Clinical utility of comprehensive circulating tumor DNA genotyping compared with standard of care tissue testing in patients with newly diagnosed metastatic colorectal cancer

BACKGROUND

Comprehensive biomarker testing is essential in selecting optimal treatment for patients with metastatic colorectal cancer (mCRC); however, incomplete genotyping is widespread, with most patients not receiving testing for all guideline-recommended biomarkers, in part due to reliance on burdensome sequential tissue-based single-biomarker tests with long waiting times or availability of only archival tissue samples. We aimed to demonstrate that liquid biopsy, associated with rapid turnaround time (TAT) and lower patient burden, effectively identifies guideline-recommended biomarkers in mCRC relative to standard of care (SOC) tissue testing.

PATIENTS AND METHODS

Prospectively enrolled patients with previously untreated mCRC undergoing physician discretion SOC tissue genotyping submitted pretreatment blood samples for comprehensive circulating tumor DNA (ctDNA) analysis with Guardant360 and targeted RAS and BRAF analysis with OncoBEAM.

RESULTS

Among 155 patients, physician discretion SOC tissue genotyping identified a guideline-recommended biomarker in 82 patients, versus 88 identified with comprehensive ctDNA (52.9% versus 56.8%, noninferiority demonstrated down to α = 0.005) and 69 identified with targeted PCR ctDNA analysis (52.9% versus 44.5%, noninferiority rejected at α = 0.05). Utilizing ctDNA in addition to tissue increased patient identification for a guideline-recommended biomarker by 19.5% by rescuing those without tissue results either due to tissue insufficiency, test failure, or false negatives. ctDNA median TAT was significantly faster than tissue testing when the complete process from sample acquisition to results was considered (median 10 versus 27 days, P < 0.0001), resulting in accelerated biomarker discovery, with 52.0% biomarker-positive patients identified by ctDNA versus 10.2% by SOC tissue 10 days after sample collection (P < 0.0001).

CONCLUSIONS

Comprehensive ctDNA genotyping accurately identifies guideline-recommended biomarkers in patients with mCRC at a rate at least as high as SOC tissue genotyping, in a much shorter time. Based on these findings, the addition of ctDNA genotyping to clinical practice has significant potential to improve the care of patients with mCRC.

Multicentre validation of a microRNA-based assay for diagnosing indeterminate thyroid nodules utilising fine needle aspirate smears

AIMS

The distinction between benign and malignant thyroid nodules has important therapeutic implications. Our objective was to develop an assay that could classify indeterminate thyroid nodules as benign or suspicious, using routinely prepared fine needle aspirate (FNA) cytology smears.

METHODS

A training set of 375 FNA smears was used to develop the microRNA-based assay, which was validated using a blinded, multicentre, retrospective cohort of 201 smears. Final diagnosis of the validation samples was determined based on corresponding surgical specimens, reviewed by the contributing institute pathologist and two independent pathologists. Validation samples were from adult patients (≥18 years) with nodule size >0.5 cm, and a final diagnosis confirmed by at least one of the two blinded, independent pathologists. The developed assay, RosettaGX Reveal, differentiates benign from malignant thyroid nodules, using quantitative RT-PCR.

RESULTS

Test performance on the 189 samples that passed quality control: negative predictive value: 91% (95% CI 84% to 96%); sensitivity: 85% (CI 74% to 93%); specificity: 72% (CI 63% to 79%). Performance for cases in which all three reviewing pathologists were in agreement regarding the final diagnosis (n=150): negative predictive value: 99% (CI 94% to 100%); sensitivity: 98% (CI 87% to 100%); specificity: 78% (CI 69% to 85%).

CONCLUSIONS

A novel assay utilising microRNA expression in cytology smears was developed. The assay distinguishes benign from malignant thyroid nodules using a single FNA stained smear, and does not require fresh tissue or special collection and shipment conditions. This assay offers a valuable tool for the preoperative classification of thyroid samples with indeterminate cytology.

The effects of telomere shortening on cancer cells: a network model of proteomic and microRNA analysis

Previously, we have shown that shortening of telomeres by telomerase inhibition sensitized cancer cells to cisplatinum, slowed their migration, increased DNA damage and impaired DNA repair. The mechanism behind these effects is not fully characterized. Its clarification could facilitate novel therapeutics development and may obviate the time consuming process of telomere shortening achieved by telomerase inhibition. Here we aimed to decipher the microRNA and proteomic profiling of cancer cells with shortened telomeres and identify the key mediators in telomere shortening-induced damage to those cells. Of 870 identified proteins, 98 were differentially expressed in shortened-telomere cells. 47 microRNAs were differentially expressed in these cells; some are implicated in growth arrest or act as oncogene repressors. The obtained data was used for a network construction, which provided us with nodal candidates that may mediate the shortened-telomere dependent features. These proteins' expression was experimentally validated, supporting their potential central role in this system.

