Cytokeratins and carcinoembryonic antigen in diagnosis, staging and prognosis of colorectal adenocarcinoma

Grape seed oil attenuates sodium arsenite-induced gastric, hepatic and colonic damage in Wistar rats

Arsenic exposure is associated with numerous morbidities due to dysfunction of various organ systems including the gastrointestinal tract. We investigated the protective effect of grape seed oil (GSO) against sodium arsenite (NaAsO2)-induced gastric, hepatic and colonic injuries in rats. Twenty-four male Wistar rats were divided into four groups of six as follows: Group A (control) received saline; group B received NaAsO2 (2.5 mg/kg) orally for 7 days; group C were treated concurrently with NaAsO2 and GSO (2 ml/kg), while group D received only GSO. Administration of NaAsO2 induced significant (p < 0.05) increases in alanine aminotransferase (ALT) and aspartate aminotransferase (AST); increased periodic acid Schiff (PAS) staining for mucus and increased goblet cell numbers in the stomach and colon; inflammatory cell infiltration and vascular congestion and alterations in the fecal bacterial flora. GSO supplementation generally promoted a reversal of changes induced by NaAsO2 towards control levels. Additionally, there was increased immunohistochemically detected expression of colonic B-cell lymphoma-1 (Bcl-2) and cytokeratins AE1/AE3, but reduced expression of mucin 1 (MUC1) and carcinoembryonic antigen (CEA) in NaAsO2 + GSO and GSO treated rats when compared with the NaAsO2 group. These results suggest that GSO promoted anti-inflammatory processes in the liver, stomach and colon, as well as opposing apoptosis in the colon, resulting in significant attenuation of damage to these tissues.

Identifying Novel Biomarkers Ready for Evaluation in Low-Prevalence Populations for the Early Detection of Lower Gastrointestinal Cancers: A Systematic Review and Meta-Analysis

INTRODUCTION

Lower gastrointestinal (GI) cancers are a major cause of cancer deaths worldwide. Prognosis improves with earlier diagnosis, and non-invasive biomarkers have the potential to aid with early detection. Substantial investment has been made into the development of biomarkers; however, studies are often carried out in specialist settings and few have been evaluated for low-prevalence populations.

METHODS

We aimed to identify novel biomarkers for the detection of lower GI cancers that have the potential to be evaluated for use in primary care. MEDLINE, Embase, Emcare and Web of Science were systematically searched for studies published in English from January 2000 to October 2019. Reference lists of included studies were also assessed. Studies had to report on measures of diagnostic performance for biomarkers (single or in panels) used to detect colorectal or anal cancers. We included all designs and excluded studies with fewer than 50 cases/controls. Data were extracted from published studies on types of biomarkers, populations and outcomes. Narrative synthesis was used, and measures of specificity and sensitivity were meta-analysed where possible.

RESULTS

We identified 142 studies reporting on biomarkers for lower GI cancers, for 24,844 cases and 45,374 controls. A total of 378 unique biomarkers were identified. Heterogeneity of study design, population type and sample source precluded meta-analysis for all markers except methylated septin 9 (mSEPT9) and pyruvate kinase type tumour M2 (TuM2-PK). The estimated sensitivity and specificity of mSEPT9 was 80.6% (95% CI 76.6-84.0%) and 88.0% (95% CI 79.1-93.4%) respectively; TuM2-PK had an estimated sensitivity of 81.6% (95% CI 75.2-86.6%) and specificity of 80.1% (95% CI 76.7-83.0%).

CONCLUSION

Two novel biomarkers (mSEPT9 and TuM2-PK) were identified from the literature with potential for use in lower-prevalence populations. Further research is needed to validate these biomarkers in primary care for screening and assessment of symptomatic patients.

The sensitivity and specificity of serum glycan-based biomarkers for cancer detection

