Plasma DNA as a molecular marker for completeness of resection and recurrent disease in patients with esophageal cancer

Towards effectiveness of cell free DNA based liquid biopsy in head and neck squamous cell carcinoma

Liquid biopsy is a minimally invasive procedure, that uses body fluids sampling to detect and characterize cancer fingerprints. It is of great potential in oncology, however there are challenges associated with the proper handling of liquid biopsy samples that need to be addressed to implement such analysis in patients' care. Therefore, in this study we performed optimization of pre-analytical conditions and detailed characterization of cfDNA fraction (concentration, length, integrity score) in surgically treated HNSCC patients (n = 152) and healthy volunteers (n = 56). We observed significantly higher cfDNA concentration in patients compared to healthy controls (p < 0.0001) and a time dependent decrease of cfDNA concentration after tumor resection. Our results also revealed a significant increase of cfDNA concentration with age in both, healthy volunteers (p = 0.04) and HNSCC patients (p = 0.000002). Moreover, considering the multitude of HNSCC locations, we showed the lack of difference in cfDNA concentration depending on the anatomical location. Furthermore, we demonstrated a trend toward higher cfDNA length (range 35-10380 and 500-10380 bp) in the group of patients with recurrence during follow-up. In conclusion, our study provide a broad characterization of cfDNA fractions in HNSCC patients and healthy controls. These findings point to several aspects necessary to consider when implementing liquid biopsy in clinical practice including: (I) time required for epithelial regeneration to avoid falsely elevated levels of cfDNA not resulting from active cancer, (II) age-related accumulation of nucleic acids accompanied by less efficient elimination of cfDNA and (III) higher cfDNA length in patients with recurrence during follow-up, reflecting predominance of tumor necrosis.

Effect of Thoracic Epidural Anesthesia on Perioperative Neutrophil Extracellular Trapping Markers in Patients Undergoing Anesthesia and Surgery for Colorectal Cancer: A Randomized, Controlled Trial

BACKGROUND

Neutrophil extracellular trapping (NETosis) is an immunologic mechanism strongly linked with increased metastatic risk in colorectal cancer. The authors hypothesized that patients who received propofol-epidural anesthesia (PEA) would exhibit decreases in the expression of serum neutrophil myeloperoxidase (MPO) and citrullinated histone H3 (H3Cit) levels compared with patients who received general anesthesia (GA).

METHODS

Colorectal cancer surgery patients were randomly assigned to the PEA (n = 30) or GA (n = 30) group. Serum MPO, H3Cit, and metalloproteinase-9 (MMP-9) levels before surgery and 24 h after surgery were measured, and visual analogue scale (VAS) scores were recorded.

RESULTS

The patients who received PEA showed decreases in MPO (28.06 ± 11.23 vs 20.54 ± 7.29 ng/ ml; P = 0.004) and H3Cit [3.22 ± 0.86 vs 2.73 ± 0.94 ng/ ml; P = 0.042) 24 h after surgery compared with the patients subjected to GA. In addition, there was no difference in MMP-9 levels (75.98 ± 26.9 vs 73.45 ± 28.4 ng/ ml; P = 0.726). The visual analogue scale scores 2 h and 24 h after operation were significantly lower in PEA group (P < 0.05). The number of postoperative analgesia pump pressings and sufentanil consumptions within 48 h after surgery were significantly lower in the PEA group (P < 0.001).

CONCLUSIONS

Propofol-epidural anesthesia reduces the expression of NETosis (MPO and H3Cit) in serum during colorectal cancer surgery.

CLINICAL TRIAL REGISTRATION

ChiCTR2200066708 ( www.chictr.org.cn ).

Tumor regionalization after surgery: Roles of the tumor microenvironment and neutrophil extracellular traps

Surgery is unanimously regarded as the primary strategy to cure solid tumors in the early stages but is not always used in advanced cases. However, tumor surgery must be carefully considered because the risk of metastasis could be increased by the surgical procedure. Tumor surgery may result in a deep wound, which induces many biological responses favoring tumor metastasis. In particular, NETosis, which is the process of forming neutrophil extracellular traps (NETs), has received attention as a risk factor for surgery-induced metastasis. To reduce cancer mortality, researchers have made efforts to prevent secondary metastasis after resection of the primary tumor. From this point of view, a better understanding of surgery-induced metastasis might provide new strategies for more effective and safer surgical approaches. In this paper, recent insights into the surgical effects on metastasis will be reviewed. Moreover, in-depth opinions about the effects of NETs on metastasis will be discussed.