Tumor microRNA-29a expression and the risk of recurrence in stage II colon cancer

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Background: To compare the microRNA (miRNA) profiles in the primary tumor of patients with recurrent and non-recurrent colon cancer. Methods: The study population included 110 patients, 51 (46%) with stage I and 59 (54%) with stage II disease, who underwent curative colectomies between 1995-2005 without adjuvant therapy and for whom reliable miR expression data was available. RNA was extracted from formalin-fixed paraffin-embedded tumor samples. Initial profiling, using microarrays, was done in order to identify potential biomarkers of recurrence. The miRNA expression was later verified by quantitative real-time polymerase chain reaction (qRT-PCR). Findings were compared between patients who had a recurrence within 36 months of surgery (bad prognosis group, n=23, 21%) and those who did not (good prognosis group, n=87, 79%) in the entire group and within each stage. Results: In stage I, none of the 903 miRNAs tested showed differential expression between patients with good prognosis compared with those with bad prognosis. In stage II, one miRNA, miR-29a, showed a clear differential expression between the groups (p=0.028). High expression of miR-29a was associated with a longer disease-free survival (DFS), on both univariate and multivariate analyses. Using miR-29a, the positive predictive value for non-recurrence was 94% (2 recurrences among 31 patients). The differential expression of miR-29a was verified by qRT-PCR, showing a similar impact of this miR on DFS. Conclusions: This study demonstrated a significant impact of miR-29a on the risk of recurrence in patients with stage II but not in patients with stage I colon cancer.

Tumor microRNA-29a expression and the risk of recurrence in stage II colon cancer

There is emerging evidence for the prognostic role of various microRNA (miRNA) molecules in colon cancer. The aim of this study was therefore to compare the miRNA profiles in the primary tumor of patients with recurrent and non-recurrent colon cancer. The study population included 110 patients, 51 (46%) with stage I and 59 (54%) with stage II disease, who underwent curative colectomies between 1995 and 2005 without adjuvant therapy and for whom reliable miRNA expression data were available. RNA was extracted from formalin-fixed paraffin-embedded (FFPE) tumor samples. Initial profiling, using microarrays, was done in order to identify potential biomarkers of recurrence. The miRNA expression was later verified by quantitative real-time polymerase chain reaction (qRT-PCR). Findings were compared between patients who had a recurrence within 36 months of surgery (bad prognosis group, n=23, 21%) and those who did not (good prognosis group, n=87, 79%) in the entire group and within each stage. The results showed that in stage I, none of the 903 miRNAs tested showed differential expression between patients with good prognosis compared with those with poor prognosis. In contrast, in stage II, one miRNA, miR-29a, showed a clear differential expression between the groups (p=0.028). High expression of miR-29a was associated with a longer disease-free survival (DFS), on both univariate and multivariate analyses. Using miR-29a, the positive predictive value for non-recurrence was 94% (2 recurrences among 31 patients). The differential expression of miR-29a was verified by qRT-PCR, showing a similar impact of this miR on DFS. In conclusion, this study demonstrated a significant impact of miR-29a on the risk of recurrence in patients with stage II but not in patients with stage I colon cancer. Based on these results, a validation study is planned.

Serum levels of microRNAs in patients with heart failure

AIMS

Diagnosis and risk stratification of patients with heart failure remain a challenge. The small non-coding RNAs known as microRNAs regulate gene expression and seem to play an important role in the pathogenesis of heart failure. In the current study, we aim to characterize the levels of microRNAs in the sera of chronic systolic heart failure patients vs. controls and assess the possible correlation between elevation in the levels of specific microRNAs and clinical prognostic parameters in heart failure patients.

METHODS AND RESULTS

The levels of 186 microRNAs were measured in the sera of 30 stable chronic systolic heart failure patients and 30 controls using quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The differences in microRNA levels between the two groups were characterized, and a score, based on the levels of four specific microRNAs with the most significant increase in the heart failure group (miR-423-5p, miR-320a, miR-22, and miR-92b), was defined. The score was used to discriminate heart failure patients from controls with a sensitivity and specificity of 90%. Moreover, in the heart failure group, there was a significant association between the score and important clinical prognostic parameters such as elevated serum natriuretic peptide levels, a wide QRS, and dilatation of the left ventricle and left atrium (r = 0.63, P = 3e-4; P = 0.009; P = 0.03; and P = 0.01, respectively).

CONCLUSIONS

Elevated serum levels of specific microRNAs: miR-423-5p, miR-320a, miR-22, and miR-92b, identify systolic heart failure patients and correlate with important clinical prognostic parameters.

MicroRNAs as a potential prognostic factor in gastric cancer

AIM: To compare the microRNA (miR) profiles in the primary tumor of patients with recurrent and non-recurrent gastric cancer.

METHODS: The study group included 45 patients who underwent curative gastrectomies from 1995 to 2005 without adjuvant or neoadjuvant therapy and for whom adequate tumor content was available. Total RNA was extracted from formalin-fixed paraffin-embedded tumor samples, preserving the small RNA fraction. Initial profiling using miR microarrays was performed to identify potential biomarkers of recurrence after resection. The expression of the differential miRs was later verified by quantitative real-time polymerase chain reaction (qRT-PCR). Findings were compared between patients who had a recurrence within 36 mo of surgery (bad-prognosis group, n = 14, 31%) and those who did not (good-prognosis group, n = 31, 69%).

RESULTS: Three miRs, miR-451, miR-199a-3p and miR-195 were found to be differentially expressed in tumors from patients with good prognosis vs patients with bad prognosis (P < 0.0002, 0.0027 and 0.0046 respectively). High expression of each miR was associated with poorer prognosis for both recurrence and survival. Using miR-451, the positive predictive value for non-recurrence was 100% (13/13). The expression of the differential miRs was verified by qRT-PCR, showing high correlation to the microarray data and similar separation into prognosis groups.