Most of clinically used serum biomarkers for cancer detection were established in early 1980s when the Nobel Prize in physiology or medicine was awarded for the "discovery of the principle for the production of monoclonal antibodies." Using this "Nobel" technology, various monoclonal antibodies were obtained when different types of cancer cells were injected into mice and the ligands on the cancer cell surface were characterized. Both aberrant glycan structures and aberrant glycan-associated glycoproteins were revealed as a common feature of cancer cell surfaces through the specific interactions with the monoclonal antibodies. These results indicate that the biosynthesis of the environment-sensitive glycan structures goes awry in cancer cells, which is beyond genetic mutations. Later on, the glycan-related biomarkers were detected in the sera of cancer patients and then developed into serum biomarkers, such as CA125, CA153, CA195, CA199, CA242, CA27.29, CA50, and CA724, which are still in clinical use as of today. During the past 30 years, even with the advancement of different OMICS technologies not limited to genomics, epigenomics, proteomics, glycomics, lipidomics, and metabolomics, very few serum biomarkers have been introduced into clinical practice. The reason is that most of the newly discovered cancer biomarkers are inferior in terms of sensitivity and specificity to these biomarkers. We will summarize the reported sensitivity and specificity of currently used cancer biomarkers, especially the glycan-related biomarkers, in the forms of tables and radar plots and discuss the pros and cons of currently used cancer biomarkers.

Predictive performance of TPA testing for recurrent disease during follow-up after curative intent surgery for colorectal carcinoma

BACKGROUND

The aim of the present study was to investigate the predictive performance of serial tissue polypeptide antigen (TPA) testing after curative intent resection for detection of recurrence of colorectal malignancy.

METHODS

Serum samples were obtained in 572 patients from three different hospitals during follow-up after surgery. Test characteristics of serial TPA testing were assessed using a cut-off value of 75 U/L. The relation with American Joint Committee on Cancer stage and the potential additive value of tissue polypeptide antigen testing upon standard carcinoembryonic antigen (CEA) testing were investigated.

RESULTS

The area under the receiver operating characteristic curve of TPA for recurrent disease was 0.70, indicating marginal usefulness as a predictive test. Forty percent of cases that were detected by CEA testing would have been missed by TPA testing alone, whilst most cases missed by CEA were also not detected by TPA testing. In the subpopulation of patients with stage III disease predictive performance was good (area under the curve 0.92 within 30 days of diagnosing recurrent disease). In this group of patients, 86% of cases that were detected by CEA were also detected by TPA.

CONCLUSIONS

Overall, TPA is a relatively poor predictor for recurrent disease during follow-up. When looking at the specific subpopulation of patients with stage III disease predictive performance of TPA was good. However, TPA testing was not found to be superior to CEA testing in this specific subpopulation.

Applying Genomics and Proteomics in Translational Surgical Oncology Research

BACKGROUND

Translational surgical research can range from investigating clinically oriented basic pathophysiological research via the correlation of molecular findings with a patient's clinical outcome to conducting treatment response studies. Herein, the specialist's opinion as a 'surgeon scientist' plays a pivotal role, e.g. in planning experimental setups focusing on the clinically most relevant needs. SUMMARY AND KEY MESSAGES: This review provides a survey of genomic and proteomic technologies and gives an up-to-date overview of those studies applying these technologies exemplarily in colorectal cancer-based biomarker research. Although current results are promising, future validation studies within multicenter networks are required to promote the translation of 'omics' from bench to bedside. In this endeavor, departments of surgery and institutes of experimental surgery together should play a fundamental role. The program for 'clinician scientists' recently launched by the German Research Society (DFG) could be one tool to promote interdisciplinary networks and surgeons' impact on translational research.

Differential expression of colon cancer associated transcript1 (CCAT1) along the colonic adenoma-carcinoma sequence

BACKGROUND

The transition from normal epithelium to adenoma and, to invasive carcinoma in the human colon is associated with acquired molecular events taking 5-10 years for malignant transformation. We discovered CCAT1, a non-coding RNA over-expressed in colon cancer (CC), but not in normal tissues, thereby making it a potential disease-specific biomarker. We aimed to define and validate CCAT1 as a CC-specific biomarker, and to study CCAT1 expression across the adenoma-carcinoma sequence of CC tumorigenesis.

METHODS

Tissue samples were obtained from patients undergoing resection for colonic adenoma(s) or carcinoma. Normal colonic tissue (n = 10), adenomatous polyps (n = 18), primary tumor tissue (n = 22), normal mucosa adjacent to primary tumor (n = 16), and lymph node(s) (n = 20), liver (n = 8), and peritoneal metastases (n = 19) were studied. RNA was extracted from all tissue samples, and CCAT1 expression was analyzed using quantitative real time-PCR (qRT-PCR) with confirmatory in-situ hybridization (ISH).