Therapies that limit the formation of web-like structures formed by white cells known as neutrophils may lower the risk of cancer spread (metastasis) following surgical tumor removal. Removing solid tumors remains a key cancer treatment, but in some cases surgery itself increases the risk of metastasis. Jong-Wan Park at Seoul National University, South Korea, and co-workers reviewed current understanding of metastasis following surgery. Surgical removal destroys the architecture supporting cancer cells but this can release tumor cells into blood vessels. The stress of deep wounds also affects immune responses, most notably neutrophil extracellular traps (NETs), web-like structures formed by neutrophils to trap and kill pathogens. NETs have previously been implicated in metastasis. In a post-surgical environment enriched in neutrophils and pro-inflammatory cytokines, NET formation may help cancer cells thrive, promoting metastasis.

Clinical relevance and prognostic role of preoperative cell-free single-stranded DNA concentrations in colorectal cancer patients

PURPOSE

Circulating cell-free single-stranded DNA (ccf-ssDNA) is extracellular DNA and it is a useful biomarker for the diagnosis of tumors and predicting the prognosis of tumors. However, the clinical usefulness of ccf-ssDNA in colorectal cancer (CRC) is not well known. Thus, the purpose of this study was to investigate the clinical usefulness of ccf-ssDNA in CRC.

METHODS

The study was conducted on 44 patients who had undergone surgery for CRC, and ccf-ssDNA level was measured before surgery and statistical analysis was performed on clinical factors.

RESULTS

The association between ccf-ssDNA level and clinicopathological factors was analyzed and compared, and these factors included age, sex, body mass index, diabetes mellitus, hypertension, tumor markers (carcinoembryonic antigen and carbohydrate antigen 19-9), tumor location, size, stage (TNM), recurrence, and death. The group with a ccf-ssDNA level of ≥7.5 ng/μL had a lower age (P=0.010), and was associated with diabetes mellitus (P=0.037) and lymph node metastasis (P=0.049). Multivariate analysis of disease-free survival showed that lymph node metastasis and ccf-ssDNA level (hazard ratio, 10.011; 95% confidence interval, 2.269-44.175; P=0.002) were independent prognostic factors for recurrence. In terms of overall survival, there were no statistically significant results except for vascular invasion.

CONCLUSION

This study showed that ccf-ssDNA level in plasma in CRC patients was an independent prognostic factor that could predict recurrence non-invasively. In this regard, further evaluation with a prospective, large sample size study will be needed to obtain additional results.

Current state of prognostication, therapy and prospective innovations for Barrett's-related esophageal adenocarcinoma: a literature review

Objective

Barrett's esophagus (BE) is the only known precursor to esophageal adenocarcinoma (EAC), which has one of the lowest 5-year survival rates in oncology. The reasons for poor survival are twofold: the large majority of diagnoses are in advanced stages (~80%) and limited treatment options, with a deficit of biology-guided therapies. As a rapidly growing public health concern with poor prognosis, research into the molecular progression for BE and novel therapeutics for EAC currently has high clinical utility. Review of the literature reveals that innovative analysis of metaplastic progression from BE to EAC at a molecular level can shed light on the underlying transformative probabilities of BE into malignant pathologies and may impact current of future therapeutic modalities for management of these diseases.

Background

EAC is the fastest increasing cancer in the United States with a 600% increase over the past 25 years. This cancer arises from dysplastic tissue of BE, a complication of gastroesophageal reflux disease (GERD). Chronic acid and bile reflux in the distal esophagus initiates a metaplastic conversion of normal squamous epithelium to premalignant intestinalized columnar epithelium. Patients with BE have a 125-fold higher risk of cancer compared to the general population.

Methods

We critically reviewed the current status of BE monitoring, and subsequent therapeutic strategies being used in patients who have progressed to cancer. Also, new diagnostic tools and therapeutic candidates for BE-related EAC are discussed. Highly-targeted searches of databases containing recent original peer-reviewed papers were utilized for this review.

