Prognostic significance of circulating tumour cells following surgical resection of colorectal cancers: a systematic review

Prognostic and clinicopathological significance of circulating tumor cells detected by RT-PCR in non-metastatic colorectal cancer: a meta-analysis and systematic review

Background

Circulating tumor cells (CTCs) have been accepted as a prognostic marker in patients with metastatic colorectal cancer (mCRC, UICC stage IV). However, the prognostic value of CTCs in patients with non-metastatic colorectal cancer (non-mCRC, UICC stage I-III) still remains in dispute. A meta-analysis was performed to investigate the prognostic significance of CTCs detected by the RT-PCR method in patients diagnosed with non-mCRC patients.

Methods

A comprehensive literature search for relevant articles was performed in the EmBase, PubMed, Ovid, Web of Science, Cochrane library and Google Scholar databases. The studies were selected according to predetermined inclusion/exclusion criteria. Using the random-effects model of Stata software, version12.0 (2011) (Stata Corp, College Station, TX, USA), to conduct the meta-analysis, and the hazard ratio (HR), risk ratio (RR) and their 95% confidence intervals (95% CIs) were regarded as the effect measures. Subgroup analyses and meta-regression were also conducted to clarify the heterogeneity.

Results

Twelve eligible studies, containing 2363 patients with non-mCRC, were suitable for final analyses. The results showed that the overall survival (OS) (HR = 3.07, 95% CI: [2.05–4.624], P < 0.001; I² = 55.7%, P = 0.008) and disease-free survival (DFS) (HR = 2.58, 95% CI: [2.00–3.32], P < 0.001; I² = 34.0%, P = 0.085) were poorer in patients with CTC-positive, regardless of the sampling time, adjuvant therapy and TNM stage. CTC-positive was also significantly associated with regional lymph nodes (RLNs) metastasis (RR = 1.62, 95% CI: [1.17–2.23], P = 0.003; I² = 74.6%, P<0.001), depth of infiltration (RR = 1.41, 95% CI: [1.03–1.92], P = 0.03; I² = 38.3%, P = 0.136), vascular invasion (RR = 1.66, 95% CI: [1.17–2.36], P = 0.004; I² = 46.0%, P = 0.135), tumor grade (RR = 1.19, 95% CI: [1.02–1.40], P = 0.029; I² = 0%, P = 0.821) and tumor-node-metastasis (TNM) stage(I, II versus III) (RR = 0.76, 95% CI 0.71–0.81, P < 0.001; I² = 0%, P = 0.717). However, there was no significant relationship between CTC-positive and tumor size (RR = 1.08, 95% CI: [0.94–1.24], P = 0.30; I² = 0%, P = 0.528).

Conclusions

Detection of CTCs by RT-PCR method has prognostic value for non-mCRC patients, and CTC-positive was associated with poor prognosis and poor clinicopathological prognostic factors. However, the prognostic value of CTCs supports the use of CTCs as an indicator of metastatic disease prior to the current classification of mCRC meaning it is detectable by CT/MRI.

Does the type of anesthesia really affect the recurrence-free survival after breast cancer surgery?

Background

Although previous studies have suggested that propofol inhibits cancer recurrence and metastasis, the association between anesthetic agents and the recurrence of breast cancer has not been clearly investigated. We compared total intravenous anesthesia and balanced anesthesia with volatile agents to investigate the differences in their effects on recurrence-free survival and overall survival after breast cancer surgery.

Materials and Methods

The electronic medical records of 2,729 patients who underwent breast cancer surgery between November 2005 and December 2010 were retrospectively reviewed to analyze the factors associated with recurrence-free survival after surgery. Cox proportional hazards models were used to identify the risk factors for cancer recurrence and overall mortality after breast cancer surgery.

Results

Data from 2,645 patients were finally analyzed. The recurrence-free survival rate in this study was 91.2%. Tumor-node-metastasis staging exhibited the strongest association with breast cancer recurrence. However, we were unable to identify significant differences between the preventive effects of total intravenous anesthesia and those of volatile agents on postoperative breast cancer recurrence using Cox regression analyses and propensity score matching. Furthermore, the survival probability with regard to postoperative recurrence and mortality showed no significant differences among anesthetic agents.

Conclusions

Our findings suggest that the effects of total intravenous anesthesia are comparable with those of volatile agents with regard to postoperative recurrence-free survival and overall survival in patients with breast cancer.

Survival Impact of Primary Tumor Lymph Node Status and Circulating Tumor Cells in Patients with Colorectal Liver Metastases

OBJECTIVE

The aim of this study was to analyse the survival impact of primary tumor nodal status (N0/N+) in patients with resectable colorectal liver metastases (CLM), and to determine the value of circulating and disseminated tumor cells (CTCs/DTCs) in this setting.

METHODS

In this prospective study of patients undergoing resection of CLM from 2008 to 2011, peripheral blood was analyzed for CTCs using the CellSearch System^®, and bone marrow was sampled for DTC analyses just prior to hepatic resection. The presence of one or more tumor cells was scored as CTC/DTC-positive. Following resection of the primary tumor, the lymph nodes (LNs) were examined by routine histopathological examination.

RESULTS

A total of 140 patients were included in this study; 38 patients (27.1%) were negative at the primary colorectal LN examination (N0). CTCs were detected in 12.1% of all patients; 5.3% of patients in the N0 group and 14.7% of patients in the LN-positive (N+) group (p = 0.156), with the LN-positive group (N+) consisting of both N1 and N2 patients. There was a significant difference in recurrence-free survival (RFS) when analysing the N0 group versus the N+ group (p = 0.007) and CTC-positive versus CTC-negative patients (p = 0.029). In multivariate analysis, CTC positivity was also significantly associated with impaired overall survival (OS) [p = 0.05], whereas DTC positivity was not associated with survival.

CONCLUSION

In this cohort of resectable CLM patients, 27% had primary N0 colorectal cancer. Assessment of CTC in addition to nodal status may contribute to improved classification of patients into high- and low-risk groups, which has the potential to guide and improve treatment strategies.

Role of specific DNA mutations in the peripheral blood of colorectal cancer patients for the assessment of tumor stage and residual disease following tumor resection

In the present study, the detection of tumor-specific KRAS proto-oncogene, GTPase (KRAS) and B-Raf proto-oncogene, serine/threonine kinase (BRAF) mutations in the peripheral blood of colorectal cancer (CRC) patients at all stages and adenomas was used for the estimation of disease stage prior to surgery and for residual disease following surgery. A total of 65 CRC patients were enrolled. The primary tumor tested positive for the specific mutations (KRAS mutations in codons 12, 13, 61, 117 or 146 and BRAF mutations in codon 600) in 35 patients. In all these patients, the specimen of normal bowel resected with the tumor was also tested for the presence of the same mutations in order to exclude the germ-line mutations. Only patients who tested positive for the specific mutation in the primary tumor were included in further analysis for the presence of tumor-specific mutation in the peripheral blood. No statistically significant differences were found between the detection rates of tumor mutations in the blood and different tumor stages (P=0.491). However, statistically significant differences in the proportions of patients with detected tumor-specific DNA mutations in the peripheral blood were found when comparing the groups of patients with R0 and R2 resections (P=0.038). Tumor-specific DNA mutations in the peripheral blood were more frequently detected in the patients with an incomplete surgical clearance of the tumor due to macroscopic residual disease (R2 resections). Therefore, the study concludes that the follow-up of somatic KRAS- and BRAF-mutated DNA in the peripheral blood of CRC patients may be useful in assessing the surgical clearance of the disease.

