Detection of tumor cells in the portal and peripheral blood of patients with colorectal carcinoma using competitive reverse transcriptase-polymerase chain reaction

Significance of carcinoembryonic antigen mRNA in peritoneal lavage determined by transcription-reverse transcription concerted method in patients with low rectal cancer

BACKGROUND/OBJECTIVE

Positive carcinoembryonic antigen (CEA) messenger RNA (mRNA) in peritoneal lavage is associated with poor prognosis in patients with colon cancer. However, there are no reports about rectal cancer. Therefore we aimed to evaluate the frequency of positive CEA mRNA in peritoneal lavage and the significance of CEA mRNA in patients with low rectal cancer.

METHODS

A total of 55 patients with low rectal cancer who received curative surgical resection were enrolled. CEA mRNA in peritoneal lavage was measured using the transcription-reverse transcription concerted method, a quantitative RNA amplification method. The correlation between CEA mRNA and overall and peritoneal recurrence-free survival was evaluated.

RESULTS

Among 55 patients, 6 (10.9%) had positive CEA mRNA in peritoneal lavage. Patients with positive CEA mRNA resulted in significantly higher recurrence rate than those with negative CEA mRNA (p=0.007). Similarly, the local recurrence rate was significantly higher in the positive CEA mRNA group than in the negative CEA mRNA group (p=0.0009). Lymph node metastasis and positive CEA mRNA were independent risk factors for overall and local recurrence.

CONCLUSION

Positive CEA mRNA in low rectal cancer is a factor that predisposes patients to a high risk for overall recurrence, especially for local recurrence.

Diversity of assessing circulating tumor cells (CTCs) emphasizes need for standardization: a CTC Guide to design and report trials

Hematogenous spreading of tumor cells from primary tumors is a crucial step in the cascade to metastasis, the latter being the most limiting factor for patients' survival prognosis. Therefore, circulating tumor cells (CTCs) have become a field of intensive research. However, the process of isolation and identification of CTCs lacks standardization. This article presents an overview of 71 CTC studies reported in PUBMED since 2000 and focusing on colorectal cancer. These studies are evaluated regarding standardization of CTC isolation and identification, marker proteins used, study population and blood sample quality management, clinical performance, and quality measures. Overall, standardization of CTC assessment seems insufficient. Thus, comparability of CTC studies is hampered and results should be interpreted carefully. We here propose a standardized CTC guideline (CTC Guide) to prospectively design and report studies/trials in a harmonized form. Despite the current interstudy heterogeneity, the data indicate that CTC detection is of clinical relevance and CTCs should be considered as a surrogate prognostic marker. Many studies indicate the high potential for CTCs as prognostic markers, e.g., in colorectal cancer treatment. However, standardized, large-scale multicenter validation studies are still needed to pave the way for clinical implementation of CTC detection that could ameliorate individualized medicine regimes.

Detection of carcinoembryonic antigen mRNA in peritoneal lavage by the transcription-reverse transcription concerted method indicates poor prognosis in patients with stage II and III colon cancer

BACKGROUND

Peritoneal dissemination and positive peritoneal lavage cytology are associated with poor prognosis in colorectal cancer. Carcinoembryonic antigen (CEA) messenger RNA (mRNA) is often used as a marker to detect micrometastases. We aimed to evaluate the prognostic significance of CEA mRNA in the peritoneal lavage of colon cancer patients.

METHODS

Colon cancer patients (n = 201) who underwent curative operative resection between August 2009 and February 2013 were enrolled. CEA mRNA in peritoneal lavage was measured using the transcription-reverse transcription concerted method, a quantitative RNA amplification method. The correlation between CEA mRNA and overall and peritoneal recurrence-free survival was evaluated.

RESULTS

Positive CEA mRNA in peritoneal lavage was an independent risk factor for overall recurrence-free survival in colon cancer (P < .0001). Positive CEA mRNA was a risk factor for poorer overall recurrence in stage II and III patients (P = .04 and P = .02, respectively). Moreover, among stage III patients with positive CEA mRNA, the postoperative chemotherapy group had significantly lower overall and peritoneal recurrence rates than the no postoperative chemotherapy group (P = .001).

CONCLUSION

Positive CEA mRNA in peritoneal lavage was associated with high overall recurrence rates in stage II and III colon cancer. Further study is necessary to determinate the efficacy of aggressive postoperative chemotherapy for stage II and III colon cancer patients with positive CEA mRNA.