Conclusions

Novel and well-described biomarkers analyzed in the patient's diseased tissue will provide for more powerful diagnostics, but also possess the potential to develop strategies for personalized management and identify targets for intervention to either cease disease progression or treat BE and/or EAC. Since millions of Americans develop BE without progressing to cancer, there is a critical need to identify the small percentage of Barrett's patients who possess hallmarks of disease progression or carcinogenesis with novel screening techniques. Incorporation of such tools into standard screening protocols for BE surveillance and/or therapy would be critical to detect malignant transformations before clinically obvious cancer ever develops.

Tumor circulome in the liquid biopsies for digestive tract cancer diagnosis and prognosis

Digestive tract cancer is one of the main diseases that endanger human health. At present, the early diagnosis of digestive tract tumors mainly depends on serology, imaging, endoscopy, and so on. Although tissue specimens are the gold standard for cancer diagnosis, with the rapid development of precision medicine in cancer, the demand for dynamic monitoring of tumor molecular characteristics has increased. Liquid biopsy involves the collection of body fluids via non-invasive approaches, and analyzes biological markers such as circulating tumor cells, circulating tumor DNA, circulating cell-free DNA, microRNAs, and exosomes. In recent years, liquid biopsy has become more and more important in the diagnosis and prognosis of cancer in clinical practice due to its convenience, non-invasiveness, high specificity and it overcomes temporal-spatial heterogeneity. Therefore, this review summarizes the current evidence on liquid biopsies in digestive tract cancers in relation to diagnosis and prognosis.

Targeted sequencing of circulating cell-free DNA in stage II-III resectable oesophageal squamous cell carcinoma patients

BACKGROUND

The aim of this study was to investigate the potential of cell-free DNA (cfDNA) as a disease biomarker in oesophageal squamous cell carcinoma (ESCC) that can be used for treatment response evaluation and early detection of tumour recurrence.

METHODS

Matched tumour tissue, pre- and post-surgery plasma and WBCs obtained from 17 ESCC patients were sequenced using a panel of 483 cancer-related genes.

RESULTS

Somatic mutations were detected in 14 of 17 tumour tissues. Putative harmful mutations were observed in genes involved in well-known cancer-related pathways, including PI3K-Akt/mTOR signalling, Proteoglycans in cancer, FoxO signalling, Jak-STAT signalling, Chemokine signalling and Focal adhesion. Forty-six somatic mutations were found in pre-surgery cfDNA in 8 of 12 patients, with mutant allele frequencies (MAF) ranging from 0.24 to 4.91%. Three of the 8 patients with detectable circulating tumour DNA (ctDNA) had stage IIA disease, whereas the others had stage IIB-IIIB disease. Post-surgery cfDNA somatic mutations were detected in only 2 of 14 patients, with mutant allele frequencies of 0.28 and 0.36%. All other somatic mutations were undetectable in post-surgery cfDNA, even in samples collected within 3-4 h after surgery.

CONCLUSION

Our study shows that somatic mutations can be detected in pre-surgery cfDNA in stage IIA to IIIB patients, and at a lower frequency in post-surgery cfDNA. This indicates that cfDNA could potentially be used to monitor disease load, even in low disease-stage patients.

Detection of Coxiella burnetii Using Silicon Microring Resonator in Patient Blood Plasma

Blood plasma from patients is a powerful resource for diagnosing infectious disease due to it having many genetic materials as well as being relatively easy to obtain. Thus, various biosensors have been investigated for diagnosing diseases in blood plasma. However, there are no optimized and validated sensors for clinical use due to the low sensitivity, complexity, and difficulties of removing the inhibitors from plasma samples. In this study, we described a silicon microring resonator sensor used to detect Coxiella burnetii from the blood plasma of Q-fever patients in a label-free, real-time manner. Q-fever is an infectious disease caused by Coxiella burnetii via direct contact or inhalation aerosols. We validated this biosensor in the blood plasma of 35 clinical samples (including 16 Q fever samples infected with Coxiella burnetii and 19 samples infected with other febrile diseases. The biosensors are capable of rapid (10 min), highly sensitive (87.5%), and specific (89.5%) detection in plasma samples compared to the use of the conventional method.