CONCLUSION: This study identified three miRs, miR-451, miR-199a-3p and miR-195 to be predictive of recurrence of gastric cancer. Of these, miR-451 had the strongest prognostic impact.

Abstract 4943: microRNAs as clinical biomarkers for lung cancer classification

Background: Lung cancers have traditionally been subdivided into two main groups: Small Cell Lung Cancer (SCLC) and Non Small Cell Lung Cancer (NSCLC). Due to limited tumor sample amounts and an abundance of poor quality samples, accurate subclassification of primary lung cancer using small pre-operative biopsies presents a diagnostic challenge using current tools (H&E and immunohistochemical stains). For patients with primary lung cancer, accurate determination of the tumor type significantly influences treatment decisions. Our previous studies have shown that microRNAs are differentially expressed in different subtypes of lung cancer; hence microRNA expression profiling holds a promising new strategy for the precise subclassification of lung cancers. Based on these findings, we present here the development of a microRNA-based qRT-PCR diagnostic assay that uses pathology and cytology samples in order to classify primary lung cancers into four subtypes: squamous, non-squamous, SCLC and carcinoid.

Methods: FFPE tissue blocks and cell blocks from different histological subtypes of lung cancer, taken from primary lung cancer resection or pre-operative diagnostic procedures, were collected. High-quality RNA, including the well-preserved microRNA fraction, was extracted from the samples using proprietary protocols. Expression levels of potential microRNA biomarkers were profiled using a sensitive and specific qRT-PCR platform.

Results: We find that combinations of a few microRNAs can successfully differentiate between different histological types of lung tumors. A classification algorithm was developed that reached high accuracy in the identification of the four main subtypes of lung tumors.

Conclusion:

We developed a highly accurate microRNA-based diagnostic assay that classifies primary lung cancer types with very high sensitivity and specificity. This assay is a simple and reliable diagnostic assay which will offer an accurate and standardized tool for primary lung cancer cytological samples, including those that presently fail pathological evaluation.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 4943. doi:10.1158/1538-7445.AM2011-4943

Use of the Optimata Virtual Patient (OVP) to predict effects of sunitinib malate in advanced pancreatic cancer

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Background: Pancreatic cancer is considered to be incurable by available treatment modalities, with 5-year survival rate <4%. Sunitinib malate (Sutent) significantly increased progression-free survival in patients with advanced islet cell tumors (pancreatic); however, it demonstrated only modest single-agent effect in a phase II study in patients with metastatic pancreatic adenocarcinoma (PaC) that progressed after first-line therapy with gemcitabine. To improve the response of PaC patients to drugs, the interplay between biologic, pathologic, and pharmacologic processes underlying drug-patient interactions have been mathematically modeled, predicting efficacy responses, different toxicities, and long-term tolerability in clinical trials, allowing for improved dosing regimens and patient selection (OVP engine) (Agur Z., 2010). The OVP engine was used to predict Sunitinib malate single-agent activity in advanced PaC.

Methods: OVP replicated the observed growth patterns of human PaC. Pharmacokinetics (PK) and pharmacodynamics (PD) of sunitinib malate were modeled based on literature (NDA 21-938). Effects of sunitinib malate on human PaC xenografts were scaled to model PK/PD in human. To evaluate drug efficacy in advanced PaC patient-population, a Virtual PaC Patient- Population was created by replacing the population averaged parameter values in the model by their distribution in the population. Using this procedure, a large set of virtual patients was generated. Model simulations with sunitinib malate therapy (50 mg QD/28 days; 14 days rest [1 cycle]) enabled the prediction and classification of patients' response according to RECIST criteria and compared with the actual clinical response (O'Reilly et al, 2008).

Results: Simulations of the FDA-approved schedule, predicted a stable disease in 81% of the patients following one treatment cycle and 54% following two treatment cycles. Stable disease was predicted to be the best observed response, which was confirmed in the clinical study.

Conclusions: Our model predictions are compatible with clinical results of a recent phase II trial with the same treatment regimen of sunitinib malate (O'Reilly et al, 2008) and further suggest the use of mathematical model during drug development.

[Table: see text]

microRNAs as clinical biomarkers for lung cancer classification

Background: Lung cancers have been traditionally subdivided into two main groups: neuroendocrine and non-small cell lung cancer (NSCLC). In 20-30% of lung cancer cases it is difficult to make a definitive diagnosis of the tumor subtype based on the cytological specimen (e.g., fine-needle aspirates). In general, the classification of lung cancers poses a diagnostic challenge and there is lack of standardized techniques for cancer sub-typing. For patients with lung carcinoma, accurate determination of tumor type significantly influences treatment decision. MicroRNA expression profiling is a promising new strategy for the precise subclassification of lung cancers. We have previously described a microRNA-based assay which accurately differentiates between squamous and non-squamous NSCLC in FFPE derived from resections as well as from cytological samples. We have also used microRNA microarray data generated from over a hundred formalin-fixed, paraffin-embedded (FFPE) samples of primary lung cancer, to identify microRNA expression profiles that differ significantly for various sub-types of lung cancer samples. Based on these findings, we present here the development of a microRNA-based assay that is able to differentiate primary lung cancers into neuroendocrine vs. NSCLC and then further sub-classify NSCLC into squamous vs. non-squamous and neuroendocrine into SCLC vs. carcinoid using pathology and cytology samples.

