Detection of carcinoembryonic antigen messenger RNA-expressing cells in portal and peripheral blood during surgery does not influence relapse in colorectal cancer

The prognostic role of circulating tumor cells in colorectal cancer

Introduction: Metastasis is the main cause of cancer-associated death in colorectal cancer (CRC). The presence of circulating tumor cells (CTC) in the blood is associated with an increased risk of recurrence and poor prognosis. The clinical significance of CTCs as a novel biomarker has been extensively studied in the last decade. It has been shown that CTC detection applies to early cancer detection. The presence of CTCs is associated with metastatic spread and poor survival and is also useful as a marker for therapy response.Areas covered: We summarize the role of CTC in CRC, their clinical significance, current methods for CTC detection and challenges as well as future perspectives of CTC research.Expert commentary: The clinical significance of CTC in CRC patients is well established. Although insightful, the available marker-based approaches hampered our understanding of the CTCs and their biology, as such approaches do not take into account the heterogeneity of these cell populations. New technologies should expand the marker-based detection to multi biomarker-based approaches together with recent technological advances in microfluidics for single cell enrichment and analysis.

The CEA-/lo colorectal cancer cell population harbors cancer stem cells and metastatic cells

Serum carcinoembryonic antigen (CEA) is the most commonly used tumor marker in a variety of cancers including colorectal cancer (CRC) for tumor diagnosis and monitoring. Recent studies have shown that colonic crypt cells expressing little or no CEA may enrich for stem cells. Numerous studies have clearly shown that there exist CRC patients with normal serum CEA levels during tumor progression or even tumor relapse, although CEA itself is considered to promote metastasis and block cell differentiation. These seemingly contradictory observations prompted us to investigate, herein, the biological properties as well as tumorigenic and metastatic capacity of CRC cells that express high (CEA⁺) versus low CEA (CEA^−/lo) levels of CEA. Our findings show that the abundance of CEA^−/lo cells correlate with poor differentiation and poor prognosis, and moreover, CEA^−/lo cells form more spheres in vitro, generate more tumors and exhibit a higher potential in developing liver and lung metastases than corresponding CEA⁺ cells. Applying RNAi-mediated approach, we found that IGF1R mediated tumorigenic and capacity of CEA^−/lo cells but did not mediate those of CEA⁺ cells. Notably, our data demonstrated that CEA molecule was capable of protecting CEA^−/lo cells from anoikis, implying that CEA⁺ cells, although themselves possessing less tumorigenic and metastatic capacity, may promote metastasis of CEA^−/lo cells via secreting CEA molecule. Our observations suggest that, besides targeting CEA molecule, CEA^−/lo cells may represent a critical source of tumor progression and metastasis, and should therefore be the target of future therapies.

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.

Meta-analysis Reveals the Prognostic Value of Circulating Tumour Cells Detected in the Peripheral Blood in Patients with Non-Metastatic Colorectal Cancer

Detecting circulating tumour cells (CTCs) is considered as effective and minimally invasive technique to predict the prognosis of patients with metastatic colorectal cancer (CRC), but its clinical validity is still conflicting in patients without metastasis. We performed this meta-analysis to evaluate whether detection of CTCs in the peripheral blood can be used as a prognostic marker for patients with non-metastatic CRC. We performed a comprehensive search of the EMBASE, PubMed, and Web of Science databases (up to September 2016). Meta-analyses were conducted using a random-effects model with the hazard ratio (HR) and 95% confidence interval (95% CI) as the effect measures. Twenty studies including 3,687 patients were eligible for inclusion. Overall analyses demonstrated that the presence of CTCs was significantly associated with aggressive disease progression (HR = 2.57, 95% CI = 1.64-4.02, P _{heterogeneity}  < 0.001, I ²  = 81.0%) and reduced disease survival (HR = 2.41, 95% CI = 1.66-3.51, P _{heterogeneity}  = 0.002, I ²  = 59.7%). Subgroup analyses further supported the prognostic effect of CTCs based on different subsets, including sampling time, detection method and cancer type. Our findings suggest that detection of CTCs in the peripheral blood has the clinical utility to indicate poor prognosis in patients with non-metastatic CRC.

Circulating cytokeratin-positive cells and tumor budding in colorectal cancer

AIM

To investigate whether circulating cytokeratin-positive (CK⁺) cells in the mesenteric blood of resected colorectal specimens are prognostic and correlate with tumor budding.

METHODS

Fifty-six colorectal specimens were collected between 9/2007 and 7/2008. Blood from the mesenteric vein was drawn immediately after receiving the fresh and unfixed specimens in the pathology department. After separation of the mononuclear cells by Ficoll-Hypaque density-gradient centrifugation, cytological smears were immunocytochemically stained for CK18. Tumor budding was evaluated on slides stained for pan-cytokeratin. The identification of ≥ 30 buds/1.3 mm² was defined as high grade budding.