Does the mobilization of circulating tumour cells during cancer therapy cause metastasis?

Despite progressive improvements in the management of patients with locoregionally confined, advanced-stage solid tumours, distant metastasis remains a very common - and usually fatal - mode of failure after attempted curative treatment. Surgery and radiotherapy are the primary curative modalities for these patients, often combined with each other and/or with chemotherapy. Distant metastasis occurring after treatment can arise from previously undetected micrometastases or, alternatively, from persistent locoregional disease. Another possibility is that treatment itself might sometimes cause or promote metastasis. Surgical interventions in patients with cancer, including biopsies, are commonly associated with increased concentrations of circulating tumour cells (CTCs). High CTC numbers are associated with an unfavourable prognosis in many cancers. Radiotherapy and systemic antitumour therapies might also mobilize CTCs. We review the preclinical and clinical data concerning cancer treatments, CTC mobilization and other factors that might promote metastasis. Contemporary treatment regimens represent the best available curative options for patients who might otherwise die from locally confined, advanced-stage cancers; however, if such treatments can promote metastasis, this process must be understood and addressed therapeutically to improve patient survival.

The Role of CTCs as Tumor Biomarkers

Detection of Circulating Tumor Cells (CTCs) in peripheral blood can serve as a "liquid biopsy" approach and as a source of valuable tumor markers. CTCs are rare, and thus their detection, enumeration and molecular characterization are very challenging. CTCs have the unique characteristic to be non-invasively isolated from blood and used to follow patients over time, since these cells can provide significant information for better understanding tumour biology and tumour cell dissemination. CTCs molecular characterization offers the unique potential to understand better the biology of metastasis and resistance to established therapies and their analysis presents nowadays a promising field for both advanced and early stage patients. In this chapter we focus on the latest findings concerning the clinical relevance of CTC detection and enumeration, and discuss their potential as tumor biomarkers in various types of solid cancers. We also highlight the importance of performing comparison studies between these different methodologies and external quality control systems for establishing CTCs as tumor biomarkers in the routine clinical setting.

Long-term Survival for Patients Undergoing Volatile versus IV Anesthesia for Cancer Surgery

Background

Surgical resection remains the best option for long-term survival in many solid tumors. Surgery can, however, lead to tumor cell release into the circulation. Data have suggested differential effects of anesthetic agents on cancer cell growth. This retrospective analysis investigated the association of anesthetic technique with long-term survival in patients presenting for elective surgery in a comprehensive cancer center over 3 yr.

Methods

All patients undergoing elective surgery between June 2010 and May 2013 were included. Patients were grouped according to whether they had received volatile inhalational (INHA) or total IV anesthesia (TIVA). After excluding those who received both forms of anesthesia during the study period, Kaplan–Meier survival curves were constructed from the date of surgery to death. After propensity matching, univariate and multivariable regression models were used to compare hazard ratios for death.

Results

A total of 11,395 anesthetics using INHA or TIVA were delivered in the study period. After exclusions, 3,316 patients (796 deaths, 24%) remained in the INHA group and 3,714 (504 deaths, 13.5%) in the TIVA group. After propensity matching, 2,607 patients remained in each group (597 deaths, 22.8%, in INHA group vs. 407, 15.6%, in TIVA group). Volatile inhalational anesthesia was associated with a hazard ratio of 1.59 (1.30 to 1.95) for death on univariate analysis and 1.46 (1.29 to 1.66) after multivariable analysis of known confounders in the matched group.

Conclusions

This retrospective analysis demonstrates an association between type of anesthetic delivered and survival. This analysis alongside biological plausibility should lead to urgent prospective work exploring the effect of anesthetic technique on survival.

Effects of anaesthesia on proliferation, invasion and apoptosis of LoVo colon cancer cells in vitro

Tumour cell proliferation, invasion and apoptosis are crucial steps in tumour metastasis. We evaluated the effect of serum from patients undergoing colon cancer surgery receiving thoracic epidural and propofol anaesthesia on colon cancer cell biology. Patients were randomly assigned to receive propofol anaesthesia with a concomitant thoracic epidural (PEA, n = 20) or sevoflurane anaesthesia with opioid analgesia (SGA, n = 20). Venous blood was obtained before induction of anaesthesia and 24 hours postoperatively. The LoVo colon cancer cells were cultured with patient serum from both groups and the effects on proliferation, invasion and apoptosis were measured. Twenty-four hours after surgery, the absorbance value of LoVo cells at 10% serum concentration from PEA was decreased when compared with SGA (0.302 (0.026) vs 0.391 (0.066), p = 0.005). The inhibitory rate of LoVo cells at 10% serum concentration from PEA was higher than that from SGA (p = 0.004) 24 h after surgery. The number of invasive LoVo cells at 10% serum concentration from PEA was reduced when compared with SGA (44 (4) vs 62 (4), p < 0.001). Exposure of LoVo cells to postoperative serum from patients receiving PEA led to a higher luminescence ratio (apoptosis) than those receiving SGA (0.36 (0.04) vs 0.27 (0.05), p < 0.001). Serum from patients receiving PEA for colon cancer surgery inhibited proliferation and invasion of LoVo cells and induced apoptosis in vitro more than that from patients receiving SGA. Anaesthetic technique might influence the serum milieu in a way that affects cancer cell biology and, thereby, tumour metastastasis.

Circulating and disseminated tumour cells in head and neck cancer

BACKGROUND

Multimodal treatment options in head and neck squamous cell carcinoma have allowed for greater control of locoregional disease, but this has not translated into a significant overall survival advantage for patients. This is partially because these treatment modalities have no influence over the rate of development of distant metastases.

OBJECTIVE

This article summarises the current methods of detecting circulating and disseminated tumour cells. It also discusses how these cells can offer prognostic value in head and neck squamous cell carcinoma, and considers questions posed by the identification of these cells.

METHODS

A literature search of relevant journal articles was performed using ScienceDirect and PubMed databases, and a general article search was conducted using the online search engine Google.

RESULTS AND CONCLUSION

The evidence presented in this article indicates that circulating tumour cells and disseminated tumour cells may be clinically useful as prognostic markers or in the assessment of response to treatment in head and neck squamous cell carcinoma.