Methods: FFPE of resections and cell blocks from different histological subtypes of lung cancer, taken from primary lung cancer resection or pre-operative diagnostic procedures, were collected. High-quality RNA, including the well-preserved microRNA fraction, was extracted from the samples using proprietary protocols. Expression levels of potential microRNA biomarkers were profiled using a sensitive and specific qRT-PCR platform.

Results: We find that combinations of small numbers of microRNAs can successfully differentiate between the four different histological types of lung cancers, with very high sensitivity and specificity. These microRNAs are able to subclassify lung cancer FFPE samples derived from pathological and cytological samples.

Conclusion: We identified microRNAs that represent excellent biomarkers for the classification of lung primary cancers. These findings are the basis for the development of a simple and reliable qRT-PCR based diagnostic assay which will offer an accurate and standardized tool for primary lung cancer pathological and cytological samples, including those that presently fail pathological evaluation.

Abstract 3017: MicroRNAs as prognostic indicators in gastric cancer

Background: Our ability to determine the prognosis of an individual patient with gastric cancer and thereby to select patients for adjuvant therapy is still limited. Preliminary data suggest that microRNAs may have a prognostic role in this disease. We hence decided to compare the microRNA profiles in the primary tumor of patients with recurrent and non-recurrent gastric cancer and to evaluate the prognostic impact of these molecules.

Patients and Methods: Eligible patients, who underwent curative gastrectomies between 1995 and 2005 and did not receive any pre- or postoperative adjuvant therapy, were identified from the database of the participating institutions. Total RNA was extracted from tumor formalin-fixed paraffin embedded (FFPE) samples using proprietary protocols that preserve the small RNA fraction. Initial profiling using microRNA microarrays identified potential microRNA biomarkers that can be used to predict recurrence of gastric cancer after resection. The expression of differential microRNAs, was verified by qRT-PCR.

Results: Forty-five eligible patients had adequate tumor content and microRNA expression data and were included in the analysis. Of these, 14 (31%) experienced recurrence of disease within three years from surgery (“bad prognosis” group) and 31 (69%) did not (“good prognosis” group). Advanced pathological stage and extensive surgical procedure correlated with bad prognosis. Signal levels of three microRNAs were found to be significantly differentially expressed in tumors from patients with good prognosis vs. patients with bad prognosis. High expression of each of these microRNAs was associated with significantly poorer prognosis for both recurrence and survival. Proprietary microRNA qRT-PCR showed a high correlation to microarrays and similar separation into prognosis groups based on microRNA expression.

Conclusion: We identified a set of microRNAs whose high expression was predictive of tumor recurrence and poor prognosis in patients with gastric cancer. This finding provides a basis for a novel tool for risk stratification in this disease and allows further insight into its pathogenesis. Based on these results, a validation study, on a larger and independent cohort of patients, is planned.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3017.

Abstract 4054: Prognostic value of microRNAs expression in diffuse large B cell lymphoma

Background: Diffuse large cell lymphoma (DLBCL) is heterogeneous in its clinical sequel. Approximately 50% of patients relapse after treatment and many succumb to the disease. Risk stratification of these patients is based mainly on the International Prognostic Index (IPI), while molecular profiling is not widely used for prognostication. Thus, there exists a need for identification of additional biomarkers that can be used as prognostic indicators for patients with DLBCL. Here we propose microRNAs, a family of small non-coding regulatory RNAs involved in cancer development, as an emerging class of potential biomarkers for risk stratification of DLBCL.

Methods: Expression profiling of microRNAs was performed on RNA extracted from biopsy specimens of 83 DLBCL patients diagnosed and treated at Rabin Medical Center, using custom microRNAs microarrays. All patients were treated with CHOP or CHOP like therapy and were dichotomized into a “good prognosis” group (patients that achieved complete remission and no relapse within 5 years) and a “bad prognosis” group (patients that were either resistant to treatment or relapsed within 9 months). Expression levels were compared between the two groups of samples and statistically analyzed. The expression of differential microRNAs was verified using a microRNA qRT-PCR platform.

Results: We found that several microRNAs are significantly differentially expressed in tumors from patients with bad prognosis compared with patients with good prognosis. Proprietary microRNA qRT-PCR showed a high correlation to microarrays and similar separation into prognosis groups based on miR expression.

Conclusion: In summary, according to the results of this study, miRNA expression can serve as a novel tool for risk stratification and prognosis prediction of DLBCL patients. This approach can potentially be used to tailor treatment and further management to specific patient needs.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 4054.

Telomere shortening sensitizes cancer cells to selected cytotoxic agents: in vitro and in vivo studies and putative mechanisms

Background

Telomere/telomerase system has been recently recognized as an attractive target for anticancer therapy. Telomerase inhibition results in tumor regression and increased sensitivity to various cytotoxic drugs. However, it has not been fully established yet whether the mediator of these effects is telomerase inhibition per se or telomere shortening resulting from inhibition of telomerase activity. In addition, the characteristics and mechanisms of sensitization to cytotoxic drugs caused by telomerase inhibition has not been elucidated in a systematic manner.

Methodology/Principal Findings

In this study we characterized the relative importance of telomerase inhibition versus telomere shortening in cancer cells. Sensitization of cancer cells to cytotoxic drugs was achieved by telomere shortening in a length dependent manner and not by telomerase inhibition per se. In our system this sensitization was related to the mechanism of action of the cytotoxic drug. In addition, telomere shortening affected also other cancer cell functions such as migration. Telomere shortening induced DNA damage whose repair was impaired after administration of cisplatinum while doxorubicin or vincristine did not affect the DNA repair. These findings were verified also in in vivo mouse model. The putative explanation underlying the phenotype induced by telomere shortening may be related to changes in expression of various microRNAs triggered by telomere shortening.

