Real time quantification in plasma of human telomerase reverse transcriptase (hTERT) mRNA in patients with colorectal cancer

Clinical value of perioperative levels of DNA and mRNA in plasma of patients with renal cell carcinoma

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Plasma levels of GAPDH cfDNA might be useful as complementary methods for diagnosis and prognosis of renal cell carcinoma.

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Pre and postoperative levels of GAPDH cfDNA were independently associated with OS in renal cell carcinoma.

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hTERT cfRNA was not a marker useful for diagnosis nor prognosis of renal cell cancer.

Introduction

The current challenge on renal cell carcinoma (RCC) is to finding a non-invasive biomarker for improving their diagnostic and therapeutic management. In the present study, we analyzed the clinical value of plasma levels of cell-free DNA (cfDNA) and RNA (cfRNA) of two genes: glyceraldehyde 3-phosphate-dehydrogenase (GAPDH) and human telomerase reverse transcriptase (hTERT).

Materials and methods

We recruited 82 patients with RCC, and 20 healthy subjects. Using RT-PCR techniques, plasma levels of cfDNA and cfRNA from hTERT and GAPDH genes were quantified pre- and post-operatively, and one year after surgery. Relationships between such plasma levels and clinicopathological features and evolution of disease were analyzed.

Results

Levels of GAPDH cfDNA and cfRNA were significantly higher in patients than in healthy subjects. hTERT cfDNA was detected in plasma from 35% of RCC patients and in none healthy subject. At diagnosis, plasma levels of GAPDH cfDNA were higher in advanced pT and TNM stages, and hTERT cfDNA in patients with 3–4 Fuhrman grade and affected lymph nodes. Levels of cfNAs were not related to the presence of metastasis. Following nephrectomy, GAPDH cfDNA levels dropped, and patients with higher levels before and after nephrectomy, showed lower overall survival (OS). However, Cox's multivariate model did not prove any association of the cfNA levels with progression.

Conclusion

Plasma levels of cfDNA from GADPH and hTERT genes were correlated to tumor diagnosis and progression and, thus, such analyses might help to diagnosis and prognosis of RCC patients.

A Review of GC-Based Analysis of Non-Invasive Biomarkers of Colorectal Cancer and Related Pathways

Colorectal cancer (CRC) is the third most commonly diagnosed cancer in the world. In Europe, it is the second most common cause of cancer-related deaths. With the advent of metabolomics approaches, studies regarding the investigation of metabolite profiles related to CRC have been conducted, aiming to serve as a tool for early diagnosis. In order to provide further information about the current status of this field of research, 21 studies were systematically reviewed, regarding their main findings and analytical aspects. A special focus was given to the employment of matrices obtained non-invasively and the use of gas chromatography as the analytical platform. The relationship between the reported volatile and non-volatile biomarkers and CRC-related metabolic alterations was also explored, demonstrating that many of these metabolites are connected with biochemical pathways proven to be involved in carcinogenesis. The most commonly reported CRC indicators were hydrocarbons, aldehydes, amino acids and short-chain fatty acids. These potential biomarkers can be associated with both human and bacterial pathways and the analysis based on such species has the potential to be applied in the clinical practice as a low-cost screening method.

cfRNAs as biomarkers in oncology - still experimental or applied tool for personalized medicine already?

Currently, the challenges of contemporary oncology are focused mainly on the development of personalized medicine and precise treatment, which could be achieved through the use of molecular biomarkers. One of the biological molecules with great potential are circulating free RNAs (cfRNAs) which are present in various types of body fluids, such as blood, serum, plasma, and saliva. Also, different types of cfRNA particles can be distinguished depending on their length and function: microRNA (miRNA), PIWI-interacting RNA (piRNA), tRNA-derived RNA fragments (tRFs), circular RNA (circRNA), long non-coding RNA (lncRNA), and messenger RNA (mRNA). Moreover, cfRNAs occur in various forms: as a free molecule alone, in membrane vesicles, such as exosomes, or in complexes with proteins and lipids. One of the modern approaches for monitoring patient's condition is a "liquid biopsy" that provides a non-invasive and easily available source of circulating RNAs. Both the presence of specific cfRNA types as well as their concentration are dependent on many factors including cancer type or even reaction to treatment. Despite the possibility of using circulating free RNAs as biomarkers, there is still a lack of validated diagnostic panels, defined protocols for sampling, storing as well as detection methods. In this work we examine different types of cfRNAs, evaluate them as possible biomarkers, and analyze methods of their detection. We believe that further research on cfRNA and defining diagnostic panels could lead to better and faster cancer identification and improve treatment monitoring.

A molecular multi-gene classifier for disease diagnostics

Despite its early promise as a diagnostic and prognostic tool, gene expression profiling remains cost-prohibitive and challenging to implement in a clinical setting. Here, we introduce a molecular computation strategy for analysing the information contained in complex gene expression signatures without the need for costly instrumentation. Our workflow begins by training a computational classifier on labelled gene expression data. This in silico classifier is then realized at the molecular level to enable expression analysis and classification of previously uncharacterized samples. Classification occurs through a series of molecular interactions between RNA inputs and engineered DNA probes designed to differentially weigh each input according to its importance. We validate our technology with two applications: a classifier for early cancer diagnostics and a classifier for differentiating viral and bacterial respiratory infections based on host gene expression. Together, our results demonstrate a general and modular framework for low-cost gene expression analysis.

The predictive and prognostic potential of plasma telomerase reverse transcriptase (TERT) RNA in rectal cancer patients

BACKGROUND

Preoperative chemoradiotherapy (CRT) followed by surgery is the standard care for locally advanced rectal cancer, but tumour response to CRT and disease outcome are variable. The current study aimed to investigate the effectiveness of plasma telomerase reverse transcriptase (TERT) levels in predicting tumour response and clinical outcome.

METHODS

176 rectal cancer patients were included. Plasma samples were collected at baseline (before CRT=T0), 2 weeks after CRT was initiated (T1), post-CRT and before surgery (T2), and 4-8 months after surgery (T3) time points. Plasma TERT mRNA levels and total cell-free RNA were determined using real-time PCR.

RESULTS

Plasma levels of TERT were significantly lower at T2 (P<0.0001) in responders than in non-responders. Post-CRT TERT levels and the differences between pre- and post-CRT TERT levels independently predicted tumour response, and the prediction model had an area under curve of 0.80 (95% confidence interval (CI) 0.73-0.87). Multiple analysis demonstrated that patients with detectable TERT levels at T2 and T3 time points had a risk of disease progression 2.13 (95% CI 1.10-4.11)-fold and 4.55 (95% CI 1.48-13.95)-fold higher, respectively, than those with undetectable plasma TERT levels.

CONCLUSIONS

Plasma TERT levels are independent markers of tumour response and are prognostic of disease progression in rectal cancer patients who undergo neoadjuvant therapy.

The role of cell-free DNA in predicting colorectal cancer prognosis

Colorectal cancer is a cancer of the digestive system with poor prognosis. Cell-free DNA has received much attention with its unique predominance, especially in colorectal cancer. Areas covered: This study has summarized recent advancements and challenges regarding cell-free DNA in predicting CRC prognosis. Furthermore, the authors make predictions on the potential developments concerning cell-free DNA in future prognosis prediction techniques. Expert commentary: Cell-free DNA has the value of predicting CRC prognosis as an important biomarke. Further clinical trials should be performed to promote translating cell-free DNA into clinical applications.