Treatment Rationale and Study Design for Clinical Trial on the Efficacy of UFT/LV for Stage II Colorectal Cancer With Risk Factors for Recurrence (JFMC46-1201)

BACKGROUND

The usefulness of adjuvant chemotherapy for stage II colon cancer has not been established. Meanwhile, the presence of stage II colon cancer with high-risk factors for recurrence has been reported. To our knowledge, no prospective study of adjuvant chemotherapy for stage II colon cancer with high-risk factors has been implemented to date.

PATIENTS AND METHODS

This study is a prospective nonrandomized controlled study based on patients' selection of treatment option, including randomized therapeutic decision-making, to evaluate the usefulness of adjuvant chemotherapy with tegafur-uracil (UFT) with leucovorin (LV) for stage II colon cancer with high-risk factors for recurrence, compared with surgery alone. Five courses of UFT/LV therapy will be given as follows: UFT (300 mg/m(2)/d) with LV (75 mg/d) will be orally administered in 3 doses per day. Treatment will be received daily for 28 days, followed by a 7-day rest or will be received daily for 5 days, followed by a 2-day rest. For both regimens, 1 course will last 5 weeks, and 5 courses will be given. The primary end point is disease-free survival. A propensity score matching will be conducted based on 7 variables that represent risk factors to minimize selection bias in a comparison between the nonrandomized arms. For this nonrandomized comparison, a target sample size is set at 1200 (400 and 800 patients for the surgery alone and UFT/LV groups, respectively) and 1720 patients will be enrolled. In this study we aim to evaluate the therapeutic usefulness of adjuvant chemotherapy with UFT/LV for stage II colorectal cancer with risk factors for recurrence.

Hydroxyethyl starch 200/0.5 decreases circulating tumor cells of colorectal cancer patients and reduces metastatic potential of colon cancer cell line through inhibiting platelets activation

Platelets play an important role in metastasis of circulating tumor cells (CTCs). It has been demonstrated that hydroxyethyl starch (HES) inhibits platelets function. However, the effect of HES on CTCs in patients with colorectal cancer remains unclear. We compared the effects of HES 200/0.5 and HES 130/0.4 on CTCs and platelets activation of colorectal patients in this study. Additionally, the effects of HES 200/0.5 or HES 130/0.4 on metastasis ability of colon cancer cell line that stimulated by activated platelets have been explored. In vivo, 90 patients undergoing colorectal cancer radical surgery received randomly 15 mL/kg of HES 200/0.5 (n = 45) or HES 130/0.4 (n = 45) infusion before surgery. Platelet glycoprotein IIb/IIIa (GPIIb/IIIa), CD62P and platelets aggregation rate (PAR) were evaluated pre-, intra- and postoperatively. Cytokeratin-20 (CK-20) mRNA was detected by reverse transcriptase polymerase chain reaction before and after surgery. In vitro, colon cancer SW480 cells were incubated with activated platelets in the presence or absence HES 200/0.5 or HES 130/0.4. The metastasis ability of SW480 cells was assessed by Transwell assay. The results showed that CK-20 mRNA positive rate in HES 200/0.5 group after surgery was decreased significantly as compared to group HES 130/0.4 (χ (2) = 6.164, P = 0.013). Simultaneously, a more pronounced inhibition of platelets activation was observed in group HES 200/0.5. A positive correlation between platelets activation marker and CK-20 mRNA positive rate was found. In vitro, HES 200/0.5, but not HES 130/0.4, decreased the invasion and migration ability of SW480 cells that induced by activated platelets. Besides, the expression of GPIIb/IIIa, CD62P and PAR was inhibited more strongly in group HES 200/0.5 than those in group HES 130/0.4. In summary, we found that HES 200/0.5 significantly decreased CTCs of patients undergoing colorectal cancer radical surgery as compared to HES 130/0.4, which might be associated with inhibiting platelets activation of HES 200/0.5. Furthermore, HES 200/0.5, but not HES 130/0.4, reduced the metastatic potential of colon cell line stimulated by activated platelets through depressing platelets activation. Modulation of platelets activity may be a novel strategy to minimize the risk of metastasis during surgery.

Impact of circulating tumor cells in colorectal cancer patients undergoing laparoscopic surgery

Laparoscopic surgery has recently been widely used for various benign colorectal diseases as well as colorectal cancer. Although laparoscopic surgery has been shown to be with similar prognostic results for certain groups of colorectal cancer patients. The influence of laparoscopic procedures on the oncologist results, especially free tumor cell spreading is still a concern for some surgeons. Tumor cells found in the peripheral blood of patients with cancer are termed circulating tumor cells (CTCs). Presence of CTCs in the peripheral blood of patients with colorectal cancer has been reported to be associated with disease stage, poor prognosis, tumor progression, response to therapy, and drug resistance. Whether laparoscopic procedure enhances tumor spreading during operation remains unknown. Significantly less CTC detected during laparoscopic surgery than open surgery for colorectal cancer has been reported. In our previous experience, no significant elevation in CTC level was found in most patients during laparoscopic resection of colorectal cancer. We have shown that laparoscopic surgery had no significantly deleterious effect on CTCs in colorectal cancer patients. In this review, we aim at the impact of CTCs in patients with colorectal cancer undergoing laparoscopic surgery. The prognostic significance of CTCs in patients with colorectal cancer will also be addressed.

Platinum-based chemotherapy: gastrointestinal immunomodulation and enteric nervous system toxicity

The efficacy of chemotherapeutic treatment of colorectal cancer is challenged by severe gastrointestinal side effects, which include nausea, vomiting, constipation, and diarrhea. These symptoms can persist long after the treatment has been ceased. An emerging concept is the ability of platinum-based drugs to stimulate immunity, which is in contrast to conventional chemotherapeutic agents that are immunosuppressive. Here, we review the immunomodulatory aspects of platinum-based anticancer chemotherapeutics and their impact on gastrointestinal innervation. Given the bidirectional communication between the enteric nervous system and gastrointestinal immune system; exploring the consequences of platinum-induced immunogenicity will facilitate better understanding of gut dysfunction caused by chemotherapeutic agents. We propose that the development of future successful chemotherapeutics should rely on targeting the mechanisms underlying long-term gastrointestinal side effects.

May CTC technologies promote better cancer management?

In the case of cancer, death is usually not due to the primary tumor itself but due to dissemination. Analysis of the circulating tumor cells (CTCs), i.e., cells responsible for a formation of metastases, should provide information useful for the management of cancer patients, fulfilling the objectives of predictive, preventive, and personalized medicine (PPPM). Despite promising results, the decisions on stage of disease and how to guide the adjuvant treatment still do not include results of CTC assessment. We want to describe two major reasons why the recent diagnostic value of CTC analysis is not sufficient for clinical use. The first reason arises from the biological nature of the tumor itself and the second reason is associated with an interdisciplinary status of CTC diagnostics in the sense that it is neither a theme purely for pathologists nor for haemato-oncologists nor clinical biochemists. We anticipate that there are at least three areas where CTCs can be useful for clinical practice. The first is monitoring of treatment efficacy of cancer patients. The second is a molecular characterization of captured CTCs for targeted treatment, and the third is a cultivation of captured CTCs for drug sensitivity testing. All of these approaches allow researchers recognize and respond to changes of phenotype of cancer cells during disease progression and introduce PPPM into clinical practice.