Conclusions/Significance

To our best knowledge this is the first study characterizing the relative impact of telomerase inhibition and telomere shortening on several aspects of cancer cell phenotype, especially related to sensitivity to cytotoxic drugs and its putative mechanisms. The microRNA changes in cancer cells upon telomere shortening are novel information. These findings may facilitate the development of telomere based approaches in treatment of cancer.

Clinical relevance of miRNA expression in metastatic melanoma

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Background: We recently reported the identification of a specific miRNA cluster frequently overexpressed in melanoma which enhances the metastatic behavior (Segura et al., 2009. PNAS. In press). In this study, we aim to define the clinical relevance of miRNA expression, in particular whether miRNAs can serve as prognostic biomarkers for melanoma patients. Methods: Total RNA was extracted from formalin-fixed paraffin embedded (FFPE) tissue samples from 61 metastatic melanoma specimens (25 lymph node, 16 soft tissue/skin, 13 brain and 7 visceral) accrued by the NYU Interdisciplinary Melanoma Cooperative Group (IMCG). RNA was hybridized into miRNA arrays (miRdicatorTM, Rosetta Genomics, Inc) containing probes for more than 600 miRNA sequences, including all the human miRNAs in the 9.0 version of miRBase. The Significance Analysis of Microarrays (SAM) was used to identify miRNAs significantly associated with survival, and the False Discovery Rate (FDR) approach was used to adjust for multiple comparisons. Results: We identified a signature of 18 miRNAs, whose up-regulation significantly associates with better prognosis (increased overall survival and post-recurrence survival) using the FDR of 0%. Quantitative RT-PCR on the same tissues has verified the array results in 15 out of 15 miRNAs analyzed. Some of these miRNAs were significantly associated with stage at recurrence, while others significantly correlated with the site of metastasis (i.e. visceral, brain, soft-tissue). Using cross-validation, we selected a miRNA signature consisting of 10 of these significant miRNAs with lowest misclassification error in predicting 1.5-year post-recurrence survival. We are currently validating these findings in a separate cohort of metastatic patients. Furthermore, we are investigating whether these ‘protective' miRNAs can be detected in the corresponding primary lesions and thus, whether they already hold prognostic value at early stages of the disease. Conclusions: Our data suggest a role for miRNAs as melanoma biomarkers, and support the development of miRNA- based monitoring assays. These analyses are also expanding our understanding of the molecular alterations underlying melanoma progression, by revealing miRNAs whose down-regulation associates with a more aggressive biological behavior.

[Table: see text]

Circulating microRNAs as potential blood-based biomarkers for detection of colorectal cancer

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Background: Colorectal cancer (CRC) is one of the leading causes of cancer death worldwide. While there is a strong correlation between stage and prognosis in this disease, current screening methods for CRC have significant limitations, and newer technological approaches are desired. Circulating nucleic acids in body fluids have been studied as a source for diagnostic information and for cancer screening, yet the potential of microRNAs, a family of small non-coding regulatory RNAs, has not yet been thoroughly explored. Here we investigated the utility of microRNAs as potential serum biomarkers for early detection of CRC. Methods: We developed protocols for extracting and quantifying microRNA levels in serum. Serum levels of more than 350 microRNAs were measured using qRT-PCR on samples from 10 healthy controls and 10 CRC patients. Most microRNAs showed consistent levels across different individuals. A subset of microRNAs had significant differences in abundance between the two groups and was studied on a larger cohort of 118 patients and controls. Results: We initially identified a subset of microRNAs that showed significant differential abundance between sera of CRC patients and controls. Measuring the serum levels of 22 microRNAs on a cohort of 118 patients and controls, we showed that levels of circulating microRNAs can be very informative in the identification of CRC. Conclusions: The results demonstrate the potential of the microRNA processing and analysis methods that we developed. Certain microRNAs were found in different amounts in sera of CRC patients compared to healthy controls. Thus, circulating microRNAs represent promising candidates for diagnostic biomarkers in CRC.

[Table: see text]

Serum microRNAs are promising novel biomarkers

Background

Circulating nucleic acids (CNAs) offer unique opportunities for early diagnosis of clinical conditions. Here we show that microRNAs, a family of small non-coding regulatory RNAs involved in human development and pathology, are present in bodily fluids and represent new effective biomarkers.

Methods and Results

After developing protocols for extracting and quantifying microRNAs in serum and other body fluids, the serum microRNA profiles of several healthy individuals were determined and found to be similar, validating the robustness of our methods. To address the possibility that the abundance of specific microRNAs might change during physiological or pathological conditions, serum microRNA levels in pregnant and non pregnant women were compared. In sera from pregnant women, microRNAs associated with human placenta were significantly elevated and their levels correlated with pregnancy stage.

Conclusions and Significance

Considering the central role of microRNAs in development and disease, our results highlight the medically relevant potential of determining microRNA levels in serum and other body fluids. Thus, microRNAs are a new class of CNAs that promise to serve as useful clinical biomarkers.