RESULTS

Borderline expression of CCAT1 was identified in normal tissue obtained from patients with benign conditions [mean Relative Quantity (RQ) = 5.9]. Significant relative CCAT1 up-regulation was observed in adenomatous polyps (RQ = 178.6 ± 157.0; p = 0.0012); primary tumor tissue (RQ = 64.9 ± 56.9; p = 0.0048); normal mucosa adjacent to primary tumor (RQ = 17.7 ± 21.5; p = 0.09); lymph node, liver and peritoneal metastases (RQ = 11,414.5 ± 12,672.9; 119.2 ± 138.9; 816.3 ± 2,736.1; p = 0.0001, respectively). qRT-PCR results were confirmed by ISH, demonstrating significant correlation between CCAT1 up-regulation measured using these two methods.

CONCLUSION

CCAT1 is up-regulated across the colon adenoma-carcinoma sequence. This up-regulation is evident in pre-malignant conditions and through all disease stages, including advanced metastatic disease suggesting a role in both tumorigenesis and the metastatic process.

A novel multiplex-protein array for serum diagnostics of colon cancer: a case-control study

BACKGROUND

More than 1.2 million new cases of colorectal cancer are reported each year worldwide. Despite actual screening programs, about 50% of the patients are diagnosed at advanced tumor stages presenting poor prognosis. Innovative screening tools could aid the detection at early stages and allow curative treatment interventions.

METHODS

A nine target multiplex serum protein biochip was generated and evaluated using a training- and validation-set of 317 highly standardized, liquid nitrogen preserved serum samples comprising controls, adenomas, and colon cancers.

RESULTS

Serum levels of CEA, IL-8, VEGF, S100A11, MCSF, C3adesArg, CD26, and CRP showed significant differences between cases and controls. The largest areas under the receiver operating characteristics curve were observed for CEA, IL-8, and CRP. At threshold levels yielding 90% specificity, sensitivities for CEA, IL-8 and CRP were 26%, 22%, and 17%, respectively. The most promising marker combinations were CEA + IL-8 reaching 37% sensitivity at 83% specificity and CEA + CRP with 35% sensitivity at 81% specificity. In an independent validation set CEA + IL-8 reached 47% sensitivity at 86% specificity while CEA + CRP obtained 39% sensitivity at 86% specificity. Early carcinomas were detected with 33% sensitivity for CEA + IL-8 and 28% for CEA + CRP.

CONCLUSIONS

Apart from CEA, IL-8, and CRP, the screening value of additional blood markers and the potential advantage of combining serum biochip testing with fecal occult blood testing needs to be studied. Multiplex biochip array technology utilizing serum samples offers an innovative approach to colorectal cancer screening.

Screening for colorectal cancer: established and emerging modalities

It has been estimated that >95% of cases of colorectal cancer (CRC) would benefit from curative surgery if diagnosis was made at an early or premalignant polyp stage of disease. Over the past 10 years, most developed nation states have implemented mass population screening programs, which are typically targeted at the older (at-risk) age group (>50-60 years old). Conventional screening largely relies on periodic patient-centric investigation, particularly involving colonoscopy and flexible sigmoidoscopy, or else on the fecal occult blood test. These methods are compromised by either low cost-effectiveness or limited diagnostic accuracy. Advances in the development of diagnostic molecular markers for CRC have yielded an expanding list of potential new screening modalities based on investigations of patient stool (for colonocyte DNA mutations, epigenetic changes or microRNA expression) or blood specimens (for plasma DNA mutations, epigenetic changes, heteroplasmic mitochondrial DNA mutations, leukocyte transcriptome profile, plasma microRNA expression or protein and autoantibody expression). In this Review, we present a critical evaluation of the performance data and relative merits of these various new potential methods. None of these molecular diagnostic methods have yet been evaluated beyond the proof-of-principle and pilot-scale study stage and it could be some years before they replace existing methods for population screening in CRC.

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.

Reference intervals for serum alpha-fetoprotein and carcinoembryonic antigen in Chinese Han ethnic males from the Fangchenggang Area Male Health and Examination Survey

OBJECTIVES

We calculated upper 95% reference limits for serum alpha-fetoprotein (AFP) and carcinoembryonic antigen (CEA) according to the CLSI/NCCLS C28-A3 guideline.

MATERIAL AND METHODS

Serum samples from 1400 healthy male subjects were collected from the Fangchenggang Area Male Health and Examination Survey (FAMHES). Serum AFP and CEA values were measured by electrochemiluminescence immunoassay on COBAS 6000 system E601 (Elecsys module) immunoassay analyzers.

