Carcinoembryonic gene member 2 mRNA expression as a marker to detect circulating enterocytes in the blood of colorectal cancer patients

Common molecular markers between circulating tumor cells and blood exosomes in colorectal cancer: a systematic and analytical review

Nearly half of patients with colorectal cancer (CRC), the third leading cause of cancer deaths worldwide, are diagnosed in the late stages of the disease. Appropriate treatment is not applied in a timely manner and nearly 90% of the patients who experience metastasis ultimately die. Timely detection of CRC can increase the five-year survival rate of patients. Existing histopathological and molecular classifications are insufficient for prediction of metastasis, which limits approaches to treatment. Detection of reliable cancer-related biomarkers can improve early diagnosis, prognosis, and treatment response prediction and recurrence risk. Circulating tumor cells (CTCs) and exosomes in peripheral blood can be used in a liquid biopsy to assess the status of a tumor. Exosomes are abundant and available in all fluids of the body, have a high half-life and are released by most cells. Tumor-derived exosomes are released from primary tumors or CTCs with selective cargo that represents the overall tumor. The current systematic review highlights new trends and approaches in the detection of CRC biomarkers to determine tumor signatures using CTC and exosomes. When these are combined, they could be used to guide molecular pathology and can revolutionize detection tools. Relevant observational studies published until July 24, 2019 which evaluated the expression of tumor markers in CTCs and exosomes were searched in PubMed, Scopus, Embase, and ISI Web of Science databases. The extracted biomarkers were analyzed using String and EnrichR tools.

Prognostic factors in the patients with T2N0M0 colorectal cancer

BACKGROUND

The 5-year survival rate of the patients with stage I colorectal cancer is about 90%; therefore, adjuvant therapy has not been recommended after radical resection; however, about 16-26% of T2N0M0 patients will be dead at 5 years despite radical curative resection. It indicated that there is a defined group of patients who are at high risk for relapse or metastasis despite radical operation. This study aimed to find the patients with T2N0M0 colorectal cancer at high risk for relapse or metastasis.

METHODS

From January 1993 to December 2014, 812 patients with histologically confirmed stage T2N0M0 primary colorectal cancer treated by radical surgery with complete clinical follow-up data were eligible for this study. The medical records of all patients were collected and were retrospectively analyzed. Survival rates were calculated using Kaplan-Meier method, and survival cures were compared using the log-rank test. Cox proportional hazards model was used to analyze the significant factors defined in univariate test.

RESULTS

The 5-year and 10-year overall survival rates were 81.9 and 67.7%, respectively. Male gender, old age, lymphovascular permeation, perineural invasion, and poor differentiation were associated with low cancer-specific survival rates in Kaplan-Meier analysis. Multivariate analyses revealed old age, lymphovascular permeation, perineural invasion, and poor differentiation as significant independent factors predicting worse prognosis (P < 0.05).

CONCLUSIONS

Old age, lymphovascular permeation, perineural invasion, and poor differentiation are risk factors for the worse prognostic patients with T2N0M0 colorectal patients who would potential benefit from more aggressive therapy.

Colorectal Cancer Biomarkers: Where Are We Now?

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

Screening for colorectal cancer

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

Molecular tests for colorectal cancer screening

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

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.

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.

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.

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).

Long-term prognostic value of detection of circulating colorectal cancer cells using CGM2 reverse transcriptase-polymerase chain reaction assay

BACKGROUND

The criteria commonly used for prognosis of colorectal cancer remain histoprognostic and are based on primarily TNM classification. The lack of discrimination of purely histoprognostic criteria is evidenced by the development of different outcomes in similarly staged patients. The aim of this work was to study the long-term prognostic value of preoperative detection of circulating enterocytes in the blood of colorectal cancer patients using the CGM2 reverse transcriptase-polymerase chain reaction (RT-PCR) assay.

METHODS

A nested RT-PCR with specific primers for CGM2 was used preoperatively to detect circulating enterocytes in 121 patients (64 men, 57 women; mean age, 70 years) with colorectal neoplasms.

RESULTS

Circulating enterocytes were detected in 58/121 (48%) patients. The positivity rate was not correlated with American Joint Committee on Cancer (AJCC) staging (stage I, 11/28 (39%); stage II, 13/34 (38%); stage III, 15/23 (65%); stage IV, 17/32 (53%); sterilized (after radiotherapy, no residual neoplasm) 2/4 (50%); not significant [NS]), but circulating enterocytes were detected more frequently in patients with metastatic lymph nodes (60% vs 41%, P = .06). Overall 5-year survival rates (mean +/- SD) were 40 +/- 13% and 45 +/- 13% for patients without and with circulating enterocytes, respectively (P = NS). Similarly, recurrence-free survival rates were 71 +/- 4% versus 72 +/- 14% (P = NS). Using univariate analysis, AJCC stage (P < .0001) was correlated with survival. AJCC stage (P = .007) and obstructive neoplasms (P = .043) were correlated with recurrence-free survival. Using multivariate analysis, AJCC stage was correlated with survival and recurrence-free survival.

CONCLUSIONS

Preoperative detection of circulating enterocytes using CGM2 RT-PCR assay provides no specific prognostic information and cannot be used as a decision criterion for adjuvant therapy.

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.

Alterations of APC, c-met, and p53 genes in tumor tissue and serum of patients with gastric cancers

BACKGROUND

Gastric cancer is one of the most significant causes of cancer-related death worldwide. A genetic model consisting of sequential accumulations of alterations in specific genes for gastric cancer has been proposed.