Methods for detecting circulating cancer stem cells (CCSCs) as a novel approach for diagnosis of colon cancer relapse/metastasis

Cancer stem cells (CSCs) are believed to be resistant to currently available therapies and may be responsible for relapse of cancer in patients. Measuring circulating tumor cells (CTCs) in the blood of patients has emerged as a non-invasive diagnostic procedure for screening patients who may be at high risk for developing metastatic cancers or relapse of the cancer disease. However, accurate detection of CTCs has remained a problem, as epithelial-cell markers used to date are not always reliable for detecting CTCs, especially during epithelial-mesenchymal transition. As CSCs are required to initiate metastatic tumors, our goal was to optimize and standardize a method for identifying circulating CSCs (CCSCs) in patients, using established CSC markers. Here, we report for the first time the detection of CCSCs in the blood of athymic nude mice, bearing metastatic tumors, and in the blood of patients positive for colonic adenocarcinomas. Using a simple and non-expensive method, we isolated a relatively pure population of CSCs (CD45-/CK19+), free of red blood cells and largely free of contaminating CD45+ white blood cells. Enriched CCSCs from patients with colon adenocarcinomas had a malignant phenotype and co-expressed CSC markers (DCLK1/LGR5) with CD44/Annexin A2. CSCs were not found in the blood of non-cancer patients, free of colonic growths. Enriched CCSCs from colon cancer patients grew primary spheroids, suggesting the presence of tumor-initiating cells in the blood of these patients. In conclusion, we have developed a novel diagnostic assay for detecting CSCs in circulation, which may more accurately predict the risk of relapse or metastatic disease in patients. As CSCs can potentially initiate metastatic growths, patients positive for CCSCs can be treated with inhibitory agents that selectively target CSCs, besides conventional treatments, to reduce the risk of relapse/metastatic disease for improving clinical outcomes.

Core needle biopsy of breast cancer tumors increases distant metastases in a mouse model

INTRODUCTION: Incisional biopsies, including the diagnostic core needle biopsy (CNB), routinely performed before surgical excision of breast cancer tumors are hypothesized to increase the risk of metastatic disease. In this study, we experimentally determined whether CNB of breast cancer tumors results in increased distant metastases and examine important resultant changes in the primary tumor and tumor microenvironment associated with this outcome. METHOD: To evaluate the effect of CNB on metastasis development, we implanted murine mammary 4T1 tumor cells in BALB/c mice and performed CNB on palpable tumors in half the mice. Subsequently, emulating the human scenario, all mice underwent complete tumor excision and were allowed to recover, with attendant metastasis development. Tumor growth, lung metastasis, circulating tumor cell (CTC) levels, variation in gene expression, composition of the tumor microenvironment, and changes in immunologic markers were compared in biopsied and non-biopsied mice. RESULTS: Mice with biopsied tumors developed significantly more lung metastases compared to non-biopsied mice. Tumors from biopsied mice contained a higher frequency of myeloid-derived suppressor cells (MDSCs) accompanied by reduced CD4 + T cells, CD8 + T cells, and macrophages, suggesting biopsy-mediated development of an increasingly immunosuppressive tumor microenvironment. We also observed a CNB-dependent up-regulation in the expression of SOX4, Ezh2, and other key epithelial-mesenchymal transition (EMT) genes, as well as increased CTC levels among the biopsy group. CONCLUSION: CNB creates an immunosuppressive tumor microenvironment, increases EMT, and facilitates release of CTCs, all of which likely contribute to the observed increase in development of distant metastases.

The potential benefits of the use of regional anesthesia in cancer patients

Cancer is a leading cause of morbidity and mortality worldwide. In light of demographic changes among other factors, it is anticipated this trend will continue. Surgical resection is the primary method of treating solid tumours. Unfortunately, even with the use of adjunct therapies, metastatic disease is a leading cause of death in people with cancer. Recent evidence suggests choice of anesthetic technique may influence cancer outcome. This review considers the latest evidence regarding local and regional anesthesia in the context of cancer biology. There is a focus on the indirect and direct mechanisms involved. An integrated approach is used such that diverse areas of research are explored; ranging from epigenetics to cell death pathways. With a better understanding of how regional anesthesia and/or local anesthetics interact with cancer cells, these techniques can be trialed and evaluated to ascertain potential clinical benefits in cancer patients. Thus far, there is insufficient evidence to warrant a change in clinical practice.

Single-cell sequencing technologies: current and future

Intensively developed in the last few years, single-cell sequencing technologies now present numerous advantages over traditional sequencing methods for solving the problems of biological heterogeneity and low quantities of available biological materials. The application of single-cell sequencing technologies has profoundly changed our understanding of a series of biological phenomena, including gene transcription, embryo development, and carcinogenesis. However, before single-cell sequencing technologies can be used extensively, researchers face the serious challenge of overcoming inherent issues of high amplification bias, low accuracy and reproducibility. Here, we simply summarize the techniques used for single-cell isolation, and review the current technologies used in single-cell genomic, transcriptomic, and epigenomic sequencing. We discuss the merits, defects, and scope of application of single-cell sequencing technologies and then speculate on the direction of future developments.

Molecular biomarkers for the detection of metastatic colorectal cancer cells

Approximately half of all patients with colorectal cancer develop local recurrence or distant metastasis during the course of their illness. Recently, the molecular detection of metastatic cancer cells in various types of clinical samples, such as lymph nodes, bone marrow, peripheral blood, and peritoneal lavage fluid, has been investigated as a potential prognostic marker. The prognostic value of molecular tumor cell detection was independent of the type of detection method used. As assays become more sensitive and quantitative, a more thorough assessment of the cancer status of patients will be based on molecular markers alone. At present, it is difficult to conclude that one specific molecular marker is superior to others. Comparative analyses are recommended to assess the prognostic impact of molecular analyses in the same patient and determine the biomarkers that provide the most accurate prognostic information.

Are we causing the recurrence-impact of perioperative period on long-term cancer prognosis: Review of current evidence and practice

Newer developments in the field of chemotherapeutic drug regimes, radiotherapy, and surgical techniques have improved the prognosis of cancer patients tremendously. Today increasing numbers of patients with aggressive disease are posted for surgical resection. The advances in reconstructive flap surgery offer the patient a near normal dignified postresection life. Hence, the expectations from the patients are also on the rise. Anesthetic challenges known in oncosurgery are that of difficult airway, maintenance of hemodynamics and temperature during long surgical hours, pain management, and postoperative intensive care management. But, recently acquired data raised the possibility of the anesthetic technique and conduct of perioperative period as a possible contributory factor in the growth and possible recurrence of the primary tumor. The foundation of the concept is somewhat fragile and not supported by conclusive evidence. In fact, like any other controversial topic in medicine, contradictory reports of the favorable effects of anesthetic technique and medications are plenty in the literature. This is the basis of our article where we have analyzed the current evidence available in the literature and how these and the forthcoming large scale studies may revolutionize the practice of oncoanesthesia.