RESULTS

Serum AFP and CEA values were not normally distributed but log normally distributed. The upper 95% reference limits of the reference intervals were ≤ 4.76 IU/mL (nonparametric) or ≤ 4.56 IU/mL (parametric) for AFP and ≤ 5.57 ng/mL (nonparametric) or ≤ 5.82 ng/mL (parametric) for CEA. The distribution of AFP levels was found to be consistent between the non-smoking and smoking (p=0.740) and non-drinking and drinking groups (p=0.698). The distribution of serum CEA levels was significantly higher in the smoking than the non-smoking group (p<10⁵), whereas there was no significant difference in this respect between the non-drinking and drinking groups (p=0.147). A significant increase with age was found both for serum AFP and CEA levels, and the age-dependent reference intervals were calculated.

CONCLUSIONS

The reference intervals for serum AFP and CEA show a slight deviation compared to previously reported reference levels. Distinct reference intervals of serum CEA must be established for smoking and non-smoking populations. In addition, age-dependent reference intervals should be implemented in clinical laboratories.

Potential of soluble CD26 as a serum marker for colorectal cancer detection

Colorectal cancer is characterized by a low survival rate even though the basis for colon cancer development, which involves the evolution of adenomas to carcinoma, is known. Moreover, the mortality rates continue to rise in economically transitioning countries although there is the opportunity to intervene in the natural history of the adenoma–cancer sequence through risk factors, screening, and treatment. Screening in particular accounted for most of the decline in colorectal cancer mortality achieved in the USA during the period 1975-2000. Patients show a better prognosis when the neoplasm is diagnosed early. Among the variety of screening strategies, the methods range from invasive and costly procedures such as colonoscopy to more low-cost and non-invasive tests such as the fecal occult blood test (guaiac and immunochemical). As a non-invasive biological serum marker would be of great benefit because of the performance of the test, several biomarkers, including cytologic assays, DNA and mRNA, and soluble proteins, have been studied. We found that the soluble CD26 (sCD26) concentration is diminished in serum of colorectal cancer patients compared to healthy donors, suggesting the potential utility of a sCD26 immunochemical detection test for early diagnosis. sCD26 originates from plasma membrane CD26 lacking its transmembrane and cytoplasmic domains. Some 90%–95% of sCD26 has been associated with serum dipeptidyl peptidase IV (DPP-IV) activity. DPP-IV, assigned to the CD26 cluster, is a pleiotropic enzyme expressed mainly on epithelial cells and lymphocytes. Our studies intended to validate this test for population screening to detect colorectal cancer and advanced adenomas are reviewed here.

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.

Relationship between peripheral and mesenteric serum levels of CEA and CA 242 with staging and histopathological variables in colorectal adenocarcinoma

PURPOSE

To compare histopathological variables and staging in colorectal adenocarcinoma cases with CEA and CA 242 in peripheral and mesenteric blood.

METHODS

In 169 individuals underwent surgery for colorectal cancer, CEA and CA 242 were analyzed and compared to mesenteric and peripheral blood and correlated with macroscopic tumor's morphology and size, degree of cell differentiation, venous, neural and lymphatic involvement and TNM classification.

RESULTS

There was a difference between the mesenteric (M) and peripheral (P) serum levels of CEA (p=0.020). Higher levels of markers were correlated with venous invasion CEA (P) p=0.013, CEA (M) p=0.05, CA 242 (M) p=0.005 and CA 242 (P) p=0.038; with advanced staging CEA (P) < CEA (M) (p < 0.05); CA 242 (P) < CA 242 (M) (p < 0.05); and with greater dimensions CEA (P) < CEA (M) (p < 0.001); CA 242 (P) < CA 242 (M) (p < 0.001). CA 242 became higher with neural invasion (P): p=0.014, (M): p=0.003).

CONCLUSIONS

There were higher mesenteric than peripheral levels of CEA. Both mesenteric and peripheral levels of CEA and CA 242 were higher in neoplasm with venous involvement, greater diameter and advanced stages. There was a correlation between CA 242 and neural invasion.

Peripheral and mesenteric serum levels of CEA and cytokeratins, staging and histopathological variables in colorectal adenocarcinoma

AIM: To evaluate the differences that exist bet-ween peripheral and mesenteric serum levels of carcinoembryonic antigen (CEA) and cytokeratins in patients with colorectal adenocarcinoma.