Liquid biopsy in pancreatic cancer: the beginning of a new era

With dismal survival rate pancreatic cancer remains one of the most aggressive and devastating malignancy. Predominantly, due to the absence of a dependable methodology for early identification and limited therapeutic options for advanced disease. However, it takes over 17 years to develop pancreatic cancer from initiation of mutation to metastatic cancer; therefore, if diagnosed early; it may increase overall survival dramatically, thus, providing a window of opportunity for early detection. Recently, genomic expression analysis defined 4 subtypes of pancreatic cancer based on mutated genes. Hence, we need simple and standard, minimally invasive test that can monitor those altered genes or their associated pathways in time for the success of precision medicine, and liquid biopsy seems to be one answer to all these questions. Again, liquid biopsy has an ability to pair with genomic tests. Additionally, liquid biopsy based development of circulating tumor cells derived xenografts, 3D organoids system, real-time monitoring of genetic mutations by circulating tumor DNA and exosome as the targeted drug delivery vehicle holds lots of potential for the treatment and cure of pancreatic cancer. At present, diagnosis of pancreatic cancer is frantically done on the premise of CA19-9 and radiological features only, which doesn't give a picture of genetic mutations and epigenetic alteration involved. In this manner, the current diagnostic paradigm for pancreatic cancer diagnosis experiences low diagnostic accuracy. This review article discusses the current state of liquid biopsy in pancreatic cancer as diagnostic and therapeutic tools and future perspectives of research in the light of circulating tumor cells, circulating tumor DNA and exosomes.

Size-selective separation and overall-amplification of cell-free fetal DNA fragments using PCR-based enrichment

This study aimed to establish a method for the selective amplification of cell-free fetal DNA (cffDNA) in maternal plasma and preserve the integrity of DNA fragments during amplification, thereby providing a sufficient amount of cffDNA to meet the requirement of routine non-invasive prenatal testing. We amplified DNA molecules in a one-reaction system without considering their particular sequences and lengths (overall amplification) by using PCR-based enrichment. We then modified PCR conditions to verify the effect of denaturation temperature on DNA amplification on various lengths of DNA (selective overall amplification). Finally, we used an optimum temperature range to amplify cffDNA selectively. Amplification results were validated by electrophoresis and real-time quantitative PCR. Our PCR-based enrichment efficiently amplified all DNA fragments with differing lengths within a single reaction system, as well as preserving the integrity of the DNA fragments. cffDNA was significantly amplified along with the selective amplification of small fragment maternal plasma DNA in an appropriate range of denaturation temperatures. We have established a PCR-based method for the simultaneous enrichment and amplification of cffDNA in order to meet the requirements of high cffDNA quantity for routine non-invasive prenatal testing.

Circulating Cell-Free DNA Levels Could Predict Oncological Outcomes of Patients Undergoing Esophagectomy for Esophageal Squamous Cell Carcinoma

Circulating cell-free DNA (cfDNA) is a potential biomarker for cancer progression but its role is unclear in patients with esophageal squamous cell carcinoma (ESCC) after esophagectomy. We investigated relationships between plasma cfDNA levels and clinicopathological parameters in ESCC patients. Eighty-one ESCC patients who received esophagectomy were enrolled. Plasma samples from these patients and 95 normal controls were collected. DNA copy numbers were measured by real-time quantitative PCR. Subjects were divided into two groups by cfDNA level. Clinicopathological data were collected retrospectively and relationships between cfDNA levels and clinical parameters were evaluated. The cfDNA level in normal controls ranged from 0–4157 copies/mL. The cfDNA level of 96.3% ESCC patients was higher than the cutoff value (2447.26 copies/mL) with a specificity of 94.1%. The mean cfDNA concentration was 5918 copies/mL in lower and 53,311 copies/mL in higher cfDNA groups. No correlations were found between clinicopathological factors and cfDNA levels except for lymphovascular invasion. Higher cfDNA levels were associated with tumor relapse (p = 0.018). Five-year disease-free survival (DFS) and overall survival (OS) rates were 34.7% and 33.8%, respectively. Patients with higher cfDNA levels had poorer DFS (p = 0.013). Patients with higher cfDNA levels had poorer OS, but not significantly (p = 0.164). Circulating cfDNA could be a biomarker for tumor relapse of ESCC with high sensitivity and specificity. Higher cfDNA levels were associated with tumor relapse and shorter DFS after esophagectomy in ESCC patients.

