Clinical utility of biochemical markers in colorectal cancer: European Group on Tumour Markers (EGTM) guidelines

Colorectal carcinoma: nucleosomes, carcinoembryonic antigen and ca 19-9 as apoptotic markers; a comparative study

Background

Colorectal carcinoma is a common and often fatal disease in which methods of early detection and monitoring are essential. The present study was conducted for measuring serum levels of nucleosomes, carcinoembryonic antigen (CEA) and CA 19-9 in patients newly diagnosed with colorectal carcinoma and confirmed by clinicopathological study.

Method

Thirty subjects were included in the current study: six normal subjects as a control group with mean age (45.6 ± 7.9) and twenty four colorectal carcinoma patients with mean age (46.9 ± 15.6), which were classified pathologically according to the degree of malignant cell differentiation into well differentiated (group I), moderately differentiated (group II) and poorly differentiated (group III). Fasting venous blood samples were collected preoperative.

Results

The results revealed a significant increase in serum level of nucleosomes in patients with poorly differentiated tumors versus patients with well differentiated tumors (p = 0.041). The levels of CEA and CA19-9 showed no significant increase (p = 0.569 and 0.450, respectively).

Conclusion

In conclusion, serum level of nucleosomes provides a highly sensitive and specific apoptotic marker for colorectal carcinoma.

Screening options and recommendations for colorectal cancer

Screening reduces the burden of disease from colorectal cancer through early detection of cancerous lesions and removal of precancerous polyps. The ideal colorectal cancer screening modality should be cost-effective, increase life-years gained, permit long intervals between tests with high patient compliance and low risk to the patient. Although no single colorectal cancer screening method is perfect, several options exist. Government agencies and medical societies have published screening recommendations with differing guidelines; yet, despite the lack of a consistent standard, it is clear that colorectal cancer screening is cost-effective. In this review, the authors address several options for screening, identify risks and benefits, and present methods to risk stratify patients. A thorough discussion with the patient about potential benefits and harms is critical before initiating any screening regimen.

Use of multiple reaction monitoring for multiplex analysis of colorectal cancer-associated proteins in human feces

Colorectal cancer (CRC) is the second most common cause of cancer-related deaths worldwide with an annual incidence of almost a million cases and an annual mortality around 500,000. The fecal occult blood test is currently the first line method for CRC screening, but has unacceptably low sensitivity and specificity. Improved screening tests are therefore urgently required for early-stage CRC screening when therapy is most likely to be effective. We describe a discovery-based proteomics hypothesis using orthogonal multi-dimensional fractionation (1-D SDS-PAGE, RP-HPLC, size exclusion chromatography) to mine deep into the fecal proteome for the initial discovery process, which generated a library containing 108 human fecal proteins with the associated peptide and MS/MS data. These data were then used to develop and optimize a multiplex multiple reaction monitoring assay for 40 non-redundant human proteins present in the feces. To show proof of principal for clinical analysis, multiplex screening of these 40 proteins was carried out on fecal samples from eight CRC patient and seven normal volunteers. We identified 24 proteins consistently found in all samples and nine proteins found only in the CRC patients, showing the potential of this approach for the analysis of potential CRC biomarkers. Absolute quantitation using C-terminal isotopically labeled synthetic peptides corresponding to hemoglobin and carcinoembryonic antigen 5 was also performed.

EPAS1 mRNA in plasma from colorectal cancer patients is associated with poor outcome in advanced stages

The presence of free nucleic acids in plasma has been detected in cancer patients and is associated with poor prognosis. In the present study, the mRNA levels of three genes (EPAS1, KIAA0101 and UBE2D3) in plasma from colorectal cancer patients were analyzed. These genes were selected from a previous study of genomic profiles, discriminating between healthy controls and colorectal cancer patients. mRNA levels were analyzed by real-time PCR in the plasma of 154 patients with colorectal cancer. The association of plasma mRNA levels with clinicopathological parameters and patient survival were analyzed. High levels of EPAS1 in the plasma were associated with patients aged over 50 years, relapse of disease and patient mortality. When patients were divided into two groups, early (I and II) and advanced (III and IV) stages, an association was observed between high levels of EPAS1 mRNA and worse disease-free and overall survival in advanced stages. The expression of KIAA0101 and UBE2D3 was not associated with poor prognosis. Thus, our results suggest that EPAS1 mRNA levels may be an indicator of poor prognosis in colorectal cancer patients at advanced stages, obtained by a non-invasive method.