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

BACKGROUND

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

METHODS

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

RESULTS

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

CONCLUSION

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

Capture of viable circulating tumor cells in the liver of colorectal cancer patients

BACKGROUND

The incidence and number of circulating tumor cells (CTCs) in the peripheral blood of colorectal cancer patients are lower than in other cancer types, which may point to a particular biology of colorectal cancer affecting CTC detection.

METHODS

We detected CTCs in the peripheral and mesenteric blood of colorectal cancer patients by use of 2 independent technologies on the basis of different biological properties of colon cancer cells. Seventy-five patients diagnosed with localized (M0, n = 60) and metastatic (M1, n = 15) colorectal cancer were included. Peripheral and mesenteric blood samples were collected before tumor resection. We performed CTC enumeration with an EpCAM-independent enrichment method followed by the Epispot assay that detected only viable CK19-releasing CTCs. In parallel, we used the FDA-cleared EpCAM-dependent CellSearch® as the reference method.

RESULTS

The enumeration of CK19-releasing cells by the CK19-Epispot assay revealed viable CTCs in 27 of 41 (65.9%) and 41 of 74 (55.4%) (P = 0.04) patients in mesenteric and peripheral blood, respectively, whereas CellSearch detected CTCs in 19 of 34 (55.9%) and 20 of 69 (29.0%) (P = 0.0046) patients. In mesenteric blood, medians of 4 (range 0-247) and 2.7 CTCs (range 0-286) were found with Epispot and CellSearch (P = 0.2), respectively, whereas in peripheral blood, Epispot and CellSearch detected a median of 1.2 (range 0-92) and 0 CTCs (range 0-147) (P = 0.002).

CONCLUSIONS

A considerable portion of viable CTCs detectable by the Epispot assay are trapped in the liver as the first filter organ in CRC patients.

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.

Hematogenous metastatic patterns of curatively resected colon cancer were different from those of stage IV and autopsy cases

The hematogenous metastases of colon cancer have primarily been explained by the cascade hypothesis based on the cadaveric study. However, we experienced several cases with isolated lung metastasis. The metastatic patterns of a total of 982 patients with colon cancer who underwent surgery were reviewed. The incidence of single-site metastasis in curatively resected cases was significantly higher than in Stage IV cases (P = 0.002). The frequency of liver metastasis was significantly lower in curatively resected cases than in Stage IV cases (P < 0.0001). The frequencies of liver metastasis in Stage IV cases and in autopsy cases reported previously were almost the same (84%, 85%). The frequency of metastasis after curatively resection that did not include the liver was 39%, and cases of isolated lung metastases accounted for 19%. The patterns of hematogenous metastases that are inconsistent with the cascade hypothesis are more common than previously thought in clinical cases, especially in curatively resected cases.

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.

Compartmental differences of circulating tumor cells in colorectal cancer

BACKGROUND

The prognostic role of circulating tumor cells (CTCs) has been established for colorectal cancer (CRC). We investigated the qualitative and quantitative detection of CTC in the central (CVBC) and mesenteric (MVBC) venous blood compartments to elucidate the patterns of hematogenous tumor cell dissemination in patients with CRC.

METHODS

A total of 200 patients were enrolled prospectively. Blood samples were collected from the tumor-draining vein and via a central venous line. CTCs were detected and quantified by using the CellSearch system. Factors associated with CTC detection in both compartments were analyzed by using univariate and multivariate analyses.

RESULTS

CTC analyses were performed in the CVBC and MVBC in 200 and 80 patients, respectively. CTCs were found at a higher rate (P=0.01) and at a higher count (P=0.006) in the MVBC compared with the CVBC. On multivariate analyses, stage IV disease (odds ratio, 3.83; 95% confidence interval, 1.42-10.35) and increased preoperative carbohydrate antigen 19-9 level (odds ratio, 3.57; 1.30-9.79) were associated with CTC detection in the CVBC. CTCs were detected more frequently (P=0.05) and at higher numbers (P=0.05) in the CVBC of patients with low compared with mid or high rectal tumors.

CONCLUSIONS

The qualitative and quantitative detection of CTCs is higher in the MVBC compared with the CVBC of patients with CRC.

Evaluation of laparoscopic resection of colorectal carcinoma from the viewpoint of molecular biology

AIM

Detection of the possible impact of surgical management on the occurrence of minimal residual disease (MRD) in patients with colorectal carcinoma (CRC) in bone marrow samples, portal and peripheral blood samples. Comparison of MRD prevalence in patients with laparoscopic resection of CRC and those with open colorectal resection. Assessment of the potential impact of MRD on the relapse of the disease and overall survival of patients.