METHODS: One hundred and thirty-eight patients with colorectal adenocarcinoma who underwent surgery at Hospital São Paulo (Discipline of Surgical Gastroenterology of UNIFESP-EPM) between December 1993 and March 2000 were retrospectively analyzed. Differences between CEA and cytokeratin (TPA-M) levels in peripheral blood (P) and in mesenteric blood (M) were studied. Associations were investigated between peripheral and mesenteric levels and the staging and histopathological variables (degree of cell differentiation, macroscopic appearance, tumor dimensions and presence of lymphatic and venous invasion).

RESULTS: Differences were observed in the numerical values of the marker levels: CEA (M) (39.10 mg/L ± 121.19 mg/L) vs CEA (P) (38.5 mg/L ± 122.55 mg/L), P < 0.05; TPA-M (M) (325.06 U/L ± 527.29 U/L) vs TPA-M (P) (279.48 U/L ± 455.81 U/L), P < 0.01. The mesenteric CEA levels were higher in more advanced tumors (P < 0.01), in vegetating lesions (34.44 mg/L ± 93.07 mg/L) (P < 0.01) and with venous invasion (48.41 mg/L ± 129.86 mg/L) (P < 0.05). Peripheral CEA was higher with more advanced staging (P < 0.01) and in lesions with venous invasion (53.23 mg/L ± 158.57 mg/L) (P < 0.05). The patients demonstrated increased mesenteric and peripheral TPA-M levels with more advanced tumors (P < 0.01 and P < 0.01) and in non-ulcerated lesions [530.45 U/L ± 997.46 U/L (P < 0.05) and 457.95 U/L ± 811.36 U/L (P < 0.01)].

CONCLUSION: The mesenteric levels of the tumor markers CEA and cytokeratins were higher than the peripheral levels in these colorectal adenocarcinoma patients. Higher levels of these biologic tumor markers are associated with an advanced state of cancerous dissemination.

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.

Free DNA and carcinoembryonic antigen serum levels: an important combination for diagnosis of colorectal cancer

PURPOSE

The identification of new molecular markers for the early detection of colorectal cancer has become an important objective. We compared the sensitivity and specificity of free circulating DNA with that of the more conventional carcinoembryonic antigen (CEA) and evaluated the two markers in combination.

EXPERIMENTAL DESIGN

The study was carried out on 75 healthy donors and 75 colorectal cancer patients. Free DNA was determined in serum with quantitative PCR analysis. The diagnostic accuracy of each assay was calculated using receiver operating characteristic (ROC) curves. The diagnostic relevance of the two-marker combination was analyzed by the logistic regression model.

RESULTS

Median free DNA concentration was approximately 5-fold higher in patients than in healthy donors (P < 0.001). The area under the ROC curve was 0.86, and when 12.5 ng/mL was used as cutoff, 81.3% sensitivity and 73.3% specificity were observed for the overall series. As CEA and free DNA provided independent diagnostic information, they were also considered in combination. ROC curve analysis of the combined CEA and free DNA algorithms showed a higher diagnostic capacity (area under the ROC curve, 0.92) than that of markers considered singly, with 84% sensitivity and 88% specificity.

CONCLUSIONS

Free circulating DNA, especially when used in combination with CEA, represents a potentially useful tool for the diagnosis of early-stage colorectal cancer.

Significance of CEA and VEGF as Diagnostic Markers of Colorectal Cancer in Lebanese Patients

Carcinoembryonic antigen and vascular endothelial growth factors are among the most important prognostic markers of colorectal cancer. Testing for these markers independently has been of limited value in screening for this tumor. The aim of this study is to determine the importance of simultaneous blood CEA and VEGF level determinations in diagnosis of colorectal cancer. Thirty-six patients diagnosed with colorectal cancer along with eight healthy controls were tested by ELISA for CEA and VEGF levels in serum and plasma, respectively. The positive predictive value of these markers was 95.4% for CEA and 89.5% for VEGF, and for combined CEA and VEGF was also high at 88%. Combined CEA and VEGF blood level assay constitutes a useful panel in detecting patients with colorectal cancer. Positive results allow selection of a subgroup of patients with a high tumor risk; therefore, such tests comprise valuable tumor diagnostic tests to add to current detection methods.