Identification of biomarkers to improve diagnostic sensitivity of sporadic colorectal cancer in patients with low preoperative serum carcinoembryonic antigen by clinical proteomic analysis

BACKGROUND

Colorectal cancer (CRC) is the third most common type of cancer worldwide. Carcinoembryonic antigen (CEA) assays usually give false negative results. To improve the diagnosis of primary sporadic CRC, there is an urgent need to identify new biomarkers.

METHODS

We used laser pressure catapulting and proteomics to analyze overexpressed cancer associated proteins from 48 sporadic CRC patients with low preoperative serum CEA (LPSC) (<5 ng/ml). Real-time Q-PCR was used to identify the target gene transcripts. Immunoblots were carried out to validate the biomarkers.

RESULTS

Alpha-enolase, HSP27 and macrophage migration inhibitory factor (MIF) were overexpressed in all tumor tissues from 48 LPSC CRC patients, as assessed by 2DE image analysis. The genes were also overexpressed at the transcript level in all tumor tissues from the same patients. In the immunoblot assay, only serum levels of Alpha-enolase and MIF were significantly overexpressed in the LPSC group compared to the mean levels in the control group. Combined with the determinations of preoperative CEA levels, screening for serum Alpha-enolase and MIF were shown to improve the diagnosis of primary CRC.

CONCLUSIONS

Serum Alpha-enolase and MIF may be potential biomarkers that can be used to improve clinical predication of primary CRC with LPSC.

Serum protein fingerprinting for diagnosis and prognosis evaluation of colorectal cancer

AIM: To identify differentially expressed proteins for diagnosis and prognosis evaluation of colorectal cancer by serum protein fingerprint in colorectal cancer patients.

METHODS: Serum protein fingerprinting was performed by surface-enhanced laser desorption ionization time-of-flight mass spectrometry (SELDI-TOF-MS) in 45 colorectal cancer patients, 14 colorectal cancer having a good prognosis (no postoperative recurrence and metastasis), 13 colorectal cancer patients having a poor prognosis (having recurrence or metastasis), 24 patients with benign gastrointestinal disease, and 155 healthy controls. The Biomarker Wizard software was used to identify differential proteins. Two respective artificial neural network (ANN) models were developed for diagnosis and prognosis evaluation of colorectal cancer.

RESULTS: Seven proteins that displayed significant differential expression were identified (all P < 0.01), and their molecular weight was 4 955 Da, 5 325 Da, 5 890 Da, 6 615 Da, 7 739 Da, 8 109 Da, and 8 575 Da, respectively. Using these seven protein markers, we developed an artificial neural network model for diagnosis of colorectal cancer. Furthermore, five proteins that had a molecular weight of 4 955 Da, 5 325 Da, 5 890 Da, 6 615 Da, and 7 739 Da were used to develop an artificial neural network model for evaluation of the prognosis of colorectal cancer. The sensitivity, specificity, negative predictive value, positive predictive value, and accuracy of the diagnostic model were 82.22%, 80.45%, 94.74%, 51.39% and 80.80%, respectively. The coincidence rate of the prognostic model for evaluation of recurrence and metastasis was 62.96%.

CONCLUSION: SELDI-TOF-MS serum protein fingerprinting allows identification of differentially expressed proteins in colorectal cancer to develop models for diagnosis and prognosis evaluation of the disease.

The discovery and validation of colorectal cancer biomarkers

Colorectal cancer is currently the third most common malignancy in the world. Patients have excellent prognosis following surgical resection if their tumour is still localized at diagnosis. By contrast, once the tumour has started to metastasize, prognosis is much poorer. Accurate early detection can therefore significantly reduce the mortality from this disease. However, current tests either lack the required sensitivity and selectivity or are costly and invasive. Improved biomarkers, or panels of biomarkers, are therefore urgently required. We have addressed current screening strategies and potential protein biomarkers that have been proposed. The role of both discovery and hypothesis-driven proteomics approaches for biomarker discovery and validation is discussed. Using such approaches we show how multiple reaction monitoring (MRM) can be successfully developed and used for quantitative multiplexed analysis of potential faecal biomarkers.

Serological diagnostic factors for liver metastasis in patients with colorectal cancer

AIM: To investigate the serological diagnostic factors for liver metastasis in patients with colorectal cancer.