MATERIAL AND METHODS

The study included 124 patients with primary CRC without proven distant metastases indicated for elective laparoscopic resection and operated on between September 21, 2006 and December 31, 2008 at the Department of Surgery, Hospital and J.G. Mendel Oncological Centre Novy Jicin. 6 samples were collected from each patient to determine MRD (system venous blood and bone marrow at the beginning of surgery, venous blood from mesenteric bloodstream, system venous blood after the resection, system venous blood and bone marrow 1 month after the surgery). Detection of MRD on the basis of CEA expression was performed by real-time RT-PCR technique. The results were compared with those obtained within the similar research using the same methodology at the 2(nd) Department of Surgery, University Hospital in Olomouc (the group included 230 patients treated with open resection of CRC).

RESULTS

In the group of patients treated with laparoscopic resection, a correlation between positive MRD in the sample of bone marrow collected before the surgery and the stage of the disease was found (p < 0.035). We also recorded the impact of surgical management on MRD occurrence in system venous blood in primary negative patients (p < 0.025). However, in the course of the short period of time we have not found a statistically significant correlation between the finding in patients with stage I-III, and the period prior to the relapse of the disease (p < 0.59). With regard to the results obtained, we can expect a potential direct correlation between a positive MRD finding in system venous blood taken prior to surgery in patients with stage I-III CRC and shorter time of survival (p < 0.075). In the group of patients treated with open resection of CRC, no statistically significant relationship between the stage of the disease and MRD occurrence was found. Incidence of circulating tumour cells (CTC) in the samples of venous blood taken prior to surgery is a prognostically important factor (p < 0.05) from the viewpoint of disease-free survival (DFS). Another prognostically important factor with regard to DFS seems to be the occurrence of disseminated tumour cells (DTC) in the bone marrow taken 1 month after the surgery.

CONCLUSIONS

The data recorded suggest a relationship between MRD finding and the disease prognosis. Collection of samples as well as evaluation of results continue as we strive to include more patients in our study and to obtain more data within 5-10 years of the follow-up. The comparison between the data obtained in the laparoscopic approach and the data obtained in open resection performed from the viewpoint of molecular biology did not show a significant difference in MRD detection in the samples collected after the surgery.

Sensitivity estimates of blood-based tests for colorectal cancer detection: impact of overrepresentation of advanced stage disease

A large number of blood-based markers have been proposed for early detection of colorectal cancer (CRC). Their sensitivity for detecting CRC has mostly been evaluated in clinical settings, and found to be higher in more advanced stages compared with earlier stages of the disease. The aim of this study is to estimate the overall sensitivity of blood-based markers expected in screening settings, where the proportion of advanced stages is typically lower than in clinical settings. A systematic literature review was performed on studies evaluating sensitivity and specificity of blood-based markers for early detection of CRC. For each study, overall sensitivity expected in screening settings was estimated by weighting stage-specific sensitivities according to the stage distribution of CRC expected in the screening setting. The latter was derived from 12,605 CRC cases diagnosed in the German screening colonoscopy program during 2003-2007. Overall, 73 studies evaluating 55 blood-based markers were identified. Adjusted sensitivity was lower than reported sensitivity in 120 (90%) evaluations of different markers. Median absolute reduction in sensitivity after adjustment was 9.0% (interquartile range: 4.0-13.0) units, whereas median relative reduction was 19.5% (interquartile range: 11.3-33.3%). Blood-based markers for CRC detection reported from clinical settings showed higher sensitivities than expected in the screening setting in most cases, mainly due to substantially higher proportions of advanced stage cancers. Adjustment of sensitivity to the stage distribution expected in the screening setting is crucial to obtain realistic and comparable estimates of sensitivities.

Serum sE-selectin levels and carcinoembryonic antigen mRNA-expressing cells in peripheral blood as prognostic factors in colorectal cancer patients

BACKGROUND

This study analyzed the possible prognostic value of presurgical serum soluble (s)E-selectin levels and/or carcinoembryonic antigen (CEA) mRNA positivity in predicting the disease-free survival of colorectal cancer (CRC) patients.

METHODS

CEA mRNA (obtained from blood-borne cells by reverse transcriptase-polymerase chain reaction [RT-PCR]), tumor necrosis factor-alpha (TNF-alpha), and sE-selectin levels were analyzed in blood samples obtained from 78 patients with primary (n = 62) or recurrent (n = 16) CRC, 40 patients with benign colorectal (CR) diseases, and 78 controls.