The combination of circulating long noncoding RNAs AK001058, INHBA-AS1, MIR4435-2HG, and CEBPA-AS1 fragments in plasma serve as diagnostic markers for gastric cancer

Background

Suitable diagnostic markers for cancers are urgently required in clinical practice. Long non-coding RNAs, which have been reported in many cancer types, are a potential new class of biomarkers for tumor diagnosis.

Results

Five lncRNAs, including AK001058, INHBA-AS1, MIR4435-2HG, UCA1 and CEBPA-AS1 were validated to be increased in gastric cancer tissues. Furthermore, we found that plasma level of these five lncRNAs were significantly higher in gastric cancer patients compared with normal controls. By receiver operating characteristic analysis, we found that the combination of plasma lncRNAs with the area under the curve up to 0.921, including AK001058, INHBA-AS1, MIR4435-2HG, and CEBPA-AS1, is a better indicator of gastric cancer than their individual levels or other lncRNA combinations. Simultaneously, we found that the expression levels of a series of MIR4435-2HG fragments are different in gastric cancer plasma samples, but most of them higher than that in healthy control plasma samples.

Materials and Methods

LncRNA gene expression profiles were analyzed in two pairs of human gastric cancer and adjacent non-tumor tissues by microarray analysis. Nine gastric cancer-associated lncRNAs were selected and assessed by quantitative real-time polymerase chain reaction in gastric tissues, and 5 of them were further analyzed in gastric cancer patients’ plasma.

Conclusions

Our results demonstrate that certain lncRNAs, such as AK001058, INHBA-AS1, MIR4435-2HG, and CEBPA-AS1, are enriched in human gastric cancer tissues and significantly elevated in the plasma of patients with gastric cancer. These findings indicate that the combination of these four lncRNAs might be used as diagnostic or prognostic markers for gastric cancer patients.

Potential clinical significance of perioperative levels of mRNA in plasma from patients with cancer of the larynx or hypopharynx

BACKGROUND

The use of plasma as a "liquid biopsy" has gained increasing attention. The purpose of the present study was to evaluate the diagnostic and prognostic utility of the perioperative detection and quantitation of mRNAs encoding human telomerase reverse transcriptase (hTERT) and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) in plasma from patients with cancer of the larynx or hypopharynx.

METHODS

We recruited 47 patients with laryngeal cancer and 2 patients with hypopharyngeal cancer, plus 27 healthy subjects. A blood sample was taken from each patient before and after surgical resection of the tumor. We quantified hTERT mRNA and GAPDH mRNA in plasma by real-time polymerase chain reaction (PCR).

RESULTS

Detection of hTERT mRNA before surgery had diagnostic value (sensitivity, 22%; specificity, 100%). Detection was more frequent in patients with supraglottic tumors than glottic tumors (p = .02) and was related to subsequent recurrence (p = .02). Preoperative levels of hTERT mRNA in plasma were higher in patients with subsequent recurrence (p = .046) and/or metastases (p = .047). The disease-free survival (DFS) and overall survival (OS) of patients with plasma samples positive for hTERT mRNA was poorer than that of patients with negative samples. Mean levels of plasma GAPDH mRNA in untreated patients were higher than in healthy subjects (p < .001).

CONCLUSION

Detection and quantitation of hTERT and GAPDH mRNA in patients' plasma might be clinically significant in cases of laryngeal and hypopharyngeal cancer. © 2017 Wiley Periodicals, Inc. Head Neck 39: 647-655, 2017.

Circulating nucleic acids: An analysis of their occurrence in malignancies

Through a regulated or fortuitous phenomenon, small portions of cell nucleic acids are thrown into circulation. Since the discovery of these circulating nucleic acids (CNAs) in 1948, numerous studies have been published to elucidate their clinical implications in multifarious diseases. Scientists have now discovered disease-specific genetic aberrations, such as mutations, microsatellite alterations, epigenetic modulations (including aberrant methylation), as well as viral DNA/RNA from nucleic acids in plasma and serum. CNAs have become increasingly popular due to their potential for use as a liquid biopsy, which is a tool for non-invasive diagnosis and monitoring of diseases, such as cancer, stroke, trauma, myocardial infarction, autoimmune disorders, and pregnancy-associated complications. While the diagnostic potential of CNAs has been investigated extensively, there is a paucity of understanding of their pathophysiological functions. Are these CNAs part of the cell's regular framework of functioning? Or do they act as molecular players in disease initiation and progression? The aim of this review is to investigate the origins and functions of the circulating cell-free nucleic acids in the plasma and serum of patients with various malignancies, and propose areas of study, which may elucidate the novel underlying mechanisms that are functioning during cancer initiation/progression.

Expression of two basic mRNA biomarkers in peripheral blood of patients with non-small cell lung cancer detected by real-time rt-PCR, individually and simultaneously

Introduction: Although extensive research has been conducted on lung cancer markers, a singular clinically applicable marker has not been found yet. The objective of this study was to evaluate the sensitivity and the specificity of carcinoembryonic antigen (CEA) mRNA and lung-specific X protein (LUNX) mRNA biomarkers in peripheral blood to detect lung cancer individually and simultaneously. Methods: Thirty patients affected by lung cancer and 30 healthy individuals were studied in this research. Three vials of cDNA were made from each sample after taking peripheral blood samples and extracting total RNA. Each sample was examined by the real-time RT-PCR technique. The result from each vial was then compared with the sensitivity of overall marker. Results: The CEA mRNA was positive in 24 out of 30 lung cancer patients. Hence, its sensitivity was determined at 80%, differing significantly from that observed in healthy individuals, where 11 positive cases were seen. The overall sensitivity of this marker was significantly associated with positivity in vials 2 and 3 but not in vial 1. The LUNX mRNA was positive in 21 out of 30 patients, indicating 70% sensitivity. This finding significantly differed from that in healthy individuals. The overall sensitivity of this marker was significantly associated with positivity in vials 1 and 3, but not in vial 2. In 93.3% of the patients, at least one positive marker was observed. Conclusion: The mentioned mRNA could be suggested as sensitive and specific markers in peripheral blood for primary diagnosis of lung cancer.

Colorectal Cancer Biomarkers: Where Are We Now?

Colorectal cancer is one of the major causes of cancer-related death in the Western world. Patient survival is highly dependent on the tumor stage at the time of diagnosis. Reduced sensitivity to chemotherapy is still a major obstacle in effective treatment of advanced disease. Due to the fact that colorectal cancer is mostly asymptomatic until it progresses to advanced stages, the implementation of screening programs aimed at early detection is essential to reduce incidence and mortality rates. Current screening and diagnostic methods range from semi-invasive procedures such as colonoscopy to noninvasive stool-based tests. The combination of the absence of symptoms, the semi-invasive nature of currently used methods, and the suboptimal accuracy of fecal blood tests results in colorectal cancer diagnosis at advanced stages in a significant number of individuals. Alterations in gene expression leading to colorectal carcinogenesis are reflected in dysregulated levels of nucleic acids and proteins, which can be used for the development of novel, minimally invasive molecular biomarkers. The purpose of this review is to discuss the commercially available colorectal cancer molecular diagnostic methods as well as to highlight some of the new candidate predictive and prognostic molecular markers for tumor, stool, and blood samples.