Genomics, microRNA, epigenetics, and proteomics for future diagnosis, treatment and monitoring response in upper GI cancers

One major objective for our evolving understanding in the treatment of cancers will be to address how a combination of diagnosis and treatment strategies can be used to integrate patient and tumor variables with an outcome-oriented approach. Such an approach, in a multimodal therapy setting, could identify those patients (1) who should undergo a defined treatment (personalized therapy) (2) in whom modifications of the multimodal therapy due to observed responses might lead to an improvement of the response and/or prognosis (individualized therapy), (3) who might not benefit from a particular toxic treatment regimen, and (4) who could be identified early on and thereby be spared the morbidity associated with such treatments. These strategies could lead in the direction of precision medicine and there is hope of integrating translational molecular data to improve cancer classifications. In order to achieve these goals, it is necessary to understand the key issues in different aspects of biotechnology to anticipate future directions of personalized and individualized diagnosis and multimodal treatment strategies. Providing an overview of translational data in cancers proved to be a challenge as different methods and techniques used to obtain molecular data are used and studies are based on different tumor entities with different tumor biology and prognoses as well as vastly different therapeutic approaches. The pros and cons of the available methodologies and the potential response data in genomics, microRNA, epigenetics and proteomics with a focus on upper gastrointestinal cancers are considered herein to allow for an understanding of where these technologies stand with respect to cancer diagnosis, prognosis and treatment.

Targeted deep DNA methylation analysis of circulating cell-free DNA in plasma using massively parallel semiconductor sequencing

AIM

To set up a targeted methylation analysis using semiconductor sequencing and evaluate the potential for studying methylation in circulating cell-free DNA (cfDNA).

MATERIALS & METHODS

Methylation of VIM, FBLN1, LTBP2, HINT2, h19 and IGF2 was analyzed in plasma cfDNA and white blood cell DNA obtained from eight hepatocellular carcinoma patients and eight controls using Ion Torrent™ PGM sequencer.

RESULTS

h19 and IGF2 showed consistent methylation levels and methylation was detected for VIM and FBLN1, whereas LTBP2 and HINT2 did not show methylation for target regions. VIM gene promoter methylation was higher in HCC cfDNA than in cfDNA of controls or white blood cell DNA.

CONCLUSION

Semiconductor sequencing is a suitable method for analyzing methylation profiles in cfDNA. Furthermore, differences in cfDNA methylation can be detected between controls and hepatocellular carcinoma cases, even though due to the small sample set these results need further validation.

Circulating cell-free DNA in serum as a biomarker for diagnosis and prognostic prediction of colorectal cancer

Background:

To verify whether the concentrations and integrity index of circulating cell-free DNA (ccf-DNA) in serum may be clinically useful for the diagnosis and progression monitoring of colorectal cancer (CRC) patients.

Methods:

Serum samples were collected from 104 with primary CRC, 85 with operated CRC, 16 with recurrent/metastatic CRC, 63 patients with intestinal polyps and 110 normal controls. Long (247 bp) and short (115 bp) DNA fragments in serum were detected by real-time quantitative PCR by amplifying the ALU repeats (ALU-qPCR). Serum carcinoembryonic antigen (CEA) level was detected by ARCHITECT assay.

Results:

The median absolute serum ALU115 and ALU247/115 in primary CRC group was significantly higher than those in intestinal polyp and normal control groups (both P<0.0001), in recurrent/metastatic CRC was significantly higher compared with primary CRC (P=0.0021, P=0.0018) or operated CRC (P<0.0001, respectively) and during follow-up, ALU115 and ALU247/115 were increased before surgery and decreased significantly after surgery.

Conclusions:

Combined detection of ALU115, ALU247/115 and CEA could improve the diagnostic efficiency for CRC. Serum DNA concentrations and integrity index may be valuable in early complementary diagnosis and monitoring of progression and prognosis of CRC.

Clinical relevance of alterations in quantity and quality of plasma DNA in colorectal cancer patients: based on the mutation spectra detected in primary tumors

BACKGROUND

While circulating plasma DNA (cpDNA) likely originates in tumors, its utility is limited without knowledge of tumor mutations. This study assessed mutational spectra in primary tumors and clarified the utility of quantitative and qualitative cpDNA alterations in colorectal cancer (CRC) patients.