RESULTS

CEA mRNA positivity by RT-PCR was significantly associated with advanced stage (P < .05). Median baseline sE-selectin levels were higher in patients with CRC (43 ng/mL) compared with controls (36 ng/mL) or patients with benign CR diseases (31 ng/mL, P < .001). These were significantly associated with CEA mRNA positivity by RT-PCR (P < .05). Multivariate analysis by forward stepping showed that elevated TNF-alpha (P = .001) and CEA mRNA positivity by RT-PCR (P = .0001) were independent predictors of elevated baseline sE-selectin levels. Positive presurgical sE-selectin levels were associated with an increased recurrence rate compared with patients with low levels of this molecule (P < .001). Positivity for both CEA mRNA and sE-selectin had a negative prognostic impact, with a 5-year recurrence-free survival rate of 51% compared with 95% of patients with negative parameters (P < .05).

CONCLUSIONS

Detection of presurgical serum sE-selectin levels and CEA mRNA-positive blood-borne cells in CRC patients might provide useful prognostic information in terms of recurrence-free survival, either alone or in combination, and may help in the choice of more aggressive treatment and/or more strict follow-up procedures in high-risk patients.

Circulating tumor cells: evolving evidence and future challenges

Circulating tumor cells (CTCs) are rare malignant cells found in the peripheral blood that originate from the primary tumor or metastatic sites. New techniques have been developed to isolate and characterize these cells. CTC enumeration has been incorporated into different fields of oncology as a prognostic marker, a tool to monitor therapy response, and a method to understand basic tumor characteristics. This review covers the different techniques available for isolation of CTCs, the clinical utility of CTCs in breast, prostate, and colon cancer, and future directions in this field.

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.

Circulating tumour cells during laparoscopic and open surgery for primary colonic cancer in portal and peripheral blood

BACKGROUND

The objective of this study was to detect and quantify circulating tumour cells (CTC) in peripheral and portal blood of patients who had open or laparoscopic surgery for primary colonic cancer.

METHODS

Patients in the laparoscopic-group were operated on in a medial to lateral approach ("vessels first"), in the open-group a lateral to medial approach was applied. The enumeration of CTC was performed with the CellSearch System. Intra-operative samples were taken paired-wise (from peripheral and portal circulation) directly after entering the abdominal cavity (T1), after mobilisation of the tumour baring segment (T2), and after tumour resection (T3). Ploidy of both the CTC and tissue of the primary tumour was determined for chromosome 1, 7, 8 and 17.

RESULTS

Thirty-one patients were included; 18 patients had open surgery, 13 patients were operated on laparoscopically. The percentage of samples with CTC at T1 was 7% in peripheral blood and 54% in portal blood (p=0.002). At T2, 4% and 31% respectively (p=0.031). And at T3, 4% and 26% respectively (p=0.125). The cumulative percentage of samples with CTC was significantly higher during open surgery as compared to the laparoscopic approach. Both the CTC and tissue of the primary tumour were diploid for chromosome 1, 7, 8 and 17.

CONCLUSION

The detection rate and quantity of CTC is significantly increased intra-operatively and is significantly higher in portal blood compared to peripheral blood. Significantly less CTC were detected during laparoscopic surgery probably as result of the medial to lateral approach.

Establishment and characterization of mammalian cell lines stably expressing human L-type amino acid transporters

System L (SL), a basolateral amino acid transporter, transports large neutral amino acids (LNAAs) in a Na(+)-independent manner. Previously, we identified two isoforms of transporters: L-type amino acid transporter 1 (LAT1) and 2 (LAT2) and revealed their distinct substrate selectivity and transport properties. In this study, to establish more stable human LAT1 (hLAT1) and LAT2 (hLAT2) in vitro assay systems, we established mouse cell lines stably expressing hLAT1 (S2-LAT1) and hLAT2 (S2-LAT2). Real-time quantitative RT-PCR analysis revealed that S2-LAT1 and S2-LAT2 cells express hLAT1 and hLAT2 mRNAs at 20 - 1000-fold higher levels than those of endogenous mouse Lat1 and Lat2. S2-LAT1 and S2-LAT2 mediated [(14)C]L-leucine transport properties were measured and corresponded to results observed via Xenopus oocytes. Using these cells, the data demonstrate that hLAT1 and hLAT2 exhibit different characters in the acceptance of alpha-methyl amino acids and amino acid-related compounds with bulky side chains such as thyroid hormones and melphalan. S2-LAT1 and S2-LAT2 cells are expected to facilitate hLAT1 and hLAT2 substrate recognition research and contribute to drug development by providing an efficient assay system to screen for chemical compounds that interact with hLAT1 and hLAT2.

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.

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

BACKGROUND

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

METHOD

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

RESULTS

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

CONCLUSIONS

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

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.