Phase I Study of Lapatinib and Pemetrexed in the Second-Line Treatment of Advanced or Metastatic Non-Small-Cell Lung Cancer With Assessment of Circulating Cell Free Thymidylate Synthase RNA as a Potential Biomarker

INTRODUCTION

Lapatinib is a dual tyrosine kinase inhibitor that targets epidermal growth factor receptor and HER2. We report on a dose-escalation study of lapatinib combined with pemetrexed in second-line treatment to evaluate the safety and efficacy in advanced or metastatic non-small-cell lung cancer (NSCLC) and an exploratory study in which circulating cell-free thymidylate synthase ribonucleic acid (cfTSmRNA) was measured in all patients and compared with clinical benefit.

PATIENTS AND METHODS

Eligible patients had stage IIIB or IV NSCLC after 1 previous line of chemotherapy and an Eastern Cooperative Oncology Group performance status of 0 to 2. Three dose levels (DLs) of lapatinib (daily)/pemetrexed (every 21 days) were evaluated: DL0, 1250 mg/400 mg; DL1, 1250 mg/500 mg; and DL2, 1500 mg/500 mg, respectively. The primary outcome was identification of the optimal treatment regimen.

RESULTS

Eighteen patients were treated (DL0: n = 4; DL1: n = 8; DL2: n = 6). The most common adverse events (any grade) were diarrhea (61%), rash (44%), nausea (33%), anemia, and fatigue (both 28%). DL1 was determined as optimal after 3 dose-limiting toxicities (DLTs) during the first cycle of DL2 (Grade 3 diarrhea and mucositis, Grade 4 lymphocytopenia); no other DLTs were observed. Partial response was detected in 4 patients. cfTSmRNA was at the limit of detection and was not measurable in all patients. Nonsignificant trends were observed, suggesting that higher levels of cfTSmRNA are associated with poorer outcome. Confirmatory studies are required.

CONCLUSION

Lapatinib and pemetrexed was well tolerated, and data suggest a similar response rate to pemetrexed monotherapy.

Cell-free nucleic acids as noninvasive biomarkers for colorectal cancer detection

Cell-free nucleic acids (CFNA) have been reported by several authors in blood, stool, and urine of patients with colorectal cancer (CRC). These genetic biomarkers can be an indication of neoplastic colorectal epithelial cells, and can thus potentially be used as noninvasive tests for the detection of the disease in CRC patients and monitor their staging, without the need to use heavier and invasive tools. In a number of test-trials, these genetic tests have shown the advantage of non-invasiveness, making them well accepted by most of the patients, without major side effects. They have also shown a promising sensitivity and specificity in the detection of malignant and premalignant neoplasms. Moreover, costs for performing such tests are very low. Several studies reported and confirmed the proof of the principle for these genetic tests for screening, diagnosis, and prognosis; the main challenge of translating this approach from research to clinical laboratory is the validation from large and long-term randomized trials to prove sustainable high sensitivity and specificity. In this paper, we present a review on the noninvasive genetics biomarkers for CRC detection described in the literature and the challenges that can be encountered for validation processes.

Consensus on the Prevention, Screening, Early Diagnosis and Treatment of Colorectal Tumors in China: Chinese Society of Gastroenterology, October 14-15, 2011, Shanghai, China

BACKGROUND

Colorectal cancer (CRC) is steadily increasing in China. Colorectal adenoma (CRA) is the most important precancerous disease of CRC. Screening for colorectal tumors can aid early diagnosis. Advances in endoscopic mucosal resection and endoscopic submucosal dissection can aid the early treatment of colorectal tumors. Furthermore, because of high risk of recurrence after removal of adenomas under endoscopy, factors contributing to recurrence, the follow-up mode and the interval established, and the feasibility of application and the time of various chemical preventions should be concerned. However, a relevant consensus on the screening, early diagnosis and treatment, and prevention of colorectal tumors in China is lacking.

SUMMARY

The consensus recommendations include epidemiology, pathology, screening, early diagnosis, endoscopic treatment, monitoring and follow-up, and chemoprevention of colorectal tumors in China.

KEY MESSAGE

This is the first consensus on the prevention, screening, early diagnosis and treatment of CRA and CRC in China based on evidence in the literature and on local data.

PRACTICAL IMPLICATIONS

Through reviewing the literature, regional data and passing the consensus by an anonymous vote, gastroenterology experts from all over China launch the consensus recommendations in Shanghai. The incidence and mortality of CRC in China has increased, and the incidence or detection rate of CRA has increased rapidly. Screening for colorectal tumors should be performed at age 50-74 years. Preliminary screening should be undertaken to find persons at high risk, followed by colonoscopy. A screening cycle of 3 years is recommended for persistent interventions. Opportunistic screening is a mode suitable for the current healthcare system and national situation. Colonoscopy combined with pathological examination is the standard method for the diagnosis of colorectal tumors. CRA removal under endoscopy can prevent CRC to some extent, but CRA has an obvious recurrence trend. The follow-up interval after the removal or surgery of colorectal tumors should be different with lesions. Primary prevention of CRA includes improved diet with more fiber, supplements containing calcium and vitamin D, supplements containing folic acid for those with low hemoglobin levels, and cessation of tobacco smoking. Non-steroidal anti-inflammatory drugs and selective cyclooxygenase-2 inhibitors have been recognized to prevent recurrence after adenoma removal.

Circulating nucleic acids in plasma and serum (CNAPS): applications in oncology

The presence of small amounts of circulating nucleic acids in plasma and serum (CNAPS) is not a new finding. The verification that such amounts are significantly increased in cancer patients, and that CNAPS might carry a variety of genetic and epigenetic alterations related to cancer development and progression, has aroused great interest in the scientific community in the last decades. Such alterations potentially reflect changes that occur during carcinogenesis, and include DNA mutations, loss of heterozygosity, viral genomic integration, disruption of microRNA, hypermethylation of tumor suppressor genes, and changes in the mitochondrial DNA. These findings have led to many efforts toward the implementation of new clinical biomarkers based on CNAPS analysis. In the present article, we review the main findings related to the utility of CNAPS analysis for early diagnosis, prognosis, and monitoring of cancer, most of which appear promising. However, due to the lack of harmonization of laboratory techniques, the heterogeneity of disease progression, and the small number of recruited patients in most of those studies, there has been a poor translation of basic research into clinical practice. In addition, many aspects remain unknown, such as the release mechanisms of cell-free nucleic acids, their biological function, and the way by which they circulate in the bloodstream. It is therefore expected that in the coming years, an improved understanding of the relationship between CNAPS and the molecular biology of cancer will lead to better diagnosis, management, and treatment.

Improved real-time rt-PCR assays of two colorectal cancer peripheral blood mRNA biomarkers: a pilot study

BACKGROUND

Efficient screening for detection of colorectal cancer (CRC) at earlier stages reduces its mortality. The purpose of this study was to investigate expression of carcinoembryonic antigen (CEA) and human telomerase reverse transcriptase (hTERT) mRNA in peripheral blood of CRC patients and to present strategies for early detection screen test.