Postoperative serum methylation levels of TAC1 and SEPT9 are independent predictors of recurrence and survival of patients with colorectal cancer

BACKGROUND

Serum carcinoembryonic antigen (CEA) is the only marker recommended for surveillance of colorectal cancer (CRC) recurrence; its sensitivity and specificity, however, are suboptimal. This study sought to evaluate the values of postoperative serum methylation levels of 7 genes for prognostication and especially for recurrence detection after curative resection.

METHODS

This prospective cohort study included 150 patients with stage I-III CRC from whom 3 consecutive blood sampling was taken 1 week before, and 6 months and 1 year after operation. Methylation levels of 7 genes were evaluated via quantitative methylation-specific polymerase chain reaction. Serum CEA was measured in parallel. Univariate and multivariate survival analyses were followed by construction of receiver operating characteristic curves for recurrence detection.

RESULTS

After a median follow-up of 59 months, 43 patients (28.7%) developed recurrent lesions. High serum methylation levels of TAC1 in serum at 6-month follow-up (6M-FU), and SEPT9 at 1-year follow-up (1Y-FU) were independent predictors for tumor recurrence and unfavorable cancer-specific survival (CSS) (P < .05 in all tests). Serum NELL1 methylation levels were significant alone for CSS at both 6M-FU and 1Y-FU, but not for disease-free survival. Dynamic changes of TAC1 and SEPT9 with methylation increment were also independently predictive for recurrence (P < .05 in all tests). More importantly, TAC1 at 6M-FU and SEPT9 at 1Y-FU exhibited earlier detection of potential recurrences compared with concurrent serum CEA.

CONCLUSIONS

Levels of TAC1 and SEPT9 methylation detected in postoperative sera of patients with CRC appear to be novel promising prognostic markers and may probably be considered for monitoring of CRC recurrence.

Evaluation of prognostic significance of circulating tumor cells detection in rectal cancer patients treated with preoperative radiotherapy: prospectively collected material data

The aim of this study was to evaluate the prognostic value of circulating tumor cells (CTC) in nonmetastatic rectal cancer patients treated with short-term preoperative radiotherapy. In this single-center trial, 162 patients with rectal cancer after preoperative short-term radiotherapy (5 × 5 Gy) were recruited from January, 2008 to September, 2011. Clearance of CTC was determined in 91 patients enrolled in the molecular analysis. CTC presence was evaluated with real-time reverse transcription polymerase chain reaction assay (qPCR) based on the expression of three tumor genetic markers: carcinoembryonic antigen (CEA), cytokeratin 20 (CK20), and/or cancer stem cells marker CD133 (CEA/CK20/CD133). We found that CTC detection 7 days after surgery was of prognostic significance for the local recurrence (P value = 0.006). CTC detected preoperatively and 24 hours after resection had no prognostic value in cancer recurrence; however, there was a significant relationship between CTC prevalence 24 hours after surgery and lymph node metastasis (pN1-2). We also confirmed a significant clearance of CTC in peripheral blood (PB) 24 hours after surgery. Preoperative sampling is not significant for prognosis in rectal cancer patients treated with short-term radiotherapy. Detection of CTC in PB 7 days after surgery is an independent factor predicting local recurrence in this group of patients.

Micrometastatic cancer cells in lymph nodes, bone marrow, and blood: Clinical significance and biologic implications

Cancer metastasis may be regarded as a progressive process from its inception in the primary tumor microenvironment to distant sites by way of the lymphovascular system. Although this type of tumor dissemination often occurs in an orderly fashion via the sentinel lymph node (SLN), acting as a possible gateway to the regional lymph nodes, bone marrow, and peripheral blood and ultimately to distant metastatic sites, this is not a general rule as tumor cells may enter the blood and spread to distant sites, bypassing the SLN. Methods of detecting micrometastatic cancer cells in the SLN, bone marrow, and peripheral blood of patients have been established. Patients with cancer cells in their SLN, bone marrow, or peripheral blood have worse clinical outcomes than patients with no evidence of spread to these compartments. The presence of these cells also has important biologic implications for disease progression and the clinician's understanding of the process of cancer metastasis. Further characterization of these micrometastatic cancer cells at each stage and site of metastasis is needed to design novel selective therapies for a more "personalized" treatment.

Regional anaesthesia and cancer metastases: the implication of local anaesthetics

Clinical and basic science studies have demonstrated the anti-inflammatory properties of local anaesthetics. Recent studies have begun to unravel molecular pathways linking inflammation and cancer. Regional anaesthesia is associated in some retrospective clinical studies with reduced risk of metastasis and increased long-term survival. The potential beneficial effects of regional anaesthesia have been attributed mainly to the inhibition of the neuroendocrine stress response to surgery and to the reduction in the requirements of volatile anaesthetics and opioids. Because cancer is linked to inflammation and local anaesthetics have anti-inflammatory effects, these agents may participate in reducing the risk of metastasis, but their mechanism of action is unknown. We demonstrated in vitro that amide local anaesthetics attenuate tumour cell migration as well as signalling pathways enhancing tumour growth and metastasis. This has provided the first evidence of a molecular mechanism by which regional anaesthesia might inhibit or reduce cancer metastases.

Does regional anaesthesia and analgesia or opioid analgesia influence recurrence after primary cancer surgery? An update of available evidence

Cancer continues to be a key cause of morbidity and mortality worldwide and its overall incidence continues to increase. Anaesthetists are increasingly faced with the challenge of managing cancer patients, for surgical resection to debulk or excise the primary tumour, or for surgical emergencies in patients on chemotherapy or for the analgesic management of disease- or treatment-related chronic pain. Metastatic recurrence is a concern. Surgery and a number of perioperative factors are suspected to accelerate tumour growth and potentially increase the risk of metastatic recurrence. Retrospective analyses have suggested an association between anaesthetic technique and cancer outcomes, and anaesthetists have sought to ameliorate the consequences of surgical trauma and minimise the impact of anaesthetic interventions. Just how anaesthesia and analgesia impact cancer recurrence and consequent survival is very topical, as understanding the potential mechanisms and interactions has an impact on the anaesthetist's ability to contribute to the successful outcome of oncological interventions. The outcome of ongoing, prospective, randomized trials are awaited with interest.