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

BACKGROUND

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSIONS

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

Prognostic significance of CEA levels and detection of CEA mRNA in draining venous blood in patients with colorectal cancer

BACKGROUND AND OBJECTIVES

The aims of this study were to determine carcinoembryonic antigen (CEA) levels and incidence of tumor cells using the RT-PCR technique in draining venous blood of patients with colorectal cancer, correlate the results with various histopathologic factors and determine their significance as prognostic factors.

METHODS

From 1995 to 2000, 108 patients with adenocarcinoma of the colon or rectum, underwent curative surgery and enrolled in this prospective study.

RESULTS

The 5-year survival group had significantly lower portal CEA levels compared to the hepatic metastasis outcome group. CEA mRNA was positive in the draining venous blood from 12 (11.1%) out of 108 patients included in the study. The rate of positive tumor cell detection in portal blood was significantly higher in the hepatic metastasis outcome group than in the 5-year survival and recurrence group. The proportion of patients with portal CEA > or =5 ng/ml was greater in patients with higher stage than in patients with lower stage.

CONCLUSIONS

Positive CEA mRNA in draining venous blood predicted hepatic metastases and local recurrence with accuracy over 80% but with low sensitivity of 30% and 9%, respectively. Moreover, CEA level was a sensitive indicator in hepatic metastases as sensitivity was 95% and a specific indicator in predicting 5-year survival with specificity 84%.

Squamous cell carcinoma-antigen messenger RNA level in peripheral blood predicts recurrence after resection in patients with esophageal squamous cell carcinoma

BACKGROUND

The aim of this study was to clarify whether preoperative squamous cell carcinoma-antigen messenger RNA (SCC-Ag mRNA) level in peripheral blood can be used to predict tumor recurrence after curative resection for esophageal squamous cell carcinoma.

METHODS

A prospective analysis was conducted for 46 consecutive patients who underwent curative esophagectomy and who had no residual tumor. The SCC-Ag mRNA level in the peripheral blood of each patient was measured preoperatively by using quantitative reverse transcriptase-polymerase chain reaction. Median follow-up period was 34 months.

RESULTS

Receiver operating characteristic analysis demonstrated that the optimal cutoff level of SCC-Ag mRNA was 40. Patients were divided into the high SCC-Ag mRNA level group (n = 14) and the low SCC-Ag mRNA level group (n = 32). The cumulative probabilities of tumor recurrence were higher in the high SCC-Ag mRNA level group (probability of recurrence was 71% at 2 years) than in the low group (22% at 2 years; P = .0005). SCC-Ag mRNA level (relative risk, 3.00; 95% confidence interval, 1.05-8.54; P = .040) was the strongest independent predictor of recurrence by multivariate analysis.

CONCLUSIONS

Preoperative SCC-Ag mRNA levels in the peripheral blood are the best predictive factor for recurrence in patients with esophageal squamous cell carcinoma who undergo curative resection (R0).

Treatment of synchronous peritoneal carcinomatosis and liver metastases from colorectal cancer

AIM

To report our experience of peritoneal carcinomatosis (PC) discovered during abdominal exploration in patients with liver metastases (LM).

METHODS

Liver resection plus cytoreductive surgery were combined in 24 patients with LM and moderate PC from colorectal origin treated with a curative intent between January 1993 and November 2003.

RESULTS

The mean operative time was 357+/-112 min and median blood loss was 719 ml. One postoperative death occurred and postoperative morbidity was 58%. The mean hospital stay was 21.4+/-4.2 days. Three-year overall and disease-free survival rates were respectively 41.5% (confidence interval [CI]: 23-63) and 23.6% (CI: 11-45). Seven patients are disease-free with a mean follow-up of 27.8 months after their last surgery, 3 having a repeated hepatectomy. Three patients developed a peritoneal recurrence and 13 had recurrence in the liver. The only significant prognostic factor was a number of LMs of less than 3 (p < 0.01).

CONCLUSION

A combined treatment of LM plus PC is feasible and is beneficial in selected patients presenting three or fewer metastases.

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

BACKGROUND

No consensus has been reached on whether cancer cells detected in blood during colorectal cancer (CRC) surgery may serve as a prognostic indicator.

METHODS

One hundred patients with CRC who underwent curative surgery were the subjects. Portal and peripheral blood were collected immediately after celiotomy and examined for carcinoembryonic antigen (CEA) messenger RNA (mRNA) by using competitive semi-nested reverse transcriptase-polymerase chain reaction. The median follow-up period was 59 months (range, 49-74 months).