METHODS

Twenty seven patients in non-metastatic stage and 27 healthy individuals were studied. Expression of CEA, hTERT mRNA and 18srRNA (18s subunit of ribosomal RNA, as reference gene) were determined based on real-time RT-PCR on 3 µg of total RNA from blood in 3 separate vials (1 µg per vial).

RESULTS

Positive expression rate of CEA mRNA (78%) and hTERT mRNA (81%) were higher in patient group (P<0.001). These rates were meaningfully higher than the results of individual vials containing only 1 µg of total RNA. Difference between Ct values of markers with 18srRNA ΔCt) was higher in healthy group than patient one. Therefore, a ΔCt cut-off value was determined for distinguishing between true- and false-positive results. Concurrent expression of both markers was found in 67% of the patients, which was higher than healthy cases (11%). Combination of concurrent marker expression with cut-off point strategy increased specificity to 100%.

CONCLUSION

These results showed that concurrent evaluation of marker expression and performing the test on 3 µg of samples in 3 separate vials may increase specificity and sensitivity of real-time RT-PCR for early detection of non-metastatic CRC. However, more investigations with larger numbers of samples are needed to verify these results.

Quantitation of cell-free DNA and RNA in plasma during tumor progression in rats

BACKGROUND

To clarify the implications of cell-free nucleic acids (cfNA) in the plasma in neoplastic disease, it is necessary to determine the kinetics of their release into the circulation.

METHODS

To quantify non-tumor and tumor DNA and RNA in the plasma of tumor-bearing rats and to correlate such levels with tumor progression, we injected DHD/K12-PROb colon cancer cells subcutaneously into syngenic BD-IX rats. Rats were sacrificed and their plasma was analyzed from the first to the eleventh week after inoculation.

RESULTS

The release of large amounts of non-tumor DNA into plasma was related to tumor development from its early stages. Tumor-specific DNA was detected in 33% of tumor-bearing rats, starting from the first week after inoculation and at an increasing frequency thereafter. Animals that were positive for tumor DNA in the plasma had larger tumors than those that were negative (p = 0.0006). However, the appearance of both mutated and non-mutated DNA fluctuated with time and levels of both were scattered among individuals in each group. The release of non-tumor mRNA was unaffected by tumor progression and we did not detect mutated RNA sequences in any animals.

CONCLUSIONS

The release of normal and tumor cfDNA into plasma appeared to be related to individual-specific factors. The contribution of tumor DNA to the elevated levels of plasma DNA was intermittent. The release of RNA into plasma during cancer progression appeared to be an even more selective and elusive phenomenon than that of DNA.

Noninvasive screening tests for colorectal cancer

BACKGROUND

Identifying an accurate, reliable, affordable, and acceptable noninvasive screening test for colorectal cancer (CRC) would greatly facilitate population screening.

METHODS

Published literature from 2000 through February 2012 on noninvasive CRC screening tests was identified, reviewed, and summarized.

RESULTS

The highest quality evidence for noninvasive screening exists for guaiac-based fecal occult blood tests (gFOBTs), for which the CRC-specific incidence and mortality reductions are modest. Fecal immunochemical tests (FITs) offer better sensitivity and comparable specificity. Cross-sectional studies comparing gFOBTs and FITs suggest that FITs provide higher detection of advanced neoplasia. Modeling studies favor FITs over gFOBTs with respect to effectiveness and cost-effectiveness. A myriad of studies report the performance of fecal-based and blood-based genetic and protein-based biomarkers; the studies differ in patient population assembled, marker selection, and assay methods. Several markers and panels of markers are promising, although nearly all studies focus on new markers and/or assay methods on small sets of referred patients rather than validating markers using optimal assays in a screening setting.

CONCLUSION

In the absence of long-term randomized trials, adoption of the noninvasive tests will require cross-sectional data on test characteristics obtained from the screening setting, where CRC prevalence is low and the full spectrum of colorectal findings exists, along with estimates of cumulative risks, benefits, and cost-effectiveness. Test adoption will ultimately depend on test characteristics, availability, affordability, and user appeal. There is no noninvasive substitute for the currently recommended screening tests. FITs should replace gFOBTs wherever gFOBTs are used for screening.

Circulating MACC1 transcripts in colorectal cancer patient plasma predict metastasis and prognosis

Background

Metastasis is the most frequent cause of treatment failure and death in colorectal cancer. Early detection of tumors and metastases is crucial for improving treatment strategies and patient outcome. Development of reliable biomarkers and simple tests routinely applicable in the clinic for detection, prognostication, and therapy monitoring is of special interest. We recently identified the novel gene Metastasis-Associated in Colon Cancer 1 (MACC1), a key regulator of the HGF/Met-pathway. MACC1 is a strong prognostic biomarker for colon cancer metastasis and allows identification of high-risk subjects in early stages, when determined in patients’ primary tumors. To overcome the limitation of a restricted number of molecular analyses in tumor tissue, the establishment of a non-invasive blood test for early identification of high-risk cancer patients, for monitoring disease course and therapy response is strongly needed.

Methodology/Principal Findings

For the first time, we describe a non-invasive assay for quantification of circulating MACC1 transcripts in blood of more than 300 colorectal cancer patients. MACC1 transcript levels are increased in all disease stages of the cancer patients compared to tumor-free volunteers. Highest MACC1 levels were determined in individuals with metastases (all P<0.05). Importantly, high MACC1 levels correlate with unfavorable survival (P<.0001). Combining MACC1 with circulating transcripts of the metastasis gene S100A4, a transcriptional target of the Wnt/β-catenin-pathway, improves survival prediction for newly diagnosed cancer patients.

Conclusion/Significance

This blood-based assay for circulating MACC1 transcripts, which can be quantitated on a routine basis, is clinically applicable for diagnosis, prognosis, and therapeutic monitoring of cancer patients. Here we demonstrate the diagnostic and prognostic value of circulating MACC1 transcripts in patient plasma for metastasis and survival. Since MACC1 represents a promising target for anti-metastatic therapies, circulating MACC1 transcripts may prove to be an ideal read-out for monitoring therapeutic response of future interventions targeting MACC1-induced metastasis in cancer patients.

Cell-free circulating plasma hTERT mRNA is a useful marker for prostate cancer diagnosis and is associated with poor prognosis tumor characteristics

Background

Serum prostate-specific antigen (PSA) is the most widely used marker for diagnosing prostate cancer (PCa). It lacks specificity and predictive value, resulting in inaccurate diagnoses and overtreatment of the disease. The aim of this study was to assess the usefulness of plasma telomerase reverse transcriptase (hTERT) mRNA as a diagnostic and prognostic tool for PCa and its association with clinicopathological parameters of tumors.