RESULTS

CK⁺ cells and clusters were identified in 29 (48%) and 14 (25%) of the samples, respectively. Two cells were identified in one of three non-malignant cases. Clusters were found exclusively in malignant cases. The occurrence of CK⁺ cells or clusters was not associated with any of the evaluated clinicopathological factors, including surgical technique and tumor budding. Moreover, the occurrence of CK⁺ cells or clusters had no influence on the cancer-specific survival [75 mo (CI: 61; 88) vs 83 mo (CI: 72; 95) and 80 mo (CI: 63; 98) vs 79 mo (CI: 69; 89), respectively].

CONCLUSION

CK⁺ cells and showed neither prognostic significance nor an association with tumor budding. It is very likely that CK18-staining is not specific enough to identify the relevant cells.

Circulating CD133(+)/ESA(+) cells in colorectal cancer patients

BACKGROUND

Tumor initiating cells are a small subset of cancer cells responsible for tumor growth and recurrence. The status of tumor initiating cells was measured using the surface markers CD133 (prominin-1) and ESA (epithelial-specific antigen). The aims of this study were to investigate the significance of CD133(+)/ESA(+) cells in mesenteric venous blood (MVB) and tumor mass (TM) for overall survival (OS) and disease-free survival (DFS) in colorectal cancer (CRC) patients undergoing curative resection.

MATERIALS AND METHODS

A total of 229 CRC patients undergoing curative resection were prospectively enrolled in the study. Using CD133 and ESA as surface markers, CD133(+)/ESA(+) cells were enumerated from MVB and TM using flow cytometry.

RESULTS

We analyzed the presence of CD133(+)/ESA(+) cells in TM from 158 patients and found no correlation to patient DFS, OS, or clinical stage. In 135 patients, an analysis of CD133(+)/ESA(+) cells in MVB showed an inverse correlation with both DFS and OS (P = 0.014 and P = 0.008, respectively). It exhibited an increase-then-decrease pattern with the peak in stage II patients. A multivariate Cox analysis demonstrated that the status of CD133(+)/ESA(+) cells in MVB, but not the TM, was a significant prognostic factor for DFS and OS (P = 0.003 and P = 0.011, respectively).

CONCLUSIONS

The status of CD133(+)/ESA(+) cells in MVB, but not in TM, could be a useful indicator for predicting tumor recurrence and a prognostic marker for CRC patients.

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.

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.

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.

Meta-analysis shows that detection of circulating tumor cells indicates poor prognosis in patients with colorectal cancer

BACKGROUND & AIMS

The prognostic significance of circulating (CTCs) and disseminated tumor cells in patients with colorectal cancer (CRC) is controversial. We performed a meta-analysis of available studies to assess whether the detection of tumor cells in the blood and bone marrow (BM) of patients diagnosed with primary CRC can be used as a prognostic factor.

METHODS

We searched the Medline, Biosis, Science Citation Index, and Embase databases and reference lists of relevant articles (including review articles) for studies that assessed the prognostic relevance of tumor cell detection in the peripheral blood (PB), mesenteric/portal blood (MPB), or BM of patients with CRC. Meta-analyses were performed using a random effects model, with hazard ratio (HR) and 95% confidence intervals (95% CIs) as effect measures.

RESULTS

A total of 36 studies, including 3094 patients, were eligible for final analyses. Pooled analyses that combined all sampling sites (PB, MPB, and BM) associated the detection of tumor cells with poor recurrence-free survival (RFS) (HR = 3.24 [95% CI: 2.06-5.10], n = 26, I(2) = 77%) and overall survival (OS) (2.28 [1.55-3.38], n = 21, I(2) = 66%). Stratification by sampling site showed that detection of tumor cells in the PB compartment was a statistically significant prognostic factor (RFS: 3.06 [1.74-5.38], n = 19, I(2) = 78%; OS: 2.70 [1.74-4.20], n = 16, I(2) = 59%) but not in the MPB (RFS: 4.12 [1.01-16.83], n = 8, I(2) = 75%; OS: 4.80 [0.81-28.32], n = 5, I(2) = 82%) or in the BM (RFS: 2.17 [0.94-5.03], n = 4, I(2) = 78%; OS: 1.50 [0.52-4.32], n = 3, I(2) = 84%).

CONCLUSION

Detection of CTCs in the PB indicates poor prognosis in patients with primary CRC.