MATERIALS AND METHODS

Between 2005 and 2006, 191 surgical colorectal cancer patients at Taipei Veterans General Hospital were enrolled in a study of mutational spectra of 155 mutations in 74 genes. Concentrations of cpDNA in 133 patients were measured by Taqman qPCR. The measured endpoint was overall survival (OS) after surgery. The prognostic value was determined using the log-rank test and Cox regression analysis.

RESULTS

Of 191 tumors, 208 mutations in 17 genes were found in 137 tumors (71.7 %). Mutation frequencies were 38.7 % in KRAS, followed by APC (23.0 %), TP53 (19.9 %), PIK3CA (7.3 %), and BRAF (4.2 %). The median cpDNA in stage I, II, and III patients was 4,300, 4,800, and 5,600 copies/mL, respectively, increasing to 13,000 copies/mL in stage IV disease (p = .003). From 90 primary tumors with mutations, the sensitivity of cpDNA mutations were 24.0, 45.0, and 27.3 % in the stage I, II, and III disease, respectively, increasing to 87.5 % in stage IV. The 5-year OS of CRC patients with low cpDNA was significantly better than that of patients with high cpDNA (p = .001). Stepwise elimination showed cpDNA to be a strong prognostic factor for OS.

CONCLUSIONS

Plasma DNA alteration is a useful tool for clinical surveillance of colorectal cancer patients and might be an independent prognosticator.

The '-omics' revolution and oesophageal adenocarcinoma

Oesophageal adenocarcinoma (OAC) is the eighth most common cancer type worldwide with a dismal 5-year survival. Barrett oesophagus, the replacement of the normal squamous epithelia with glandular cells, is the first step in the pathway towards OAC. Although most patients with OAC present de novo, the presence of the easily detectable OAC precursor lesion, Barrett oesophagus, enables the possibility of early detection of high-risk patients who are more likely to progress. Currently, identification of high-risk patients depends on histopathological assessment of dysplasia with no regards to molecular pathogenesis. In the future, screening and risk stratification initiatives for Barrett oesophagus that incorporate molecular profiles might permit improved early diagnosis and intervention strategies with the possibility of preventing OAC. For the majority of patients presenting de novo at an advanced stage, combining so-called -omics datasets with current clinical staging algorithms might enable OACs to be better classified according to distinct molecular programmes, thereby leading to better targeted treatment strategies as well as cancer monitoring regimes. This Review discusses how the latest advances in -omics technologies have improved our understanding of the development and biology of OAC, and how this development might alter patient management in the future.

Role of quantitative and qualitative characteristics of free circulating DNA in the management of patients with non-small cell lung cancer

BACKGROUND

The release of DNA into peripheral blood is a common event in cancer patients, occurring as a consequence of necrotic and apoptotic processes typical of tumor cells. However, free circulating DNA (fcDNA) is also present in patients with benign diseases and in healthy individuals. Both quantitative and qualitative aspects of fcDNA have been studied as potential biomarkers in a number of tumor types. In particular, quantitative analysis of fcDNA has been shown to play an important role in the diagnosis of non-small cell lung cancer (NSCLC), because of its ability to discriminate between healthy subjects and individuals with NSCLC. Additionally, fcDNA in cancer patients derives predominantly from tumor tissue and, as such, it can be used for the molecular characterization of the primary tumor. Targeted therapies in NSCLC have, in recent years, produced promising results, highlighting the importance of molecular profiling of the primary cancer lesions. Considering that little or no tumor material is available for at least some of the patients, the possibility of using fcDNA for molecular analysis becomes increasingly important. In the present review we evaluated several quantitative and qualitative aspects of fcDNA that could be instrumental for the differential diagnosis of lung disease.

CONCLUSIONS

There is ample evidence in the literature to support the possible use of peripheral blood-derived fcDNA in the early diagnosis and molecular characterization of lung cancer. This non-invasive method may also turn out to be valuable in monitoring drug response and in identifying induced mechanisms of drug resistance. Before it can be implemented in routine clinical practice, however, additional efforts are needed to standardize the methodology.