Principal Findings

Plasma hTERT mRNA levels were determined by qRT-PCR in 105 consecutive patients with elevated PSA levels and in 68 healthy volunteers. The diagnostic accuracy, the efficacy as a prognostic factor of biochemical recurrence and the association with tumor clinicopathological parameters of plasma hTERT mRNA and serum PSA tests were determined using univariate and multivariate analyses. The results show that plasma hTERT mRNA is a non-invasive biomarker for PCa diagnosis that shows higher sensitivity (85% vs. 83%), specificity (90% vs. 47%), positive predictive value (83% vs. 56%), and negative predictive value (92% vs. 77%) than serum PSA. Plasma hTERT mRNA is significantly associated with poor prognosis tumor clinicopathological parameters and is a significant independent predictor of PCa (p<0.0001). Univariate analysis identified plasma hTERT mRNA (but not serum PSA) as a significant prognostic factor of biochemical recurrence. Plasma hTERT mRNA Kaplan-Meier curves confirmed the significant differences between groups and patients with higher levels than the cut-off value showed diminished recurrence-free survival (p = 0.004), whereas no differences were observed with serum PSA (p = 0.38). Multivariate analysis indicated that plasma hTERT mRNA (but not serum PSA) and stage were significantly associated with biochemical recurrence.

Conclusions

Overall, these findings indicate that hTERT mRNA is a useful non-invasive tumor marker for the molecular diagnosis of PCa, affording a greater diagnostic and prognostic accuracy than the PSA assay and may be of relevance in the follow-up of the disease.

Plasma hTERT mRNA discriminates between clinically localized and locally advanced disease and is a predictor of recurrence in prostate cancer patients

INTRODUCTION

Since the introduction of prostate-specific antigen (PSA) testing, new prostate cancer (PCa) patients are diagnosed earlier and most have localized and locally advanced disease. Current diagnosis methods lack specificity and sensitivity, leading to overdiagnosis and overtreatment of patients with low-risk organ-confined localized disease. Therefore, new non-invasive molecular tools are needed to discriminate between localized and locally advanced disease.

METHODS

Plasma telomerase reverse transcriptase (hTERT) mRNA levels were determined by qRT-PCR in 49 patients with localized and locally advanced PCa. Diagnostic accuracy and efficacy as a prognostic factor of biochemical recurrence of plasma hTERT mRNA were determined using univariate and multivariate analyses and compared with conventional tumor markers.

RESULTS

Patients with locally advanced disease had significantly (p < 0.05) higher plasma hTERT mRNA and serum PSA levels than those with localized disease. Plasma hTERT mRNA test showed lower sensitivity (83% vs. 100%), higher specificity (73% vs. 43%), AUC ROC curve (0.911 vs. 0.757), and positive likelihood ratios (6.17 vs. 1.76) than the PSA assay in discriminating between localized and locally advanced disease. At multivariate analysis, plasma hTERT mRNA levels and age but not PSA showed a positive trend (p = 0.05) in the risk of locally advanced PCa. On univariate analysis, plasma hTERT mRNA and serum PSA were identified as significant prognostic factors of biochemical recurrence. Using ROC curves and the appropriate cutoff, both tests showed high sensitivity (85%) and specificity (72%). Kaplan-Meier curves confirmed the significant differences between the groups and patients with higher levels than the cutoff value showed diminished recurrence-free survival (p < 0.05). At multivariate analysis, Gleason score and PSA were the strongest factors associated with biochemical recurrence (p < 0.05), whereas hTERT mRNA did not reach statistical significance, although a positive trend was observed (p = 0.09).

CONCLUSION

Plasma hTERT mRNA quantification can be both a useful non-invasive tumor marker for discriminating between localized and locally advanced PCa, as well as a prognostic factor of recurrence at the molecular level.

Screening for colorectal cancer

March is national colorectal cancer awareness month. It is estimated that as many as 60% of colorectal cancer deaths could be prevented if all men and women aged 50 years or older were screened routinely. In 2000, Katie Couric's televised colonoscopy led to a 20% increase in screening colonoscopies across America, a stunning rise called the "Katie Couric Effect". This event demonstrated how celebrity endorsement affects health behavior. Currently, discussion is ongoing about the optimal strategy for CRC screening, particularly the costs of screening colonoscopy. The current CRC screening guidelines are summarized in Table 2. Debates over the optimum CRC screening test continue in the face of evidence that 22 million Americans aged 50 to 75 years are not screened for CRC by any modality and 25,000 of those lives may have been saved if they had been screened for CRC. It is clear that improving screening rates and reducing disparities in underscreened communities and population subgroups could further reduce colorectal cancer morbidity and mortality. National Institutes of Health consensus identified the following priority areas to enhance the use and quality of colorectal cancer screening: Eliminate financial barriers to colorectal cancer screening and appropriate follow-up of positive results of colorectal cancer screening. Develop systems to ensure the high quality of colorectal cancer screening programs. Conduct studies to determine the comparative effectiveness of the various colorectal cancer screening methods in usual practice settings. Encouraging population adherence to screening tests and allowing patients to select the tests they prefer may do more good (as long as they choose something) than whatever procedure is chosen by the medical profession as the preferred test.

Molecular tests for colorectal cancer screening

Detecting and removing high-risk adenomas and early colorectal cancer (CRC) can reduce mortality of this disease. The noninvasive fecal occult blood test (FOBT; guaiac-based or immunochemical) is widely used in screening programs and although effective, it leaves room for improvement in terms of test accuracy. Molecular tests are expected to be more sensitive, specific and informative than current detection tests, and are promising future tools for CRC screening. This review provides an overview of the performances of DNA, RNA, and protein markers for CRC detection in stool and blood. Most emphasis currently is on DNA and protein markers. Among DNA markers there is trend to move away from mutation markers in favor of methylation markers. The recent boost in proteomics research leads to many new candidate protein markers. Usually in small series, some markers show better performance than the present FOBT. Evaluation in large well-controlled randomized trials is the next step needed to take molecular markers for CRC screening to the next level and warrant implementation in a screening setting.

Diagnostic and prognostic value of metastasis inducer S100A4 transcripts in plasma of colon, rectal, and gastric cancer patients

Early detection of tumors and metastases is critical for improving treatment strategies and patient outcomes. The development of molecular markers and simple tests that are clinically applicable for detection, prognostication, and therapy monitoring is strongly needed. The gene S100A4 has long been known to act as a metastasis inducer. High S100A4 levels in the primary tumor are prognostic for metachronous metastasis and correlate with reduced patient survival. We provide, for the first time, a plasma-based assay for transcript quantification of S100A4 in gastrointestinal patients' plasma. We conducted a study to define the diagnostic and prognostic power of S100A4 transcripts using 466 plasma samples from colon, rectal, and gastric cancer patients. Plasma was separated, RNA was isolated, and S100A4 mRNA was determined by quantitative RT-PCR. S100A4 transcripts were increased in cancer patients of each entity (P < 0.0001) and all disease stages (P < 0.05), compared with tumor-free volunteers (sensitivities of 96%, 74%, and 90% and specificities of 59%, 82%, and 71%, for colon, rectal, and gastric cancer patients, respectively). Prospectively analyzed follow-up patients who later experienced metastasis showed higher S100A4 levels than follow-up patients without metastasis. Disease-free survival was decreased in high S100A4-expressing follow-up colorectal cancer patients (P = 0.013). In summary, we developed a method for quantitative S100A4 transcript determination in plasma that allows clinical application routinely. We demonstrated the diagnostic and prognostic potential of this method for early defining cancer staging and patients' risk for metastasis.