Prognostic significance of isolated tumor cells in patients with colorectal cancer in recent 10-year studies

Circulating tumor cells (CTCs) that detach from the primary tumor and move into the circulation are detected in patients with metastatic cancer. The discovery of such cancer cells has been used as a predictor of recurrence and prognosis, although a consensus regarding such applications has not been reached. Peritoneal cytology may be used for identifying high risk of recurrence or mortality, whereas the intraoperative presence of tumor cells in drainage veins, bone marrow, or the liver is not always useful for evaluating the prognosis. The reported positive rate for tumor cells in the peripheral blood of patients with colorectal cancer, including metastasis, has varied from 10 to 80%; however, numerous studies have demonstrated significant differences in the recurrence and mortality rates between patients with and without isolated tumor cells (ITCs) in the peripheral blood. However, the clinical significance of CTCs as an absolute prognostic factor has not been elucidated, since the measurement methodologies and/or the number of cases differed between the studies. Future prospective studies including larger patient populations may elucidate the utility of routine detection of ITCs in daily practice.

Investigation of free cancer cells in peripheral blood using CEA mRNA expression in perioperative colorectal cancer patients

The aim of this study was to evaluate the impact of laparoscopic surgery (Lap) on circulating free tumor cells in colorectal cancer patients. In this study, we selected carcinoembryonic antigen (CEA) mRNA expression in peripheral blood as the marker of the circulating tumor cells and compared this marker between Lap and open colectomy (OC), to investigate differences due to surgical approach. A total of 50 patients underwent curative surgery for solitary colorectal cancer at our department, between June, 2008 and February, 2011. The patients were divided into OC and Lap groups (25 patients each). Total RNA was extracted subsequent to peripheral blood collection prior to surgery, immediately following surgery and 1, 3 and 7 days after surgery. CEA mRNA was detected with reverse transcription polymerase chain reaction (RT-PCR) and the association between peripheral blood CEA mRNA-positive rate, surgical findings and clinicopathological characteristics was investigated. The peripheral blood CEA mRNA-positive rate was significantly increased immediately after surgery, compared to the preoperative rate (P=0.001), but decreased over time. No significant differences were observed at any blood-sampling time point after postoperative day 1. The positive rate was significantly increased in the OC group immediately after surgery, compared to the preoperative rate (P=0.004). However, there were no significant differences between the rates prior to and immediately after surgery in the Lap group. The patients were then divided into those who were peripheral blood CEA mRNA-positive and -negative after surgery (postoperative positive and negative groups, respectively) and the clinicopathological characteristics were compared. Significant differences were identified between the groups in lower rectal cancer patients and patients with a large intraoperative blood loss (P=0.001 and P=0.01, respectively). In conclusion, in colorectal cancer patients, there were no significant differences in the perioperative peripheral blood CEA mRNA-positive rate or its short-term changes between patients undergoing OC and Lap surgery. It was suggested that Lap is equivalent to OC with regard to free cancer cells.

Can anaesthetic and analgesic techniques affect cancer recurrence or metastasis?

Cancer is a leading cause of morbidity and mortality worldwide and the ratio of incidence is increasing. Mortality usually results from recurrence or metastases. Surgical removal of the primary tumour is the mainstay of treatment, but this is associated with inadvertent dispersal of neoplastic cells into the blood and lymphatic systems. The fate of the dispersed cells depends on the balance of perioperative factors promoting tumour survival and growth (including surgery per se, many anaesthetics per se, acute postoperative pain, and opioid analgesics) together with the perioperative immune status of the patient. Available evidence from experimental cell culture and live animal data on these factors are summarized, together with clinical evidence from retrospective studies. Taken together, current data are sufficient only to generate a hypothesis that an anaesthetic technique during primary cancer surgery could affect recurrence or metastases, but a causal link can only be proved by prospective, randomized, clinical trials. Many are ongoing, but definitive results might not emerge for a further 5 yr or longer. Meanwhile, there is no hard evidence to support altering anaesthetic technique in cancer patients, pending the outcome of the ongoing clinical trials.

The effects of anesthetics on tumor progression

More and more cancer patients receive surgery and chronic pain control. Cell-mediated immunosuppression from surgical stress renders perioperative period a vulnerable period for tumor metastasis. Retrospective studies suggest that regional anesthesia reduces the risk of tumor metastasis and recurrence. This benefit may be due to the attenuation of immunosuppression by regional anesthesia. On the other hand, accumulating evidence points to a direct role of anesthetics in tumor progression. A variety of malignancies exhibit increased activity of voltage-gated sodium channels. Blockade of these channels by local anesthetics may help inhibit tumor progression. Opioids promote angiogenesis, cancer cell proliferation and metastasis. It will be interesting to examine the therapeutic potential of peripheral opioid antagonists against malignancy. Volatile anesthetics are organ-protective against hypoxia, however; this very protective mechanism may lead to tumor growth and poor prognosis. In this review, we examine the direct effects of anesthetics in tumor progression in hope that a thorough understanding will help to select the optimal anesthetic regimens for better outcomes in cancer patients.

Circulating tumor cells as a surrogate marker for determining clinical outcome to mFOLFOX chemotherapy in patients with stage III colon cancer

BACKGROUND

This study was aimed to detect post-chemotherapeutic circulating tumour cells (CTCs) in stage III colon cancer patients and identify those who were at high risk of relapse.

METHODS

We used human telomerase reverse transcriptase, cytokeratin-19, cytokeratin-20, and carcinoembryonic antigen (CEA) as the biomarkers to detect CTCs in 90 stage III colon cancer patients undergoing curative resection followed by mFOLFOX chemotherapy.

RESULTS

Post-chemotherapeutic relapse occurred in 30 (33.3%) patients. By univariate analysis and multivariate proportional hazards regression analysis, perineural invasion (hazard ratio (HR): 2.752; 95% confidence interval (CI): 1.026-7.381), high post-chemotherapeutic serum CEA levels (HR: 2.895; 95% CI: 1.143-7.333) and persistent presence of post-chemotherapeutic CTCs (HR: 6.273; 95% CI: 2.442-16.117) were independent predictors of post-chemotherapeutic relapse. In addition, the persistent presence of post-chemotherapeutic CTCs strongly correlated with reduced disease-free survival and overall survival. Accuracy of detecting relapse in post-chemotherapeutic stage III colon cancer patients by analysing the persistent presence of post-chemotherapeutic CTCs was higher than that by post-chemotherapeutic CEA levels (odds ratio: 50.091 vs 5.211).

CONCLUSION

The persistent presence of post-chemotherapeutic CTCs is a potential powerful surrogate marker for determining clinical outcome in stage III colon cancer patients receiving adjuvant mFOLFOX chemotherapy.

Research opportunities in intraoperative radiation therapy: the next decade 2013-2023

The reality of intraoperative radiation therapy (IORT) practice is consistent with an efficient and highly precise radiation therapy technique to safely boost areas at risk for local recurrence. Long-term clinical experience has shown that IORT-containing multi-modality regimens appear to improve local disease control, if not survival in many diseases. Research with IORT is a multidisciplinary scenario that covers knowledge from radiation beam adapted development to advance molecular biology for bio-predictability of outcome. The technical parameters employed in IORT procedures are important information to be recorded for quality assurance and clinical results analysis. In addition, specific treatment planning systems for IORT procedures are available, to help in the treatment decision-making process. A systematic revision of opportunities for research and innovation in IORT is reported including radiation beam modulation, delivery, dosimetry and planning; infrastructure and treatment factors; experimental and clinical radiobiology; clinical trials, innovation and translational research development.