RESULTS

Until now, recurrence has been confirmed in 13 patients (13%). The 4-year recurrence rate was 6.7% (3 of 45) in patients with CEA mRNA-positive portal blood and 20.8% (10 of 48) in patients with CEA mRNA-negative portal blood (P = .09); it was 5.6% (2 of 36) and 19.3% (11 of 57) in patients with CEA mRNA-positive peripheral blood and CEA mRNA-negative blood, respectively (P = .12). There was no difference in disease-free survival between the CEA mRNA-positive and -negative groups. The multivariate analysis showed that the presence of tumor cells in portal or peripheral blood was a factor that reduced recurrence. The relative risks were .17 (P = .01) for the portal vein and .24 (P = .07) for the peripheral vein.

CONCLUSIONS

The detection of cancer cells in blood taken during surgery is not considered to be a poor-prognostic factor in CRC.

Hepatic and extrahepatic colorectal metastases: when resectable, their localization does not matter, but their total number has a prognostic effect

BACKGROUND

The presence of extrahepatic disease (EHD) is considered a contraindication to hepatectomy in patients with colorectal liver metastases. After resection, the prognosis is based more on the total number of resected metastases (located inside and outside the liver) than on the site of these metastases (only inside the liver or not).

METHODS

A total of 308 patients with colorectal cancer underwent hepatectomy, and 84 (27%) also underwent resection of miscellaneous EHD. The study was a prospective data registration and retrospective analysis. When considering the total number of resected metastases, each liver metastasis and each EHD location was counted as one lesion. Univariate and multivariate analyses were performed.

RESULTS

The median follow-up was 99 months. The overall 5-year survival rate was 32%. In the multivariate analysis, the total number of metastases (inside or outside the liver) had a greater prognostic value than the criterion "presence or absence of EHD." Considering the total number of resected metastases (whatever their site), 5-year survival rates were 38% (SD: 4%) in the group with one to three metastases, 29% (SD: 5%) in patients with four to six metastases, and 18% (SD: 5%) in patients with more than six metastases (P = .002). A very simple prognostic score based on sex and the total number of metastases is proposed.

CONCLUSIONS

EHD, when resectable, is no longer a contraindication to hepatectomy. More importantly, the total number of the metastases, whatever their location, has a stronger prognostic effect than the site of these metastases.

What factors influence survival in patients with unresected synchronous liver metastases after resection of colorectal cancer?

OBJECTIVE

The aim of this study was to determine whether the survival of patients with untreated synchronous liver metastases after resection of a colorectal cancer was associated with any features of the primary tumour.

METHODS

Information for 398 consecutive patients with unresected liver metastases in the period 1971-2001 was examined by multivariate survival analysis.

RESULTS

Of 19 clinical and pathological variables considered, survival was independently associated only with residual tumour in a line of resection (hazard ratio (HR) 1.95), venous invasion (HR 1.87), right colonic tumour (HR 1.68), lymph node metastasis (HR 1.54), and extra-hepatic metastasis (HR 1.16); 8.3% of patients had none of these adverse features. Their 2-year overall survival rate was 39.2%, compared with only 16.5% (P < 0.001) in those with one or more adverse features.

CONCLUSIONS

These findings may assist in selecting patients most likely to benefit from treatment of hepatic metastases and in counselling patients and their relatives.

Detection of circulating tumor cells and of tumor DNA in plasma during tumor progression in rats

The role and clinical significance of circulating tumor cells and of tumor DNA in the plasma have not yet been clarified. In the present study, we compared rates of detection of tumor-derived DNA in the buffy coat to those in plasma from tumor-bearing rats, and we attempted to correlate these rates with the progression of tumors. We injected DHD/K12-PROb cancer cells subcutaneously into BD-IX rats and divided the animals into six groups according to the time between the injection of tumor cells and euthanasia. After euthanasia, macroscopic metastases were assessed and samples of blood and lung were collected. We used mutant allele-specific amplification by PCR to detect tumor-derived DNA. We detected tumor DNA in lung samples from the first week after inoculation, in plasma from the third week and in the buffy coat from the fifth week. All animals analyzed on the 11th week had macro- or micrometastases in their lungs. Regardless of group, the rate of PCR-positive plasma samples was significantly higher than that of circulating tumor cells (P=0.005). In animals with metastases, this difference was also statistically significant (P=0.008). However, neither the detection of tumor DNA in the plasma nor the presence of circulating tumor cells was strongly correlated with the presence of metastases. Thus, cell-free tumor DNA was detected sooner and more frequently than circulating tumor cells and the dissemination of tumor DNA in the plasma seems to be much more common than detectable hematogenic tumor cells during the spread of colorectal cancer.