Telomerase activity determined by conventional telomeric repeat amplification protocol and reverse transcriptase‐polymerase chain reaction assay in ovarian lesions: A comparison of assays

OBJECTIVE

Telomerase is capable of restoring telomeric sequence lost during replication. No or low levels of telomerase activity are present in normal somatic cells, whereas up to 85-90% of all cancer cells express telomerase activity, suggesting telomerase as a possible tumor marker. The catalytic subunit, hTERT, correlates with the activity of the enzyme.

MATERIAL AND METHODS

Telomerase activity in ovarian tissue was measured by the functional telomeric repeat amplification protocol (TRAP)eze assay, and a quantitative reverse-transcriptase-polymerase chain reaction (RT-PCR) assay measuring the expression of the telomerase catalytic subunit, hTERT.

RESULTS

A weakly positive correlation was found between telomerase activity and severity of ovarian disease using the results of the TRAP assay, compared to a strongly positive correlation considering the results obtained in the RT-PCR assay. A statistically significant difference between the benign and borderline groups was present using the RT-PCR assay, allowing for screening for both borderline and primary malignant conditions with a specificity of 97% and a sensitivity of 68%. No significant statistical difference was found between telomerase activity in benign and borderline conditions when using the TRAP assay. When screening for primary malignancy, the specificity and sensitivity rates were 94% and 21%, respectively.

CONCLUSIONS

The RT-PCR assay allowed discrimination between benign and borderline and malignant cases, and thereby proved superior to the TRAP assay, which could not discriminate the benign cases from the borderline cases. This suggests that the RT-PCR assay may be useful in screening for both borderline and primary malignancy in ovarian lesions.

Detection of peripheral blood human telomerase reverse transcriptase mRNA in colorectal cancer with real-time fluorescent quantitative RT-PCR and its clinical significance

AIM: To establish a real-time fluorescent quantitative reverse transcriptase polymerase chain reaction (RT-PCR) system for determining the expression of human telomerase reverse transcriptase (hTERT) mRNA in colorectal cancer (CRC), and to evaluate their diagnostic value for micrometastasis of CRC.

METHODS: The expression of hTERT mRNA in 53 CRC patients and 21 healthy subjects was determined using real-time fluorescent quantitative RT-PCR. Correlations between their expression and clinical pathological characteristics of CRC were analyzed. Receiver operating characteristic curve (ROC curve) was used to evaluate the diagnostic value for micrometastasis of CRC.

RESULTS: The expression levels of peripheral blood hTERT mRNA were significantly higher in CRC patients than in the normal controls (t′ = 7.953, P < 0.05), and their expressions were correlated with lymph node metastasis, hematogenous metastasis and TNM staging of CRC (t′/t = 2.334, 2.149, 2.460, all P < 0.05). The area under ROC curve of hTERT mRNA in diagnosing CRC was 0.91, and the cutoff value was Ct≤32.

CONCLUSION: Real-time fluorescent quantitative RT-PCR has an advantage of giving the quantitative expression of hTERT mRNA compared with the traditional PCR which was only applied to the qualitative expression. Peripheral blood hTERT mRNA is a novel and excellent marker for micrometastasis of CRC.

Establishment of a new method, transcription-reverse transcription concerted reaction, for detection of plasma hnRNP B1 mRNA, a biomarker of lung cancer

PURPOSE

Development of an early detection marker is one of the most important strategies for improving overall prognosis in lung cancer patients. We previously reported that hnRNP B1--an RNA binding protein--is overexpressed in lung cancer tissue from the early stage of cancer, and found that hnRNP B1 mRNA is detectable in the plasma of lung cancer patients using real-time RT-PCR. The purpose of this study was to establish a quick and simple method for detecting plasma hnRNP B1mRNA for use in screening for lung cancer.

METHODS

TRC, a homogenous method for fluorescence real-time monitoring of isothermal RNA amplification using intercalation activating fluorescence DNA probe, was used to detect plasma hnRNP B1 mRNA.

RESULTS

The detection limit of hnRNP B1 mRNA by TRC using synthetic control RNA or total RNA derived from a lung cancer cell line was 25 or 8.65 x 10(2) copies, respectively. Using total RNA extracted from 600 mul of plasma, we detected hnRNP B1 mRNA in 39.1% (9/23) of lung cancer patients, with levels ranging from 1.9 to 19,045.5 copies/100 ng RNA, and in 5.2% (5/97) of healthy volunteers. Copy numbers were not associated with age, gender, smoking status, or histological type of cancer. TRC could detect 10(3) copies of hnRNP B1 mRNA in 10 min.

CONCLUSION

Detection of plasma hnRNP B1 mRNA by TRC is a quick, easy, and non-invasive method suitable for lung cancer screening.

Real-time PCR quantification of human telomerase reverse transcriptase (hTERT) in colorectal cancer

AIMS

Human telomerase reverse transcriptase (hTERT) is believed to a reliable marker for telomerase activity. The expression of telomerase activity has not been investigated in a consecutive series of patients with colorectal adenocarcinoma in North Queensland. The objective of this study was to evaluate the significance of hTERT mRNA expression in colorectal adenocarcinoma in North Queensland.

METHODS

Matched samples of tumour and adjacent non-tumorous mucosa samples from 53 colorectal carcinomas and nine colorectal adenomas were collected. In all these samples, RNA was extracted and then transcribed to cDNA. Real-time polymerase chain reaction (RT-PCR) was used to quantitate expression the level of hTERT mRNA. The findings were correlated with the clinicopathological features of patients with these tumours prospectively collected into a computerised database.

RESULTS

hTERT mRNA was expressed in all tumour samples. The level of expression in the colorectal adenocarcinomas was significantly higher than the corresponding non-tumorous mucosa (p = 0.009, t-test). The level of expression in the adenocarcinomas was slightly higher than those of adenomas, but the difference was not statistically significant. A higher level of hTERT expression was often noted in the adenocarcinomas arising from the left colon and rectum when compared with those from the right colon (p = 0.029).

CONCLUSIONS

Colorectal adenocarcinoma revealed expression of telomerase hTERT mRNA, which was detected quantitatively by real-time PCR. hTERT could be a potential biomarker for colorectal cancer. The difference between proximal and distal colorectum in hTERT expression could account for their known different clinical behaviour.

Blood markers for early detection of colorectal cancer: a systematic review

BACKGROUND

Despite different available methods for colorectal cancer (CRC) screening and their proven benefits, morbidity, and mortality of this malignancy are still high, partly due to low compliance with screening. Minimally invasive tests based on the analysis of blood specimens may overcome this problem. The purpose of this review was to give an overview of published studies on blood markers aimed at the early detection of CRC and to summarize their performance characteristics.

METHOD

The PUBMED database was searched for relevant studies published until June 2006. Only studies with more than 20 cases and more than 20 controls were included. Information on the markers under study, on the underlying study populations, and on performance characteristics was extracted. Special attention was given to performance characteristics by tumor stage.