Circulating tumour cells and cancer stem cells: a role for proteomics in defining the interrelationships between function, phenotype and differentiation with potential clinical applications

Research on the discovery and implementation of valid cancer biomarkers is one of the most challenging fields in oncology and oncoproteomics in particular. Moreover, it is generally accepted that an evaluation of cancer biomarkers from the blood could significantly enable biomarker assessments by providing a relatively non-invasive source of representative tumour material. In this regard, circulating tumour cells (CTCs) isolated from the blood of metastatic cancer patients have significant promise. It has been demonstrated that localised and metastatic cancers may give rise to CTCs, which are detectable in the bloodstream. Despite technical difficulties, recent studies have highlighted the prognostic significance of the presence and number of CTCs in the blood. Future studies are necessary not only to detect CTCs but also to characterise them. Furthermore, another pathogenically significant type of cancer cells, known as cancer stem cells (CSCs) or more recently termed circulating tumour stem cells (CTSCs), appears to have a significant role as a subpopulation of CTCs. This review discusses the potential application of proteomic methodologies to improve the isolation and characterisation of CTCs and to distinguish between CTCs with a poor clinical significance and those with important biological and clinical implications.

Detection of circulating tumor cells in peripheral blood of colorectal cancer patients without distant organ metastases

PURPOSE

Recently, the detection of circulating tumor cells (CTCs) in peripheral blood has become an important tool for the non-invasive assessment of micrometastases and to predict clinical outcome. The objective of this study was to investigate if the presence of CTCs in peripheral blood influences the prognosis in colorectal cancer (CRC) patients without distant organ metastases.

METHODS

The GCC mRNA and CK20 mRNA levels in peripheral blood and the serum levels of CEA of 92 CRC patients without distant organ metastasis were analyzed by quantitative RT-PCR and ELISA, respectively. Its associations with overall survival (OS) and disease-free survival (DFS) rates were analyzed.

RESULTS

Univariate analyses showed that lower OS and DFS rates were significantly associated with GCC and CK20 mRNA levels, the presence of lymph node metastases, the presence of mesenteric root lymph node metastases, and the presence of tumor emboli in vessels (p < 0.05), but not with CEA levels. Multivariate analyses showed a significant association between 1) OS and GCC mRNA levels and differentiation types and 2) DFS and the presence of tumor emboli in the vessels. Kaplan-Meier curves showed that DFS was significantly associated with the presence of poorly differentiated cells, the presence of mesenteric root lymph node metastases having received prior chemotherapy, and the presence of tumor emboli in vessels.

CONCLUSION

The detection of CTCs in peripheral blood may be useful for the prediction of clinical outcome in CRC patients without distant organ metastases.

Clinical significance of and future perspectives for hepatic arterial infusion chemotherapy in patients with liver metastases from colorectal cancer

The most common site of metastases in patients with colorectal cancer is the liver. Hepatic resection is considered to be the treatment of choice for liver metastasis from colorectal cancer; however, hepatic resection can be performed in only 20 or 25% of all patients. Recurrence develops in the remnant liver or other organs after hepatic resection in over half of all patients with liver-only metastasis. Hepatic arterial infusion (HAI) chemotherapy can provide relatively high concentrations of drugs to microscopic or macroscopic metastases in the liver, with less toxicity than systemic administration. Meta-analyses have shown HAI chemotherapy to have a significantly higher response rate than systemic chemotherapy and its effect on extrahepatic metastases is negligible. HAI chemotherapy provides much better local control of liver metastases from colorectal cancer than systemic chemotherapy. However, well-controlled studies are needed to elucidate the optimal treatment strategies for neoadjuvant and postoperative adjuvant chemotherapy that optimally combine HAI chemotherapy, molecular targeted agents, and systemic chemotherapy such as FOLFOX or FOLFIRI.

Antimetastatic potential of amide-linked local anesthetics: inhibition of lung adenocarcinoma cell migration and inflammatory Src signaling independent of sodium channel blockade

BACKGROUND

Retrospective analysis of patients undergoing cancer surgery suggests the use of regional anesthesia may reduce cancer recurrence and improve survival. Amide-linked local anesthetics have antiinflammatory properties, although the mechanism of action in this regard is unclear. As inflammatory processes involving Src tyrosine protein kinase and intercellular adhesion molecule-1 are important in tumor growth and metastasis, we hypothesized that amide-linked local anesthetics may inhibit inflammatory Src-signaling involved in migration of adenocarcinoma cells.

METHODS

NCI-H838 lung cancer cells were incubated with tumor necrosis factor-α in absence/presence of ropivacaine, lidocaine, or chloroprocaine (1 nM-100 μM). Cell migration and total cell lysate Src-activation and intercellular adhesion molecule-1 phosphorylation were assessed. The role of voltage-gated sodium-channels in the mechanism of local anesthetic effects was also evaluated.

RESULTS

Ropivacaine treatment (100 μM) of H838 cells for 20 min decreased basal Src activity by 62% (P=0.003), and both ropivacaine and lidocaine coadministered with tumor necrosis factor-α statistically significantly decreased Src-activation and intercellular adhesion molecule-1 phosphorylation, whereas chloroprocaine had no such effect. Migration of these cells at 4 h was inhibited by 26% (P=0.005) in presence of 1 μM ropivacaine and 21% by 1 μM lidocaine (P=0.004). These effects of ropivacaine and lidocaine were independent of voltage-gated sodium-channel inhibition.

CONCLUSIONS

This study indicates that amide-, but not ester-linked, local anesthetics may provide beneficial antimetastatic effects. The observed inhibition of NCI-H838 cell migration by lidocaine and ropivacaine was associated with the inhibition of tumor necrosis factor-α-induced Src-activation and intercellular adhesion molecule-1 phosphorylation, providing the first evidence of a molecular mechanism that appears to be independent of their known role as sodium-channel blockers.

Circulating tumor cells in hepatocellular carcinoma: detection techniques, clinical implications, and future perspectives

Hepatocellular carcinoma (HCC) is a primary liver cancer with a huge challenge in terms of its complex etiology and its management. The fact that the most common site of early tumor recurrence in liver transplantation for HCC is the transplanted allograft strongly suggests that circulating tumor cells (CTCs) are really an active source of HCC metastasis or recurrence. In the past decade, with the tremendous progress in the technology of CTC detection, there is convincing evidence that CTCs have great potential as a marker for metastatic disease and poor prognosis in patients with a malignancy. Currently some interesting and encouraging results have been achieved in HCC CTC detection, although the knowledge about its clinical relevance in HCC is lagging behind other major tumor types. Here we will review existing and developing methodologies for CTC detection, discuss future perspectives, and describe the potential clinical impact of the identification and molecular characterization of CTC subset or circulating cancer stem cells in HCC patients. Particular attention is given to the results based on the HCC CTC study.