Serum microRNAs are promising novel biomarkers

BACKGROUND

Circulating nucleic acids (CNAs) offer unique opportunities for early diagnosis of clinical conditions. Here we show that microRNAs, a family of small non-coding regulatory RNAs involved in human development and pathology, are present in bodily fluids and represent new effective biomarkers.

METHODS AND RESULTS

After developing protocols for extracting and quantifying microRNAs in serum and other body fluids, the serum microRNA profiles of several healthy individuals were determined and found to be similar, validating the robustness of our methods. To address the possibility that the abundance of specific microRNAs might change during physiological or pathological conditions, serum microRNA levels in pregnant and non pregnant women were compared. In sera from pregnant women, microRNAs associated with human placenta were significantly elevated and their levels correlated with pregnancy stage.

CONCLUSIONS AND SIGNIFICANCE

Considering the central role of microRNAs in development and disease, our results highlight the medically relevant potential of determining microRNA levels in serum and other body fluids. Thus, microRNAs are a new class of CNAs that promise to serve as useful clinical biomarkers.

Evolving pattern of Guillain-Barre syndrome in a community hospital in Israel

OBJECTIVES

To investigate the frequency of axonal Guillain-Barre syndrome (GBS) in our ward over 6 years (1999-2005).

MATERIALS AND METHODS

Clinical and electrophysiological findings of 40 patients admitted to neurology with abnormalities compatible with acute motor axonal neuropathy (AMAN), acute motor sensory axonal neuropathy (AMSAN) and acute inflammatory demyelinating polyneuropathy (AIDP) were reviewed.

RESULTS

Electrophysiological findings showed that 25 (63%) patients had AIDP, nine (22%) AMAN and six (15%) AMSAN. There were significant differences in disease severity. Most axonal patients (87%) were hospitalized with moderate or severe symptoms (3-4 Hughes grade score) and progressed to severe grade (4-6) in comparison with AIDP patients (64% admitted with mild forms) (1-2 Hughes grade score) and progressed to severe in 44% of cases. Cranial nerve involvement was more frequent in AIDP (56%) in comparison with the axonal type (13%). Raised cerebrospinal fluid protein at the time of hospitalization was observed in 76% of demyelinating and 33% of axonal patients.

CONCLUSIONS

Axonal GBS occurred more frequently in Israel compared with other Western countries.

Blockage of VIP during mouse embryogenesis modifies adult behavior and results in permanent changes in brain chemistry

Vasoactive intestinal peptide (VIP) regulates growth and development during the early postimplantation period of mouse embryogenesis. Blockage of VIP with a VIP antagonist during this period results in growth restriction, microcephaly, and developmental delays. Similar treatment of neonatal rodents also causes developmental delays and impaired diurnal rhythms, and the adult brains of these animals exhibit neuronal dystrophy and increased VIP binding. These data suggest that blockage of VIP during the development of the nervous system can result in permanent changes to the brain. In the current study, pregnant mice were treated with a VIP antagonist during embryonic days 8 through 10. The adult male offspring were examined in tests of novelty, paired activity, and social recognition. Brain tissue was examined for several measures of chemistry and gene expression of VIP and related compounds. Glial cells from the cortex of treated newborn mice were plated with neurons and examined for VIP binding and their ability to enhance neuronal survival. Treated adult male mice exhibited increased anxiety-like behavior and deficits in social behavior. Brain tissue exhibited regionally specific changes in VIP chemistry and a trend toward increased gene expression of VIP and related compounds that reached statistical significance in the VIP receptor, VPAC-1, in the female cortex. When compared to control astrocytes, astrocytes from treated cerebral cortex produced further increases in neuronal survival with excess synaptic connections and reduced VIP binding. In conclusion, impaired VIP activity during mouse embryogenesis resulted in permanent changes to both adult brain chemistry/cell biology and behavior with aspects of autism-like social deficits.

Diagnostic value of vestibular evoked myogenic potentials in cerebellar and lower-brainstem strokes

BACKGROUND

Vestibular evoked myogenic potentials (VEMPs) provide assessment of vestibular function. They consist in picking up compound muscle action potentials in the sternocleidomastoid (SCM) muscles in response to auditory stimulation of the vestibulum. VEMP testing has found application mainly in peripheral vestibular disorders, whereas reports about VEMPs in central vestibular lesions are rather scarce.

AIMS OF THE STUDY

Based on the physiological connections between the cerebellum and the vestibular nuclei, we investigated the influence on VEMPs of cerebellar and lower-brainstem strokes. We examined whether or not this method may be suitable as a clinical tool for the evaluation of the extent of cerebellar strokes.

PATIENTS AND METHODS

Nineteen patients with cerebellar ischemic stroke and 15 patients with lower-brainstem ischemic stroke (11 in the pons, four in the medulla) were included. The latencies and amplitudes of P13 and N23 in both groups of patients were compared with those obtained in a control group of 53 normal individuals.

RESULTS

VEMP responses were obtained in all patients and controls. At the group level, mean peak latencies and amplitudes, and the number of subjects with significantly deviant values did not differ between patients and controls. There were no latency or amplitude differences ipsilaterally or contralaterally to the lesion. At the individual level, there was no correlation between laterality of lesion and that of P13 or N23 abnormalities in patients with cerebellar strokes; however, there were two patients (one pontine, one medullar stroke) who presented P13 and N23 latency abnormalities ipsilaterally to the lesion.