RESULTS

Overall, 93 studies evaluating 70 different markers were included. Most studies were done on protein markers, but DNA markers and RNA markers were also investigated. Performance characteristics varied widely between different markers, but also between different studies using the same marker. Promising results were reported for some novel assays, e.g., assays based on SELDI-TOF MS or MALDI-TOF MS, for some proteins (e.g., soluble CD26 and bone sialoprotein) and also for some genetic assays (e.g., L6 mRNA), but evidence thus far is restricted to single studies with limited sample size and without further external validation.

CONCLUSIONS

Larger prospective studies using study populations representing a screening population are needed to verify promising results. In addition, future studies should pay increased attention to the potential of detecting precursor lesions.

Epithelial molecular markers in the peripheral blood of patients with colorectal cancer

Despite the modest improvements in patient survival from colorectal cancer in the last few decades, the overall five-year survival rate remains at 40 to 45 percent. Surgical resection is the mainstay of treatment for colorectal cancer; however, nearly one-half of all patients who undergo a potentially curative resection will relapse because of undetected micrometastasis. The fact that the overall survival rate remains poor strongly suggests that the dissemination of these cells occurs early in the disease process and emphasizes the need for finding feasible diagnostic methods with sufficient sensitivity and specificity. The most commonly used technique for the detection of nucleic acid material of disseminated tumor cells is the polymerase chain reaction. We critically review the literature on DNA and messenger ribonucleic acid molecular markers that have been used for the detection of circulating tumor cells in the peripheral blood of patients with colorectal cancer and other solid tumors as appropriate for comparison. The cytokeratins, particularly cytokeratin 19 and cytokeratin 20, are the most investigated prognostic markers, but even for these questions remain about their clinical value, and hence most recent studies are utilizing a combination of factors. There is an urgent need for standardized isolation and analysis techniques to be adopted thus allowing large-scale, appropriately controlled, multicenter trials to be undertaken on the most promising candidate markers.

Multiple molecular markers as predictors of colorectal cancer in patients with normal perioperative serum carcinoembryonic antigen levels

PURPOSE

In this study, a high-sensitivity colorimetric membrane array method was used to detect circulating tumor cells (CTC) in the peripheral blood of colorectal cancer (CRC) patients with normal perioperative serum carcinoembryonic antigen (CEA) levels. This membrane array method was evaluated as a potential diagnostic and postoperative surveillance tool.

STUDY DESIGN

Membrane arrays consisting of a panel of mRNA markers that include human telomerase reverse transcriptase, cytokeratin-19, cytokeratin-20, and CEA mRNA were used to detect CTCs in the peripheral blood of 157 postoperative CRC patients with normal perioperative serum CEA levels and in 80 healthy individuals. Digoxigenin-labeled cDNA were amplified by reverse transcription-PCR from the peripheral blood samples, which were then hybridized to the membrane array. The sensitivity, specificity, and accuracy of membrane arrays for the detection of CTCs were then calculated.

RESULTS

Using the four markers in combination, expression of any three markers or all the four markers in this panel was significantly correlated with the clinicopathologic characteristics, including depth of tumor invasion, lymph node metastasis, tumor-node-metastasis stage, and postoperative relapse (all P < 0.05). The interval between the detection of all four positive molecular markers and subsequent elevated CEA ranged from 3 to 8 months (median 6 months). The expression of all four mRNA markers was an independent predictor for postoperative relapse. CRC patients with all four mRNA markers expression showed a significantly poorer survival rate than those with less than four positive markers.

CONCLUSIONS

The constructed membrane array method was helpful in the early prediction of postoperative relapse in CRC patients with normal perioperative serum CEA levels.

Molecular biomarkers for cancer detection in blood and bodily fluids

Cancer is a major and increasing public health problem worldwide. Traditionally, the diagnosis and staging of cancer, as well as the evaluation of response to therapy have been primarily based on morphology, with relatively few cancer biomarkers currently in use. Conventional biomarker studies have been focused on single genes or discrete pathways, but this approach has had limited success because of the complex and heterogeneous nature of many cancers. The completion of the human genome project and the development of new technologies have greatly facilitated the identification of biomarkers for assessment of cancer risk, early detection of primary cancers, monitoring cancer treatment, and detection of recurrence. This article reviews the various approaches used for development of such markers and describes markers of potential clinical interest in major types of cancer. Finally, we discuss the reasons why so few cancer biomarkers are currently available for clinical use.

Circulating nucleic acids in plasma and serum: recent developments

Nucleic acids (DNA and RNA) have been detected in plasma, serum, urine, and other body fluids from healthy subjects as well as in patients. The ability to detect and quantitate specific DNA and RNA sequences has opened up the possibility of diagnosis and monitoring of diseases. With the recent developments in the field of circulating nucleic acids the application in the diagnostic field has increased. The recent discovery of epigenetic changes in placental/fetal DNA and the detection of fetal/placental-specific RNAs have made it possible to use this technology in all pregnancies irrespective of the gender of the fetus. With the application of mass spectrometry and other techniques to this field, it is now possible to detect very small amounts of specific DNA in the presence of excess of other nonspecific nucleic acids (e.g., detection of mutations in fetal DNA in the presence of excess of maternal DNA). Circulating nucleic acids have now been shown to be useful in other conditions, such as diabetes mellitus, trauma, stroke, and myocardial infarction. In oncology, detection and monitoring of tumors is now possible by the detection of tumor-derived nucleic acids. In spite of these advances questions regarding the origin and biologic significance of circulating nucleic acids remain to be answered. Furthermore pre-analytical and analytical aspects of this field remain to be standardized.

Biology of circulating mRNA: still more questions than answers?

A few years after the first description of free-circulating DNA in plasma and serum, the detection of tumor-associated overexpressed mRNA in plasma was also reported. This observation has been confirmed and it seems to be clear that the presence of free-circulating RNA is a ubiquitous phenomenon. In this short review I will discuss some basic aspects of the release mechanisms for the RNA, its biological meaning, and clinical value.

Molecular detection of circulating tumor cells in the peripheral blood of patients with colorectal cancer using RT-PCR: significance of the prediction of postoperative metastasis

BACKGROUND

Approximately 20%-45% of colorectal cancer (CRC) patients ultimately develop local recurrence or metastasis following curative surgical resection. The latter is caused by tumor cells shed from the primary carcinoma prior to or during operation, currently undetected by standard clinical staging. Fortunately, the presence of tumor cells in peripheral blood can be detected by molecular methods and is being regarded increasingly as a clinically relevant prognostic factor.

MATERIALS AND METHODS

To detect the presence of circulating tumor cells and evaluate their relationship to postoperative metastatic relapse, we simultaneously examined human telomerase reverse transcriptase (hTERT), cytokeratin-19 (CK-19), cytokeratin-20 (CK-20), and carcinoembryonic antigen (CEA) mRNA (messenger RNA) in the peripheral blood of 72 CRC patients and 30 healthy individuals. Using a reverse-transcriptase polymerase chain reaction (RT-PCR), these tumor-related mRNAs were amplified; in addition, analyses were carried out for their correlation with patients' clinicopathologic features, as well as the occurrence of postoperative metastasis.