Influence of surgical manipulation and surgical modality on the molecular detection of circulating tumor cells from colorectal cancer

Purpose

The aim of this study was to evaluate the relationship between the detection of circulating tumor cell molecular markers from localized colorectal cancer and the time-course of a surgical manipulation or surgical modality.

Methods

From January 2010 to June 2010, samples from the peripheral blood and the inferior mesenteric vein were collected from 42 patients with cancer of the sigmoid colon or rectum. Pre-operative, intra-operative (both pre-mobilization and post-mobilization), and post-operative samples were collected. We examined carcinoembryonic antigen (CEA) mRNA and cytokeratin-20 (CK20) mRNA by real-time reverse-transcriptase polymerase chain reaction. Changes in mRNA detection rates were analyzed according to the time of blood sample collection, the surgical modality, and patient clinicopathological features.

Results

mRNA expression rates before surgical resection did not differ between blood samples from the peripheral and inferior mesenteric veins. The detection rate for CEA and CK20 mRNA showed a tendency to increase after operative mobilization of the cancer-bearing bowel segment. Furthermore, the cumulative detection rates for CEA and CK20 mRNA increased significantly over the course of surgery (pre-mobilization vs. post-mobilization). The cumulative detection rate decreased significantly after surgical resection compared with the pre-operative rates. However, no significant difference was observed in the detection rates between different surgical modalities (laparoscopy vs. open surgery).

Conclusion

The results of this study suggest that surgical manipulation has a negative influence on the dissemination of circulating tumor cells during operations on localized colorectal cancer. However, the type of surgical technique did not affect circulating tumor cells.

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.

Evaluation of the adenocarcinoma-associated gene AGR2 and the intestinal stem cell marker LGR5 as biomarkers in colorectal cancer

We aim to estimate the diagnostic performances of anterior gradient homolog-2 (AGR2) and Leucine-rich repeat-containing-G-protein-coupled receptor 5 (LGR5) in peripheral blood (PB) as mRNA biomarkers in colorectal cancer (CRC) and to explore their prognostic significance. Real-time PCR was used to analyze AGR2 and LGR5 in 54 stages I-IV CRC patients and 19 controls. Both mRNAs were significantly increased in PB from CRC patients compared to controls. The area under the receiver-operating characteristic curves were 0.722 (p = 0.006), 0.376 (p = 0.123) and 0.767 (p = 0.001) for AGR2, LGR5 and combined AGR2/LGR5, respectively. The AGR2/LGR5 assay resulted in 67.4% sensitivity and 94.7% specificity. AGR2 correlated with pT3–pT4 and high-grade tumors. LGR5 correlated with metastasis, R2 resections and high-grade. The progression-free survival (PFS) of patients with high AGR2 was reduced (p = 0.037; HR, 2.32), also in the stage I-III subgroup (p = 0.046). LGR5 indicated a poor prognosis regarding both PFS (p = 0.007; HR, 1.013) and overall survival (p = 0.045; HR, 1.01). High AGR2/LGR5 was associated with poor PFS (p = 0.014; HR, 2.8) by multivariate analysis. Our findings indicate that the assessment of AGR2 and LGR5 in PB might reflect the presence of circulating tumor cells (CTC) and stem cell like CTC in CRC. Increased AGR2 and LGR5 are associated with poor outcomes.

Biology and significance of circulating and disseminated tumour cells in colorectal cancer

PURPOSE

More than 130 years ago, circulating tumour cells (CTCs) and disseminated tumour cells (DTCs) have been linked to metastasis. Since then, a myriad of studies attempted to characterise and elucidate the clinical impact of CTCs/DTCs, amongst others in colorectal cancer (CRC). Due to a flood of heterogeneous findings regarding CTCs/DTCs in CRC, this review aims to describe the known facts about CTC/DTC biology and clinical impact.

METHODS

To identify the basic scientific literature regarding the biology and clinical impact of CTCs/DTCs in CRC, we reviewed the literature in the PubMed database. We focused on publications written in English and published until January 2012. As search terms, we used "colorectal cancer (CRC)", "colon cancer (CC)", "CTC", "DTC", "bone marrow (BM)", "lymph node (LN)", "peripheral blood (PB)", "significance" and "prognosis".

RESULTS

CTC detection and quantification under standardised conditions is feasible. Several studies in large patient settings have revealed prognostic impact of CTCs in CRC. CRC-derived DTC detection and analysis in BM exhibits a more heterogeneous picture but also shows clinical value. Furthermore, the presence of DTCs in LN has a strong prognostic impact in CRC.

CONCLUSIONS

Clinical relevance and prognostic significance of CTCs/DTCs in CRC have been clearly demonstrated in many experimental studies. The major challenge in CTC/DTC research is now to harmonise the various identification and detection approaches and consequently to conduct large prospective multi-institutional trials to verify the use of CTCs/DTCs as a valid prognostic and predictive biomarker for clinical routine.

Prognostic significance of CTCs and CSCs of tumor drainage vein blood in Dukes' stage B and C colorectal cancer patients

The clinical significance of circulating tumor cells (CTCs) including cancer stem cells (CSCs) (CTC/CSC) in the tumor drainage vein blood of patients with colorectal cancer (CRC) is unclear. In this study, we investigated the prognostic value of CTC/CSC that express carcinoembryonic antigen (CEA) cytokeratin 19 (CK19), CK20 and/or CD133 (CEA/CK/CD133) mRNA in the tumor drainage blood of CRC patients with Dukes' stage B and C. We examined tumor drainage blood from 197 patients with Dukes' stage B and C CRC. CTCs that expressed CEA, CK19, CK20 and CD133 mRNA were detected using the quantitative real-time reverse transcription-polymerase chain reaction (RT-PCR) assay. Each mRNA level was normalized with GAPDH mRNA levels. In the relationship between the expression of CEA/CK/CD133 in the tumor drainage blood and clinicopathological factors, a significant correlation was observed between CEA/CK/CD133 expression and Dukes' stage (p<0.041). In CRC patients with Dukes' stage B and C, disease-free (DFS) and overall survival (OS) of patients with CEA/CK/CD133 positive in the tumor drainage blood were significantly worse than that of marker gene negative patients. In contrast, in patients with Dukes' stage A, no significant differences were shown between these groups. By Cox progression analysis, it was shown that CEA/CK/CD133 mRNA in tumor drainage blood was an independent prognostic factor for DFS and OS in patients with Dukes' stage B and C. These results suggest that detecting CEA/CK/CD133 mRNA in tumor drainage blood by the real-time RT-PCR method would have a prognostic value in CRC patients with Dukes' stage B and C.