CONCLUSION

Cerebellar strokes do not influence VEMPs. Moreover, despite previous reports, we were unable to find at a group level any statistically significant VEMP changes in patients with lower-brainstem strokes as compared with controls. Therefore, VEMPs do not appear a suitable tool for assessment of brainstem integrity in patients with posterior fossa strokes. However, they could constitute a sensitive method for documentation of involvement of the central vestibular pathways in patients with brainstem stroke.

[Opsoclonus myoclonus with ataxia]

Opsoclonus myoclonus with ataxia (OMA) is a rare neurological disorder. The syndrome is characterized by involuntary, conjugate, multidirectional eye movements accompanied by involuntary movements of limb or face, and sometimes ataxia, dysarthria, irritability, dementia, altered level of consciousness and even death. OMA is associated with various etiologies including infectious, toxic, drug-related, vascular and paraneoplastic conditions. Paraneoplastic opsoclonus myoclonus with ataxia (POMA) is more common in patients over 40 years of age and is usually associated with lung (especially small cell), breast and ovarian cancer but has also been reported with many other cancers. The syndrome is thought to be mediated by autoantibodies directed against onconeural antigens that are expressed by the tumor as well as by neurons. Studies from several laboratories were able to demonstrate a role for the cellular response in the pathogenesis of POMA. The results for treatment of this syndrome have been disappointing, although aggressive multimodality immunosuppressive treatments have been used. This is a case study of a patient with POMA who clearly demonstrates the difficulties in the diagnosis and treatment of this syndrome.

H reflex behavior in Parkinson's disease patients and patients with extrapyramidal and pyramidal signs combined

The H reflex was elicited in 21 normal subjects, 48 patients with Parkinson's disease (PD) and 22 patients with pyramidal and extrapyramidal signs combined (PESC). In most normal subjects (90.5%), in 29.2% of PD patients and 54.5% of patient with PESC the threshold for sensory fibers was lower than for motor fibers, and the H reflex was obtained before the M response for all duration stimuli in both legs. In 9.5% of normal subjects, 39.6% of PD patients with mild and moderate rigidity (according to the motor part of UPDRS) and 31.8% of patients with PESC, the threshold for the H reflex and M response was the same or the M response threshold was lower in at least one of the legs for short stimulus duration (0.1-0.2 ms). In 31.2% of PD patients (most of them with severe rigidity) and 13.7% of patients with PESC, the threshold for M response was lower for all stimulus duration in at least one of the legs, and it was obtained before H reflex. These very significant differences in behavior of the H reflex in PD patients (Fisher exact test, p<0.0001) that almost disappear in patients with PESC, could be possibly explained by changes in agonist-antagonist inhibition.

The role of gap junctions in seizures

Electrotonic synaptic communication between neurons via gap junctions (gjs) is increasingly recognized as an important synchronizing mechanism in the brain. At the same time, the biology of central nervous system (CNS) gjs is being unravelled. The pathogenesis of the abnormal neuronal synchrony underlying seizures, formerly thought to be based mainly on chemical synaptic transmission, now includes a role for gap junctional communication. This concept has been strengthened by evidence from several in vitro seizure models, in which pharmacological manipulations of gap junctional communication predictably affect the generation of seizures: blockers diminishing seizures and enhancers increasing the seizures. Evidence for interneurons, coupled in part by gjs, generating synchronous neural network activity including seizures, is presented. Also neuromodelling studies, which have enhanced our ability to understand the functional role that gap junctional communication plays in the generation and maintenance of neural synchrony and seizures, are presented. Gap junctional communication appears to be a promising target for the development of future anticonvulsant therapy.

Antineurofilament antibodies in postpolio syndrome

We determined the levels of antineurofilament antibodies in 29 patients with postpolio syndrome (PPS), 26 stable postpolio (PP) patients, 22 patients with ALS, and 20 normal controls (NCs). Patients with PPS had higher antibody levels to cholinergic neurofilaments than did all other groups. PP patients and those with ALS had antibody levels similar to those of NCs. The antibody binding level showed no relation to the age of the patients, duration of disease, or motor score.

Nitrite adulteration of workplace urine drug-testing specimens. I. Sources and associated concentrations of nitrite in urine and distinction between natural sources and adulteration

The active ingredient in the commercial workplace urine drug-testing adulterant, Klear, was previously determined to be nitrite ion. Nitrite adulteration compromises the confirmation of some drugs, notably the marijuana metabolite. A previously reported bisulfite step overcomes some nitrite adulteration, but it cannot do so in every case, which leaves the laboratory to report the specimen as not suitable for testing. Unlike many other adulterants, nitrite is found in normal urine at low concentrations. In order to defend a report of nitrite adulteration, it is necessary to provide evidence that the amount of nitrite in a workplace urine specimen could not arise by normal means. The objectives of this study were to identify all sources of nitrite in urine and the range of concentrations associated with these sources and to determine if nitrite adulteration can be supported based upon a quantitative result. The scientific literature was reviewed for internal and external sources of nitrite and their concentration ranges and are reported. The following specimens were obtained and nitrite concentrations measured by a spectrophotometric method: clinical specimens nitrite positive by test strip (< 15 micrograms/mL); specimens culture positive for nitrate-reducing microorganisms (< 36 micrograms/mL); specimens from patients on medications that may metabolize to nitrite (< 6 micrograms/mL); and drug-test specimens, both negative (< 130 micrograms/mL) and others that appeared to be adulterated with nitrite (range 1910-12,200 micrograms/mL, mean 5910). The literature and the nitrite measurements of this study indicate a substantial difference between concentrations from natural sources compared with adulteration. A quantitative measurement of nitrite by a well-structured assay can provide scientifically valid and forensically defensible proof of adulteration with a nitrite-containing substance.