RESULTS

In RT-PCR analysis of the peripheral blood, 69.4% (50 out of 72), 66.7% (48 out of 72), 52.8% (38 out of 72), and 72.2% (52 out of 72) of CRC patients were positive for hTERT, CK-19, CK-20, and CEA mRNA respectively. All 30 healthy individuals were negative for hTERT and CEA mRNA expression, while 2 were positive for either CK-19 mRNA or CK-20 mRNA expression. The detection of CEA mRNA was significantly correlated with depth of tumor invasion (P=0.012), vessel invasion (P=0.035), TNM stage (P<0.0001), and postoperative metastasis (P<0.0001), while positive hTERT mRNA was correlated with TNM stage (P=0.037) and CK-19 was correlated with depth of tumor invasion (P=0.039) and postoperative metastasis (P=0.017). In addition, multivariate logistic regression showed that only CEA mRNA was an independent and significant predictor of postoperative metastasis (P=0.006). Our findings suggest that CEA mRNA may be a more reliable marker than hTERT, CK-19, and CK-20 for the detection of circulating cancer cells in the peripheral blood of CRC patients.

CONCLUSIONS

Using RT-PCR for the detection of CEA mRNA is feasible and may be a promising tool for early detection of micrometastatic circulating tumor cells in CRC patients. CRC patients expressing positive CEA mRNA in peripheral blood have a significantly higher risk of postoperative metastasis. Nevertheless, confirmation of CEA mRNA as a prognostic predictive factor requires the continuation of patient follow-up.

Circulating nucleic acids (CNAs) and cancer--a survey

It has been known for decades that it is possible to detect small amounts of extracellular nucleic acids in plasma and serum of healthy and diseased human beings. The unequivocal proof that part of these circulating nucleic acids (CNAs) is of tumor origin, initiated a surge of studies which confirmed and extended the original observations. In the past few years many experiments showed that tumor-associated alterations can be detected at the DNA and RNA level. At the DNA level the detection of point mutations, microsatellite alterations, chromosomal alterations, i.e. inversion and deletion, and hypermethylation of promoter sequences were demonstrated. At the RNA level the overexpression of tumor-associated genes was shown. These observations laid the foundation for the development of assays for an early detection of cancer as well as for other clinical means.

Real-Time Quantification of Human Telomerase Reverse Transcriptase mRNA in the Plasma of Patients with Prostate Cancer

The aim of this study was to evaluate the potential diagnostic value of quantitative analysis of human telomerase reverse transcriptase (hTERT) mRNA in plasma for noninvasive diagnosis of prostate cancer (PCa). Expression levels of hTERT were analyzed by real-time quantitative RT-PCR in 68 patients showing elevated prostate-specific antigen (PSA) levels and a control group of 44 healthy volunteers. Sensitivity and specificity were determined and compared to the corresponding PSA values. Median values for hTERT gene expression in the PCa patients (0.72 ng; range 0.01-12.86) were statistically significantly higher (P < 0.001) than in the control group (0.13 ng; 0.02-0.35). Patients with clinically confirmed prostatitis showed lower plasma hTERT expression than PCa patients (0.29; 0.01-66.07). At a cutoff value of 0.35 sensitivity and specificity for the diagnosis of PCa were 81% and 60%, respectively. We suggest that hTERT mRNA in plasma is a very specific and sensitive method that may aid to differentiate between malignant and nonmalignant prostate tissue and may be a useful marker (in combination with PSA) for early PCa diagnosis.

Real-time reverse transcription PCR and the detection of occult disease in colorectal cancer

Molecular diagnostics offers the promise of accurately matching patient with treatment, and a resultant significant effect on improved disease outcome. More specifically, the real-time reverse transcription polymerase chain reaction (qRT-PCR), with its combination of conceptual simplicity and technical utility, has the potential to become a valuable analytical tool for the detection of mRNA targets from tissue biopsies and body fluids. Its potential is particularly promising in cancer patients, both as a prognostic assay and for monitoring response to therapy. Colorectal cancer provides an instructive paradigm for this potential as well as the problems associated with its use as a clinical assay. Currently, histopathological staging, which provides a static description of the anatomical extent of tumour spread within a surgical specimen, defines patient prognosis. The detection of lymph node (LN) metastasis constitutes the most important prognostic factor in colorectal cancer and as the primary indicator of systemic disease spread, LN status determines the choice of postoperative adjuvant chemotherapy. However, its limitations are emphasised by the considerable prognostic heterogeneity of patients within a given tumour stage: not all patients with LN-negative cancers are cured and not all patients with LN-positive tumours die from their disease. This has resulted in a search for more accurate staging protocols and has seen the introduction of the concept of "molecular staging", the incorporation of molecular parameters into clinical tumour staging. Quantification of disease-associated mRNA is one such parameter that utilises the qRT-PCR assay's potential for generating quantitative results. These are not only more informative than qualitative data, but contribute to assay standardisation and quality management. This review provides an assessment of the practical value to the clinician of RT-PCR-based molecular diagnostics. It points out reasons for the many contradictory results encountered in the literature and concludes that there is an urgent need for standardisation at every level, starting with pre-assay sample acquisition and template preparation, assay protocols and post-assay analysis.

Gene expression analysis and clinical diagnosis

BACKGROUND

A new basis for diagnostic tests is being provided by the vast amount of data on gene expression that are now becoming available through large-scale measurement of mRNA abundance. The insights gained from these resources are most likely going to provide both a better basic understanding of disease mechanisms, and to identify molecular markers for more precise diagnoses and for prediction of prognosis and treatment response.

METHODS

Some quantitative RT-PCR assays are utilized today for diagnosis of both malignant and non-malignant disease, but the use of gene expression measurements in clinical medicine can be expected to increase dramatically.

CONCLUSIONS

There are important technical issues that must be adequately solved in order to obtain robust assays, such as standardized protocols with appropriate quality controls that ensure reliable data for the specific samples being analysed and good inter-laboratory reproducibility.

Detecting cell-free circulating hTERT mRNA in the plasma may identify a subset of nonsmall cell lung cancer patients

Human telomerase reverse transcriptase (hTERT), the catalytic subunity of telomerase, a marker of cell immortalization, is upregulated in most tumors, including nonsmall cell lung cancer (NSCLC). However, little is known about the role of assessing cell-free plasma circulating hTERT mRNA for tracing these tumors. We investigated by RT-polymerase chain reaction (PCR) and real-time quantitative PCR the prevalence and functional implications of hTERT mRNA in both tumor tissue and paired plasma samples in 34 (27 males and 7 females) stages I-IIIB NSCLC patients (21 adenocarcinomas and 13 squamous-cell carcinomas) by using intron- and exon-spanning primers. Plasma samples of ten healthy volunteers and normal lung tissue were used as negative controls. We detected hTERT mRNA in the plasma of 4 out of 34 (12%) tumor patients, but none was detected in the ten plasma samples of healthy volunteers. Normal lung tissue was completely devoid of hTERT mRNA. No association was found between hTERT plasma mRNA and clinicopathologic variables of the patients' population. We conclude that cell-free circulating hTERT mRNA is detectable in a subset of patients, whereas it is consistently absent in healthy volunteers. It can be added to the panel of multiple genetic tracers to detect lung cancer in the plasma of patients, although, per se, it is not specific for this tumor.