Multi-modality therapy for cancer of the esophagus and GE junction

Cancers of the esophagus and gastroesophageal junction (GEJ) are associated with a high mortality rate. In the United States, the incidence of adenocarcinoma of the distal esophagus and GEJ is rising at an alarming rate. Decades of investigation have established the impact on survival of neoadjuvant platinum-based chemotherapy as well as chemoradiation for locally advanced tumors. Distant recurrence remains the most common pattern of failure and efforts to improve therapeutic outcome should focus on optimizing systemic therapy. Induction chemotherapy before preoperative chemoradiation and postoperative adjuvant chemotherapy are approaches to intensify systemic therapy delivery and deserve further investigation. The integration of targeted therapies and development of predictive biomarkers to identify subgroups of patients who are likely to benefit will mark the future of neoadjuvant treatment in this disease.

Detection of cancer-specific epigenomic changes in biofluids: powerful tools in biomarker discovery and application

The genetic and epigenetic material originating from tumour that can be found in body fluids of individuals with cancer harbours tumour-specific alterations and represents an attractive target for biomarker discovery. Epigenetic changes (DNA methylation, histone modifications and non-coding RNAs) are present ubiquitously in virtually all types of human malignancies and may appear in early cancer development, and thus they provide particularly attractive markers with broad applications in diagnostics. In addition, because changes in the epigenome may constitute a signature of specific exposure to certain risk factors, they have the potential to serve as highly specific biomarkers for risk assessment. While reliable detection of cancer-specific epigenetic changes has proven to be technically challenging, a substantial progress has been made in developing the methodologies that allow an efficient and sensitive detection of epigenomic changes using the material originating from body fluids. In this review we discuss the application of epigenomics as a tool for biomarker research, with the focus on the analysis of DNA methylation in biofluids.

Prognostic and predictive roles for circulating biomarkers in gastrointestinal cancer

Circulating tumor cells (CTCs) and circulating free DNA (cfDNA) have been studied as promising prognostic and predictive tumor-derived biomarkers in the bloodstream of patients with gastrointestinal malignancies because they may be an alternative noninvasive tool to tumor tissue biopsies. Quantification and molecular characterization of CTCs and cfDNA may provide additional insights into cancer biology, potentially revealing novel targets to individualize cancer care. The present article aims to review the biology and current methods to assess CTCs and cfDNA, and the efforts to establish both tumor-derived biomarkers as prognostic and predictive factors in esophageal, gastric and colorectal cancer.

Roles of thymidylate synthase and dihydropyrimidine dehydrogenase expression in blood as predictors of response to multimodal therapy in esophageal cancer

BACKGROUND

Thymidylate synthetase (TS) and dihydropyrimidine dehydrogenase (DPD) RNA expression in peripheral blood was examined as a noninvasive molecular predictor of response to neoadjuvant radiochemotherapy in patients with locally advanced cancer of the esophagus.

METHODS

Blood samples were drawn from 29 patients with esophageal cancer (10 squamous cell carcinomas and 19 adenocarciomas) before neoadjuvant radiochemotherapy. After extraction of cellular tumor RNA from blood samples, quantitative expression analysis of TS and DPD was performed with quantitative real-time reverse-transcription polymerase chain reaction.

RESULTS

Twenty of 29 (68%) of patients had a minor histopathologic response, and 9 of 29 (32%) had a major response to neadjuvant radiochemotherapy. RNA expression in the blood of patients was detectable for TS in 86%, for DPD in 97%, and in 100% for β-actin. No significant associations were detected between TS and DPD expression levels and clinical variables of the patients. A high expression level for TS was associated with a minor response to neoadjuvant treatment (P = .046), while there was no significant association between DPD and response to therapy. Combined analysis of TS and DPD expression increased the specificity for the prediction of response to 100%. No major responder to therapy had high expression levels for both genes in their peripheral blood.

CONCLUSION

Quantitation of TS and DPD in peripheral blood may be a highly specific analysis to identify a subset of patients who do not respond to neoadjuvant radiochemotherapy and may therefore prevent expensive, noneffective, and potentially harmful therapies in a substantial number of patients with esophageal cancer.

