save many lives. All we need to do now is to conduct a multinational large scale screening for potential patients.

Andraka on his part is very hopeful, he believes “it could potentially be used to test for ovarian and lung cancer too. And by switching out the protein the test reacts to, it could — down the road — be used for diseases as varied as heart disease and HIV/AIDS”.

Ref:

1. By: Kate Torgovnich . An early detection test for pancreatic cancer: Jack Andraka at TED2013.http://blog.ted.com/2013/02/27/an-early-detection-test-for-pancreatic-cancer-jack-andraka-at-ted2013/

1b. By; Tilda Barliya PhD. Pancreatic Cancer: Genetics, Genomics and Immunotherapy. http://pharmaceuticalintelligence.com/2013/04/11/update-on-pancreatic-cancer/

2. Mesothelin. http://en.wikipedia.org/wiki/Mesothelin

3. Nathalie Scholler. Mesothelin. http://www.med.upenn.edu/schollerlab/user_documents/Scholler%20Encyclopedia%20of%20Cancer%202008.pdf

4. Argani P, Iacobuzio-Donahue C, Ryu B, Rosty C, Goggins M, Wilentz RE, Murugesan SR, Leach SD, Jaffee E, Yeo CJ, Cameron JL, Kern SE and Hruban RH. Mesothelin is overexpressed in the vast majority of ductal adenocarcinomas of the pancreas: identification of a new pancreatic cancer marker by serial analysis of gene expression (SAGE). Clin Cancer Res. 2001 Dec;7(12):3862-3868. http://clincancerres.aacrjournals.org/content/7/12/3862.long

5. Jack Andraka and Glen Burnie, MD. A Novel Paper Sensor for the Detection of Pancreatic Cancer. http://apps.societyforscience.org/intelisef2012/project.cfm?PID=ME028&CFID=28485&CFTOKEN=10931553

6. Wang K, Bodempudi V, Liu Z, Borrego-Diaz E, Yamoutpoor F, et al. (2012) Inhibition of Mesothelin as a Novel Strategy for Targeting Cancer Cells. PLoS ONE 7(4): e33214. doi:10.1371/journal.pone.0033214. http://www.plosone.org/article/info:doi/10.1371/journal.pone.0033214

7. Zheng C, Jia W, Tang Y, Zhao HL, Jiang Y and Sun S. Mesothelin regulates growth and apoptosis in pancreatic cancer cells through p53-dependent and -independent signal pathway. Journal of Experimental & Clinical Cancer Research 2012, 31:84. http://www.jeccr.com/content/pdf/1756-9966-31-84.pdf

Blood markers for Alzheimer’s disease

Posted in Alzheimer's Disease, tagged Alzheimer, Alzheimer's Disease Neuroimaging Initiative, Alzheimers Disease, Blood test, cerebrospinal fluid, Emory University School of Medicine, protein, Washington University in St. Louis on September 5, 2012| 2 Comments »

Reported by Dr. Venkat S Karra, Ph.D.

A series of proteins in blood could form the basis of a test for Alzheimer’s disease in the future, say scientists in the US. They employed proteomics to identify proteins that were expressed at different levels in the blood of patients with Alzheimer’s disease or mild cognitiive impairment compared with those of healthy control patients. The results are described in Neurology.

Four plasma analytes remained after cross-checking against the findings of the Alzheimer’s Disease Neuroimaging Initiative (ADNI). They are apolipoprotein E, B-type natriuretic peptide, C-reactive protein and pancreatic polypeptide. Their levels also correlated with the cerebrospinal fluid contents of beta-amyloid proteins, which have been associated with the onset of Alzheimer’s disease. It is still too early to say for sure that a blood test based on these proteins would work. One of the next steps should be to confirm the link between the biomarkers in blood and cerebrospinal fluid.

source: spectroscopynow