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

Background:

The role of adjuvant chemotherapy after resection of colorectal cancers (CRCs) is well understood for patients with stage-I or stage-III disease. Its efficacy for those with stage-II disease remains much less clear. Many investigators have sought to identify prognostic markers that might clarify which patients have the highest risk of recurrence and would, therefore, be most likely to benefit from chemotherapy. This systematic review examines evidence for the use of peripherally sampled, circulating tumour cells (CTCs) as such a prognostic marker.

Methods:

A comprehensive literature search was used to identify studies reporting on the significance of CTCs in the postoperative blood of CRC patients.

Results:

Fourteen studies satisfied the inclusion criteria. Six of the nine studies that took blood samples 24 h or more postoperatively found detection of postoperative CTCs to be an independent predictor of cancer recurrence.

Conclusion:

The presence of CTCs in peripheral blood at least 24 h after resection of CRCs is an independent prognostic marker of recurrence. Further studies are needed to clarify the optimal time point for blood sampling and determine the benefit of chemotherapy in CTC-positive patients with stage-II disease.

Detection of epithelial cells by RT-PCR targeting CEA, CK20, and TEM-8 in colorectal carcinoma patients using OncoQuick density gradient centrifugation system

BACKGROUND

The detection of epithelial-specific mRNA correlates well with the presence of cancer cells in the peripheral blood and provides a rational explanation for subsequent metastasis.

MATERIAL AND METHODS

Forty-two, patients with colorectal cancer and 14 controls were included in our study. Peripheral blood samples were acquired at 24 h before and 48 h after laparotomy. Tissue samples were also acquired from the primary lesion. All samples were examined for the expression profile of CEA, CK20, and TEM-8.

RESULTS

Tissue samples expressed CEA in every specimen, CK20 in 30, and TEM-8 in 41. CEA and CK20 were not identified in the control blood samples while TEM-8 was detected in 4. CEA was detected in 17, CK20 in 28 and TEM-8 in 23, of the preoperative blood samples. CEA mRNA expression in preoperative blood sample and TNM stage were found independently associated with increased tumor size. Positive CEA, CK20, and TEM-8 signals were found in 25, 25, and 23 of the postoperative blood samples respectively.

CONCLUSIONS

CK20 and CEA are significantly more frequently detected in colon cancer patients than in healthy controls and can serve as markers. Cancer cell mRNA is commonly detected in the preoperative and postoperative peripheral blood samples. Tumor size was independently associated with the preoperative detection of CEA mRNA. Although TEM-8 mRNA detection in the peripheral blood showed no specificity for cancer patients or correlation with clinical stage, identification and validation of genes and proteins implicated in metastatic process needs to be further investigated.

Expression of uPAR mRNA in peripheral blood is a favourite marker for metastasis in gastric cancer cases

Urokinase-type plasminogen activator receptor (uPAR) plays a central role in the plasminogen activation cascade and participates in extracellular matrix degradation, cell migration and invasion. We evaluated the expression level of uPAR mRNA and the presence of isolated tumour cells (ITCs) in bone marrow (BM) and peripheral blood (PB) in gastric cancer patients and clarified its clinical significance. We assessed specific uPAR mRNA expression by quantitative real-time reverse transcriptase- polymerase chain reaction (RT–PCR) in BM and PB in 846 gastric cancer patients as well as three epithelial cell markers, carcinoembryonic antigen (CEA), cytokeratin (CK)-19 and CK-7. The uPAR mRNA expression in bone marrow and peripheral blood expressed significantly higher than normal controls (P<0.0001). The uPAR mRNA in BM showed concordant expression with the depth of tumour invasion, distant metastasis, and the postoperative recurrence (P=0.015, 0.044 and 0.010, respectively); whereas in PB, we observed more intimate significant association between uPAR expression and clinicopathologic variables, such as depth of tumour invasion, the distant metastasis, the venous invasion and the clinical stage (P=0.009, 0.002, 0.039 and 0.008, respectively). In addition, the uPAR mRNA expression in PB was an independent prognostic factor for distant metastasis by multivariate analysis. We disclosed that it was possible to identify high-risk patients for distant metastasis by measuring uPAR mRNA especially in peripheral blood at the timing of operation in gastric cancer patients.

Hematogenous metastasis in gastric cancer requires isolated tumor cells and expression of vascular endothelial growth factor receptor-1

PURPOSE

Recent studies of cancer metastasis have focused on the role of premetastatic gene expression and circulating tumor cells. We did a blind prospective study in gastric cancer to assess the significance of isolated tumor cells (ITC) and to test the hypothesis that vascular endothelial growth factor receptor-1 (VEGFR-1) is expressed within the bone marrow at tumor-specific, premetastatic sites.