MATERIALS AND METHODS

The significance of adenomatous polyposis coli (APC) and p53 gene mutations in cancer tissues and their paired serum of 34 gastric cancer patients was investigated using polymerase chain reaction single-strand conformation polymorphism analysis (PCR-SSCP), followed by direct sequencing. c-met mRNA expression was evaluated by reverse-transcription PCR (RT-PCR). Additionally, analyses were carried out to detect the serum carcinoembryonic antigen (CEA) levels, and their correlation to these three molecular markers. Finally, serum molecular markers and their correlation to the presence of postoperative recurrence/metastasis were analyzed.

RESULTS

Of all, 32.4% of patients presented mutations in APC and p53, respectively, and 58.8% presented the overexpression in c-met, overall, at least one of these genetic alterations in 79.4% of tumor tissues. Comparison of three molecular markers showed that the individual detection rate in the serum of patients with tumors harboring the same abnormalities was 18.2, 70.0, and 36.4% for APC, c-met, and p53 genes, respectively. In general, 59.3% of serum from cancerous tissues with gene alterations was demonstrated as positive, whereas all healthy volunteers' sera remained negative. Regarding gene alterations in tumor tissues, c-met overexpression was significantly related to the tumor size (P = 0.017), depth of tumor invasion (P = 0.007), lymph-node metastasis (P < 0.001), and TNM stage (P = 0.001). In the serum, c-met overexpression was closely associated with lymph-node metastasis (P = 0.008) and TNM stage (P = 0.016). The overall positive tumor gene detection rate in the serum was prominently correlated to the serum CEA levels (P = 0.038). In addition, a significantly higher postoperative metastasis/recurrence rate in patients harboring gene mutations with serum molecular markers than those without serum molecular markers was also demonstrated (P = 0.014).

CONCLUSIONS

Our findings suggest that serum molecular markers can be detected in a substantial proportion of gastric cancer patients, and these may offer an auxiliary approach in the noninvasive detection and prognosis of gastric cancer.

Molecular detection of APC, K- ras, and p53 mutations in the serum of colorectal cancer patients as circulating biomarkers

Early detection of tumor DNA in serum/plasma prior to the development of recurrence or metastases could help improve the outcome of patients with colorectal cancer (CRC) after tumor resection. Recent advances in the detection of tumor DNA in the serum/plasma has opened up numerous new areas for investigation and new possibilities for molecular diagnosis. APC and K- ras mutations are considered to be early-stage developments of CRCs, whereas p53 mutations are thought to be relatively late events in the tumorigenesis of CRCs. The aim of this study was to search for the presence of genetic mutations in the DNA extracted from the serum of CRC patients and healthy subjects. We simultaneously evaluate the significance of APC, K- ras, and p53 gene mutations in cancer tissues and their paired serum samples of 104 CRC patients by polymerase chain reaction-single strand conformation polymorphism analysis (PCR-SSCP) followed by direct sequencing. Additionally, analysis was carried out to detect the serum carcinoembryonic antigen (CEA) levels in CRC patients. Overall, we found at least one of the gene mutations in tumor tissues from 75% (78/104) of the CRC patients. Comparison of the three molecular markers showed that the detection rates in the serum were 30.4%, 34.0%, and 34.2% for APC, K- ras, and p53 genes, respectively. Of these patients, 46.2% (36/78) were identified as having positive serum results, whereas all healthy controls remained negative. The overall positive tumor DNA detection rates in the serum were 0% (0/7) for Dukes' A classification, 22.4% (11/49) for Dukes' B, 48.7% (19/39) for Dukes' C, and 66.7% (6/9) for Dukes' D. The detection rate increased as the tumor stage progressed ( p = 0.012). Concurrently, a significant difference was observed between lymph node metastases and positive serum tumor DNA detection ( p < 0.001). A significantly higher postoperative metastasis/recurrence rate in patients harboring gene mutations with serum tumor DNA than those without serum tumor DNA was also demonstrated ( p < 0.001). However, no significant correlation between the postoperative metastasis/recurrence and serum CEA levels was observed ( p = 0.247). These data suggest that the identification of circulating tumor DNA using the molecular detection of APC, K- ras, and p53 gene mutations is a potential tool for early detection of postoperative recurrence/metastases. Moreover, these genes may be potential molecular markers of poor clinical outcome in CRC patients.

Colon cancer: prevalence, screening, gene expression and mutation, and risk factors and assessment

Colon cancer detection at an early stage and identifying susceptible individuals can result in reduced mortality from this prevalent cancer. Genetic events leading to the development of this cancer involve a multistage progression of adenoma polyps to invasive metastatic carcinomas. Currently, there is no satisfactory screening method that is highly specific, sensitive, or reliable. Dietary patterns associated with the greatest increase in colon cancer risk are the ones that typify a diet rich in fat and calories, and low in vegetable, fruits, and fibers. Genetic susceptibility to environmental carcinogenesis must be factored into the risk assessment for this cancer. Many genes have been shown to be associated with increased expression and mutations in colorectal cancer patients. These genes have been reviewed; it is hoped that by carefully selecting a number of them, a molecular approach that is suitable for arriving at a tumorigenic expression index is developed, which will reliably detect this cancer at an early stage (i.e., before it metastasizes), especially in exfoliated samples (e.g., stool and blood), so that appropriate intervention strategies can be implemented. Illustrated herein is the utility of employing real-time reverse transcriptase polymerase chain reaction (RT-PCR) to quantitatively measure gene expression, and develop an index that is specific for this cancer, which if perfected may result in a reliable and sensitive screening technique for colorectal cancer detection.