Impact of circulating free tumor cells in the peripheral blood of colorectal cancer patients during laparoscopic surgery

Despite widespread use of laparoscopic surgery for colorectal operations, its application for curative resection of colorectal cancer is still controversial. One of the major concerns is the impact of the laparoscopic procedure on dissemination of tumor cells. The main purpose of this study was to investigate the impact of laparoscopic surgery on circulating tumor cells in colorectal cancer patients. Quantitation of circulating free tumor cells (FTCs) was performed preoperatively, during the operation, and 14 days later by means of real-time quantitative reverse transcriptasepolymerase chain reaction (RT-PCR) targeting guanylyl cyclase C (GCC) mRNA in 42 colorectal cancer patients undergoing laparoscopic resections. Despite an increasing trend of FTC detection in patients with advancing stage, there is no significant difference in the preoperative FTC level by disease stage. No elevation in FTC level was found during the laparoscopic procedure in most patients compared with their preoperative FTC value. Patients with a persistently high FTC load [per nucleated blood cells (NBCs)] (> 10(2) FTCs/10(6) NBCs) 2 weeks postoperatively portends a poor prognosis regarding disease recurrence and tumor-related mortality when compared to those with an undetectable or low FTC load (< or = 10(2) FTCs/10(6) NBCs). We concluded that the laparoscopic procedure itself had no significantly deleterious effect on circulating FTCs and that the detection of FTCs by real-time qRT-PCR might be of clinical importance during the postoperative follow-up for colorectal cancer patients.

Results of R0 resection for colorectal liver metastases associated with extrahepatic disease

BACKGROUND

Extrahepatic malignant disease has always been considered an absolute contraindication to hepatectomy for colorectal liver metastases. This study reports the long-term outcome and prognostic factors of patients undergoing extrahepatic disease resection simultaneously with hepatectomy for liver metastases.

METHODS

From January 1987 to January 2001, 75 patients underwent a complete R0 resection of extrahepatic disease simultaneously with hepatectomy for colorectal liver metastases. They were inscribed in a registry and then prospectively followed up. They represented 25% of the 294 patients who underwent an R0 hepatectomy for colorectal liver metastases during the same period.

RESULTS

The mortality rate was 2.7%, and morbidity was 25%. After a median follow-up of 4.9 years (range, 1.7-13.4 years), the overall 3- and 5-year survival rates were 45% and 28%, respectively. By using a Cox model, there was a significant difference in survival between patients with single versus multiple sites of extrahepatic disease. Also, the presence of more than five liver metastases was a significant parameter.

CONCLUSIONS

Extrahepatic disease in colorectal cancer patients with liver metastases should no longer be considered as a contraindication to hepatectomy. However, this intended R0 resection cannot be performed in 50% of laparotomized patients, and negative prognostic factors for surgery include the presence of multiple extrahepatic disease sites or more than five liver metastases.

Detection of cancer cells in mesenteric vein and peripheral vessels by measuring telomerase activity in patients with colorectal cancer

BACKGROUND

Liver metastasis is an important factor determining prognosis in colorectal cancer. The objective of this study was to assess whether colorectal cancer cells in the drainage veins can be detected by measuring telomerase activity and its detection is correlated with liver metastasis.

METHODS

Telomeric repeat amplification protocol assay in combination with an immunomagnetic sorting was used for measuring telomerase activity of epithelial cells in blood samples collected from mesenteric (tumor-drainage) vein and peripheral vessels of 41 colorectal cancer patients. Telomerase activity was calculated as relative telomerase activity (RTA) against a control template and analyzed in terms of liver metastasis.

RESULTS

RTA of mesenteric blood samples was significantly higher in patients with liver metastasis (60.8%; n=7) than in those without metastasis (19.7%; n=34; P=.019). The RTA of peripheral blood sample was also higher in patients with liver metastasis (26.8%) than in those without metastasis (11.1%; p=.17). Moreover, 57% of cases with liver metastasis exhibited a positive telomerase activity in mesenteric blood sample, whereas it was 18% in cases without metastasis.

CONCLUSIONS

Our assay was proven to be a feasible method for detecting cancer cells in tumor-drainage veins. High telomerase activity of mesenteric blood samples reflected the existence of liver metastasis of colorectal cancer.

Carcinoembryonic antigen mRNA in the mesenteric vein is not a predictor of hepatic metastasis in patients with resectable colorectal cancer: a long-term study

PURPOSE

The clinical value of carcinoembryonic antigen messenger ribonucleic acid in the draining venous blood has been controversial because of short observation period. The authors prospectively investigated the clinical significance of detection of carcinoembryonic antigen messenger ribonucleic acid in the draining venous blood to predict hepatic metastases in patients with resectable colorectal cancer.