EXPERIMENTAL DESIGN

Both bone marrow and peripheral blood samples from 810 gastric cancer patients were collected at the Central Hospital, National Cancer Center (Tokyo, Japan). The samples were transferred to Kyushu University Hospital (Beppu, Japan) where they were analyzed by quantitative real-time reverse transcription-PCR for three epithelial cell markers, carcinoembryonic antigen, cytokeratin-19, and cytokeratin-7, as well as VEGFR-1.

RESULTS

ITCs were observed in peripheral blood and bone marrow even in early stages of gastric cancer. The frequency of ITC in bone marrow was significantly associated with the stage of disease by ANOVA (P < 0.01). Gastric cancer metastasized when ITCs were observed in the presence of VEGFR-1. In the 380 patients who were ITC negative and showed low VEGFR-1 expression, synchronous (at the time of surgery) and heterochronous (recurrent) metastases were not observed.

CONCLUSIONS

ITCs circulate even in early stages of disease. Furthermore, elevated expression of VEGFR-1 facilitates the establishment of hematogenous metastases in gastric cancer. This study indicates that the simultaneous presence of ITC and VEGFR-1 expression at premetastatic sites is clinically significant for disease progression.

Does the presence of circulating tumor cells in the venous drainage of curative colorectal cancer resections determine prognosis? A meta-analysis

BACKGROUND

Hepatic metastasis can occur following curative colorectal cancer surgery despite favorable prognostic indicators, raising the question of whether detecting circulating tumor cells in the venous drainage of colorectal cancers at resection using reverse-transcriptase polymerase chain reaction would help determine prognosis. This study compares lymph node positivity, hepatic metastasis rates, and disease-free survival in circulating tumor positive versus negative patients.

METHODS

A Medline, Embase, Ovid, and Cochrane database search was conducted on all studies between 1999 and 2006 reporting the outcomes of interest. Meta-analysis was performed in line with recommendations from the Cochrane Collaboration and the Quality of Reporting of Meta-Analyses guidelines.

RESULTS

Nine studies reporting on 646 subjects published between 1998 and 2006 matched the selection criteria and were suitable for inclusion in this meta-analysis. There was a significantly higher incidence of circulating tumor cells (50%) in lymph node positive compared with negative groups (21%) [odds ratio (OR) = 3.83, confidence interval (CI) = 2.46-5.94], and a significantly increased hepatic metastases rate (21%) in circulating tumor cells positive compared with in negative patients (8%, OR = 6.38; CI = 2.67-15.25. Disease-free survival was significantly higher in the circulating tumor cell negative versus positive groups at 1 year [hazard ratio (HR) = 0.04, CI = 0-0.46], 2 years (HR = 0.05, CI = 0.01-0.31), and 3 years (HR = 0.08, CI = 0.02-0.34) post resection.

CONCLUSION

This study highlights the potential importance of free cancer cell detection in the venous drainage of colorectal cancers as a prognostic indicator and a mode of staging colorectal cancers.

Detection of carcinoembryonic antigen messenger RNA-expressing cells in peripheral blood 7 days after curative surgery is a novel prognostic factor in colorectal cancer

BACKGROUND

The significance of detection of circulating cancer cells in blood during surgery in patients with colorectal cancer (CRC) remains controversial. Experimental study revealed that the cancer cells injected from the vein disappeared completely until 7 days. The aim of this study was to clarify that the detection of circulating cancer cells in blood taken later than 7 days after curative surgery may be a prognostic factor.

METHODS

Two hundred consecutive patients with CRC who underwent potentially curative surgery were the subjects. Peripheral blood was collected between 7 and 10 days after resection. Cancer cells were detected using reverse transcriptase-polymerase chain reaction targeting carcinoembryonic antigen (CEA) messenger RNA (mRNA). The median follow-up period was 52 months (range: 34-69 months).

RESULTS

The overall positive incidence of CEA mRNA was 22%. Detection of CEA mRNA was not significantly related to conventional clinicopathological findings. Recurrence has been confirmed in 55 patients (28%). The recurrence rate was significantly higher in patients with rectal cancer, deep penetration, lymph node metastasis, preoperative chemoradiotherapy and positive CEA mRNA. The CEA mRNA positive patients showed significantly poorer disease free survival (DFS) and overall survival (OS) than the negative patients (DFS, P = 0.007; OS, P = 0.04). Multivariate analysis revealed that the positive expression of CEA mRNA (P < 0.01) as well as the tumor location and TNM stage classification was identified as the significant risk factors for recurrence.

CONCLUSIONS

Detection of CEA mRNA expressing cells in peripheral blood 7 days after curative surgery is a novel independent factor predicting recurrence in patients with CRC.