Markedly elevated gamma-glutamyltransferase

Gamma-glutamyltransferase (GGT) is a highly sensitive but poorly specific liver enzyme commonly used to detect hepatobiliary disease and possible alcohol abuse. Isolated elevations of this enzyme may be due to biochemical anomalies rather than the presence of pathology.

Improving ion mass ratio performance at low concentrations in methamphetamine GC-MS assay through internal standard selection

In federally regulated drug testing, laboratories must identify and quantitate drugs and their breakdown products by gas chromatography-mass spectrometry (GC-MS) to a concentration that is at least 60% below the cutoff concentration for reconfirmation purposes. Use of methamphetamine-d5 as an internal standard in routine testing with derivatization by HFBA was found to contribute m/z 91 and 118 ions to the same ions from the nondeuterated methamphetamine in the specimen. This resulted in poor chromatography and occasionally caused the 91/254 and 118/254 ion mass ratios to exceed the +20% acceptance limit established in the calibration process at low concentrations. The analogues methamphetamine-d8 and -d11 were evaluated for contributions to the nondeuterated methamphetamine ion fragments. Methamphetamine-d8 produced m/z 91 and 118 ions, but in less abundance than methamphetamine-d5. Methamphetamine-d11 was found to produce little or no detectable m/z 91 or 118. Replacing methamphetamine-d5 with methamphetamine-d11 eliminates this problem and allows the assay to consistently produce ion mass ratios and acceptable chromatography sufficient for identifying and quantitating methamphetamine at 60% below the 500-ng/mL cutoff concentration.

Pharmacological basis for functional selectivity of partial muscarinic receptor agonists

Muscarinic receptor agonists activate phosphoinositide hydrolysis and adenylate cyclase in Chinese hamster ovary cells transfected with cDNAs encoding the human muscarinic ml and m3 receptors. Whereas carbachol activates similarly both receptor subtypes, 4-[3-chlorophenyl-carbamoyloxy]-2-butynyltrimethyl ammonium chloride (McN-A-343) preferentially activates the m1 subtype over m3, in regard to both phosphoinositide hydrolysis and adenylate cyclase activity. On the other hand, oxotremorine activates phosphoinositide hydrolysis to a similar extent in both cell lines, but it activates preferentially adenylate cyclase in m1 versus m3 receptor expressing cells. Relative to carbachol, both McN-A-343 and oxotremorine activate preferentially phosphoinositide hydrolysis over adenylate cyclase in both cell lines. Prolonged incubation of cells with either carbachol, McN-A-343, or oxotremorine down-regulated the m1 receptors. This was accompanied by a parallel decrease in adenylate cyclase activity, whereas phosphoinositide hydrolysis remained relatively high. Inactivation of the receptors by alkylation with acetylethylcholine mustard, or by blocking with atropine, reduced carbachol-stimulated adenylate cyclase activity more effectively than carbachol-induced phosphoinositide hydrolysis in both m1 and m3 receptor expressing cells. These findings imply that the receptor reserve in these cell lines is greater for phosphoinositide hydrolysis response than for adenylate cyclase response. Yet, the receptor reserve for each of these responses is similar in both m1 and m3 receptor expressing cells. Since the binding affinities of McN-A-343 and of oxotremorine to m1 and m3 receptors are very similar, and since both cell lines contain similar amounts of spare receptors, we propose that the preferential activation of muscarinic m1 over m3 receptor by partial agonists is related to differences in the abilities of the two receptor subtypes to undergo conformational changes following agonist binding. This hypothesis is supported by results showing that the muscarinic m1 but not m3 receptor exhibits two affinity states in a competition binding assay.

Men, women & alcohol: a distinctly unequal & dangerous relationship

This article illustrates how women who abuse alcohol are at greater risk physically, emotionally and socially than their male counterparts. As a result, I recommend that clinical assessment and underwriting of women, who abuse or have the potential to abuse alcohol, change to reflect the increased risks which these women face.

A rapid gas chromatographic method quantitating clozapine in human plasma or serum for the purpose of therapeutic monitoring

A gas chromatographic method using nitrogen-phosphorus detection was developed to quantitate clozapine in plasma or serum. Methyl clonazepam was used as an internal standard. Sample preparation included a single-step extraction with ethyl acetate, which was injected directly onto a wide-bore capillary column. Within-run and total precision, measured as percent coefficient of variation, were determined at low, therapeutic, and high clozapine plasma concentrations. The within-run precision for the low, therapeutic, and high clozapine plasma samples was 5.2, 2.7, and 2.4%, respectively. The total precision for the low, therapeutic, and high clozapine plasma samples was 10.0, 2.6, and 2.0%, respectively. Analytical accuracy was evaluated by comparing quantitative results with those obtained from a reference laboratory. Those samples containing therapeutic or high concentrations agreed within 3%; the sample containing a subtherapeutic concentration differed by 11.9%. The limit of quantitation was determined to be 35 ng/mL, and the upper limit of linearity was 3000 ng/mL. No significant interferences were detected after testing more than two dozen drugs and metabolites.