METHODS

Drainage venous blood from 80 patients who underwent curative resections for colorectal cancer were obtained immediately before surgery to determine the presence of cancer cells by means of reverse transcription polymerase chain reaction.

RESULTS

After an average follow-up period of 52.1 months, 7 of the 35 patients (20 percent) with positive carcinoembryonic antigen messenger ribonucleic acid had hepatic metastases, whereas 2 of the 45 patients (4.5 percent) with negative carcinoembryonic antigen messenger ribonucleic acid had hepatic metastases. The cumulative probability of hepatic metastatic recurrence rate differed significantly between two patient groups with positive or negative carcinoembryonic antigen messenger ribonucleic acid expression in the drainage vein (log-rank, 4.900; P = 0.0269). However, 28 of the 35 patients (80 percent) with positive carcinoembryonic antigen messenger ribonucleic acid did not have hepatic metastases. Additionally, Cox proportional hazards models identified the presence of lymph node metastases as the only independent predictor of hepatic metastatic recurrence.

CONCLUSIONS

This study failed to demonstrate the high predictive value of carcinoembryonic antigen messenger ribonucleic acid detection in the draining venous blood for the development of hepatic metastases. However, the authors demonstrated that the presence of cancer cells in the draining venous blood was the essential and initial step to the development of hepatic metastasis.

Extrahepatic disease does not contraindicate hepatectomy for colorectal liver metastases

BACKGROUND

Extrahepatic disease has always been considered an absolute contraindication to hepatectomy for liver metastases. The present study reports the long-term outcome and prognostic factors of patients undergoing resection of extrahepatic disease simultaneously with hepatectomy for liver metastases.

METHODS

From January 1987 to January 2001, 111 (30 per cent) of 376 patients who had hepatectomy for colorectal liver metastases underwent simultaneous resection of extrahepatic disease with curative intent.

RESULTS

Surgery was considered R0 in 77 patients (69 per cent) and palliative (R1 or R2) in 34 patients (31 per cent). The mortality rate was 4 per cent and the morbidity rate 28 per cent. After a median follow-up of 4.9 years, the overall 3- and 5-year survival rates were 38 and 20 per cent respectively. The 5-year overall survival rate of patients with R0 resection only (n = 75) was 29 per cent. The difference in survival between patients with and without extrahepatic disease discovered incidentally at operation was significant, as was the number of liver metastases.

CONCLUSION

Extrahepatic disease in patients with colorectal cancer who also have liver metastases should no longer be considered an absolute contraindication to hepatectomy. However, the presence of more than five liver metastases and the incidental intraoperative discovery of extrahepatic disease remain contraindications to hepatic resection.

Relevance of disseminated tumour cells in blood and bone marrow of patients with solid epithelial tumours in perspective

Currently-used systems to predict prognosis in patients with solid epithelial tumours after surgical resection of the tumour do not give any guarantees for the individual patient. In this respect the clinical relevance of the presence of disseminated tumour cells in blood and bone marrow has been frequently studied. Because of growing awareness that information on merely the presence of disseminated tumour cells is not sufficient for prognostic and therapeutic purposes, attention for characterization of disseminated tumour cells has increased. Numerous reviews have already been published on the detection and clinical relevance of disseminated tumour cells. Therefore, this paper will mainly focus on the biological significance of these cells and discusses the (in)efficiency of the metastatic process, the genotypic and phenotypic characteristics of disseminated tumour cells, and their structure of appearance. Despite the fact that information gained on the several individual aspects is substantial, it did not render any solid solutions for individual patient management yet. Hence, a combined approach of several aspects of disseminated tumour cells together with characteristics and behaviour of the primary tumour is needed to substantially improve our knowledge on the role of disseminated tumour cells in the complex process of tumour metastasis.

Molecular detection of gene mutations and methylation abnormalities: applications in solid tumor diagnosis

As our knowledge of the genetic and epigenetic abnormalities initiating and contributing to tumorigenesis grows, so too does the scope for earlier detection of cancer in patients. This bears an immense potential impact on the clinical management of patients with or at risk of solid tumors, since arguably the greatest problem facing clinicians is late presentation. PCR-based tests have been developed to detect mutant or hypermethylated alleles in exfoliative material and plasma/serum, enabling risk-assessment and early detection programs. Although there are certain limitations, a number of studies have already demonstrated the feasibility and reliability of molecular screening in solid tumors, including colorectal and lung cancers and such molecular approaches may soon be used routinely to detect precursor lesions and early-stage cancer.