Circulating nucleic acids in plasma/serum

Since the discovery of circulating nucleic acids in plasma in 1948, many diagnostic applications have emerged. For example, diagnostic and prognostic potentials of circulating tumour-derived DNA have been demonstrated for many types of cancer. The parallel development of fetal-derived DNA detection in maternal plasma has opened up the possibility of non-invasive prenatal diagnosis and monitoring of many pregnancy-associated disorders. In this regard, non-invasive fetal rhesus blood group genotyping has already been translated to clinical practice. Other applications of circulating DNA in traumatology and transplant monitoring have also been reported. The more recent discoveries of circulating tumour-derived RNA and fetal-derived RNA have proven to be equally important as their DNA counterparts. Successful prenatal diagnosis of Down's syndrome by fetal RNA analysis has recently been reported. However, the definite origin and release mechanisms of circulating nucleic acids have remained incompletely understood, with cell death being suggested to be associated with such nucleic acid release. Pre-analytical standardisation will become increasingly relevant when comparing data from different laboratories. In conclusion, studies of circulating nucleic acids have promised exciting developments in molecular diagnostics in the years to come.

Value of carcinoembryonic antigen and cytokeratins for the detection of recurrent disease following curative resection of colorectal cancer

AIM: To evaluate the efficacy of postoperative serial assay of carcinoembryonic antigen (CEA) and cytokeratins for the detection of recurrent disease in patients with colorectal adenocarcinoma after radical surgery.

METHODS: Between 1993 and 2000, 120 patients with colorectal adenocarcinoma underwent radical surgery in the Department of Surgical Gastroenterology, Federal University of São Paulo-Escola Paulista de Medicina, São Paulo, Brazil. Periodic postoperative evaluation was performed by assaying markers in peripheral serum, colonoscopy and imaging examination. Presence of CEA was detected using the Delfia^® method with 5 μg/L threshold, and cytokeratins using the LIA-mat^® TPA-M Prolifigen^® method with 72 U/L threshold.

RESULTS: In the first postoperative year, patients without recurrent disease had normal levels of CEA (1.5 ± 0.9 μg/L) and monoclonal tissue polypeptide antigen-M (TPA-M, 64.4 ± 47.8 U/L), while patients with recurrences had high levels of CEA (6.9 ± 9.8 μg/L, P < 0.01) and TPA-M (192.2 ± 328.8 U/L, P < 0.05). During the second postoperative year, patients without tumor recurrence had normal levels of CEA (2.0 ± 1.8 μg/L) and TPA-M (50.8 ± 38.4 U/L), while patients with recurrence had high levels of CEA (66.3 ± 130.8 μg/L, P < 0.01) and TPA-M (442.7 ± 652.8 U/L, P < 0.05). The mean follow-up time was 22.3 mo. There was recurrence in 23 cases. Five reoperations were performed without achieving radical excision. Rises in tumor marker levels preceded identification of recurrences: CEA in seven (30%) and TPA-M in eleven individuals (48%).

CONCLUSION: Intensive follow-up by serial assay of CEA and cytokeratins allows early detection of colorectal neoplasm recurrence.

Comparison between time-resolved fluorescence immunoassay and electro-chemiluminescence immunoassay for detection of serum carcinoembryonic antigen in colorectal carcinoma

AIM: To evaluate the effect of time-resolved fluorescen-ce immunoassay (TRFIA) and electro-chemilumines-cence immunoassay (ECLIA) for detecting the serum level of carcinoembryonic antigen (CEA) and their influ-ence on the positive rate of serum CEA in patients with colorectal carcinoma.

METHODS: Serum CEA levels were detected with both TRFIA and ECLIA in 90 samples from patients with colorectal carcinoma (n = 30), non-colorectal car-cinoma (n = 30), and the healthy controls (n = 30). The data were analyzed with statistical software SPSS.

RESULTS: The level of CEA was significantly higher in the colorectal cancer group (TRFIA: 44.12±95.27 μg/L, ECLIA: 35.96±71.83 μg/L) than that in the heal-thy control group (TRFIA: 1.04±0.55 μg/L, ECLIA: 0.71±0.48 μg/L) (P <0.01). The sensitivities of TRFIA and ELCIA were 60.0% and 66.7%; the specificities were 98.3% and 100%; the accuracies were 85.6% and 88.9%; the positive predictive rates were 94.7% and 95.2%; and the negative predictive rates were 83.1% and 85.7%, respectively. The results of ELCIA were better than those of the TRFIA, and they were well correlated (r = 0.973 8). There was no significant difference between the two methods (P >0.05).

CONCLUSION: Qingre Huashi recipe can increase the expression of LDL-R mRNA in the liver tissues of rat model of dampness-heat syndrome.