Cell-free DNA in the blood as a solid tumor biomarker--a critical appraisal of the literature

Circulating cell-free DNA (cfDNA) has been suggested as a cancer biomarker. Several studies assessed the usefulness of quantitative and qualitative tumor-specific alterations of cfDNA, such as DNA strand integrity, frequency of mutations, abnormalities of microsatellites, and methylation of genes, as diagnostic, prognostic, and monitoring markers in cancer patients. Most of the papers that could be evaluated in this review resulted in a positive conclusion. However, methodical diversity without the traceability of data and differently designed and often underpowered studies resulted in divergent results between studies. In addition, the limited diagnostic sensitivity and specificity of cfDNA alterations temper the effusive hope of novel tumor markers, raising similar issues as those for other tumor markers. To validate the actual clinical validity of various cfDNA alterations as potential cancer biomarkers in practice for individual tumor types, the main problems of the observed uncertainties must be considered in future studies. These include methodical harmonization concerning sample collection, processing, and analysis with the traceability of measurement results as well as the realization of well-designed prospective studies based on power analysis and sample size calculations.

Quantitative analysis of survivin RNA expression in blood as a non-invasive predictor of response to neoadjuvant radiochemotherapy in esophageal cancer

BACKGROUND AND OBJECTIVES

Analysis of survivin RNA expression in peripheral blood as a non-invasive molecular predictor of response to neoadjuvant radiochemotherapy in patients with locally advanced cancer of the esophagus.

MATERIAL AND METHODS

Blood samples were drawn from 29 patients with esophageal cancer prior to neoadjuvant radiochemotherapy. After extraction of cellular tumor-RNA from blood samples, quantitative expression analysis of survivin was done by quantitative real-time RT-PCR.

RESULTS

Twenty of 29 (69%) of patients showed a minor histopathological response and 9 of 29 (31%) showed a major-response to neadjuvant radiochemotherapy. RNA expression in blood of patients was detectable for survivin in 27.6%, and in 100% for beta-actin. The mean survivin expression was not significantly different between minor- and major-responders. No significant associations were detected between survivin expression levels and patients clinical variables. A high expression level for survivin was significantly associated with a minor-response to neoadjuvant treatment (P = 0.042). Relative survivin expression levels above 0.15 were not associated with major histopathological response (sensitivity: 35%; specificity: 100%).

CONCLUSION

Minor-response to the applied therapy was significantly associated with a high survivin RNA expression level in patient's blood. Survivin appears to be a specific non-invasive predictor of response to neoadjuvant therapy in esophageal cancer.

Plasma DNA is more reliable than carcinoembryonic antigen for diagnosis of recurrent esophageal cancer

BACKGROUND

Carcinoembryonic antigen (CEA) and plasma DNA are known to be elevated in patients with esophageal cancer and are higher in patients with disseminated disease. The sensitivity and specificity of these markers in the diagnosis of recurrent esophageal cancer have not been compared.

STUDY DESIGN

Plasma DNA was measured using polymerase chain reaction in 45 patients with esophageal cancer and 44 asymptomatic volunteers. The 95(th) percentile (19 ng /mL) in the volunteers was used to define normal. Thirty-nine patients had localized cancer and underwent resection, and six had disseminated disease at operation. Plasma DNA was measured preoperatively in all patients, with serum CEA measured in 31. Plasma DNA was measured sequentially during followup in 21 patients, including 7 who developed recurrence. CEA was measured in 14 of 21 patients who had sequential plasma DNA measured and in 6 of 7 patients with recurrence. CEA levels greater than 5.0 ng/mL were used as cut-off.

RESULTS

Plasma DNA was more sensitive than CEA for detecting unresectable esophageal cancer (100% versus 40%), but it had a lower specificity (22% versus 89%). The positive predictive value (19% versus 40%) and negative predictive value (100% versus 89%) were similar for plasma DNA and serum CEA, respectively. Plasma DNA was also more sensitive than CEA in detecting recurrent esophageal cancer (100% versus 33%). The specificity and positive predictive values were 100% for both tests, but the negative predictive values were higher for plasma DNA. Plasma DNA rose before there was clinical evidence of recurrence in 67% compared with only 17% for CEA.

CONCLUSIONS

Elevated plasma DNA is an extremely reliable indicator of the presence of recurrent disease, and, in the majority of patients, it rises before clinical evidence of recurrence. In contrast, a normal CEA should be interpreted cautiously, because it does not exclude recurrent disease.