METHODS: One hundred and six adult in-patients with colorectal cancer were studied and divided into patients with liver metastasis (n = 56) and patients without liver metastasis (n = 50). Serum levels of tumor and biochemical markers for liver were measured at the time of diagnosis.

RESULTS: The mean survival time was 55.9 mo, 36.8 mo and 68.3 mo for the overall patients, patients with liver metastasis and patients without liver metastasis, respectively. Lactate dehydrogenase (LDH) level was significantly correlated with the survival time of colorectal cancer patients. The levels of alanine aminotransferase, aspartate aminotransferase, γ-glutamyltransferase (GGT), LDH and carcinoembryonic antigen (CEA) were significantly higher in patients with liver metastasis than in those without liver metastasis. Patients with lymph node metastasis had a higher risk of liver metastasis than those without lymph node metastasis. The cut points of LDH, GGT and CEA for screening liver metastasis were 180 U/L, 30 U/L and 5.0 μg/L, respectively. The sensitivity was 64.3%, 69.6% and 70.4%, and the specificity was 64.0%, 60.0% and 52.4%, respectively. The sensitivity of parallel test was 85.2% for LDH and CEA, and 92.6% for GGT and CEA, respectively. The specificity of serial test was 85.7% for LDH (or GGT) and CEA.

CONCLUSION: Early diagnosis of liver metastasis is of great significance. The sensitivity and specificity of combined tumor and biochemical markers are rather good in screening colorectal liver metastasis.

Negative prognostic factors in colorectal carcinoma: An analysis of 448 patients

BACKGROUND AND AIMS

Colorectal carcinoma (CRC) is the most frequent malignancy of the gastrointestinal tract. Prognostic researches are carried out for choosing the optimum therapy, evaluating therapy results and comparing multicentre results for better qualification in the therapy of the disease.

PATIENTS AND METHODS

In this study, 448 patients, whose surgery and follow-up was performed by the same correspondent surgeon between the years 1995 and 2003, were retrospectively analyzed.

RESULTS

Age, presence of comorbidity, weight loss, emergency admission, high serum CEA and CA 19-9 levels, neighboring organ invasion, operation type, major morbidity, tumor size and type, lymph node metastases, venous and perineural invasion, Dukes' classification and local recurrence and distant metastasis during follow-up are found to be significant negative factors affecting prognosis of the CRC patient.

CONCLUSION

Therapy results of the CRC are evaluated by survival times regardless of the therapy method selected for each individual. In our study we tried to find out negative prognostic factors by researching possible factors affecting disease free survival time for CRC. Since our understanding of factors that have an impact on prognosis increases, we are hoping to improve survival.

Significance of vascular endothelial growth factor, interleukin-18 and nitric oxide in patients with breast cancer: correlation with carbohydrate antigen 15.3

The aim of this study was to determine serum concentrations of angiogenic factors including vascular endothelial growth factor (VEGF), interleukin 18 (IL-18) and nitric oxide (NO) in patients with breast cancer and to evaluate whether these factors will be correlated with CA 15.3, as a routine tumor marker for breast cancer or not. This study was conducted on 44 patients with breast cancer and 15 healthy individuals as a control group. The results demonstrated significant increase in serum IL-18, NO and CA 15.3 levels in sera of breast cancer patients when compared to those of the control group (P < 0.001, P = 0.016 and P < 0.001, respectively). However, the mean serum level of VEGF in patients as showed insignificant increase compared to that of the controls was not significant (P = 0.311). Sensitivity of CA 15.3, VEGF, IL-18 and NO to detect patients with disease was 52.2, 21.3, 77.2 and 70.4 %, respectively. In addition, positive status of serum CA 15.3 and/or IL-18 was found in 39 out of 44 (88.6 %) patients, and the positive status of serum CA 15.3 and/or NO was only found in 35 out of 44 (79.5 %). In conclusion, the simultaneous determination of IL-18 or NO in combination with the CA 15.3 may increase the sensitivity to diagnose breast cancer and may aid in disease prognosis.

Does serum carcinoembryonic antigen elevation in patients with postoperative stage II colorectal cancer indicate recurrence? Comparison with stage III

BACKGROUND AND OBJECTIVES

The aim of this study was to determine the accuracy of postoperative monitoring of serum carcinoembryonic antigen (CEA) to detect or rule out recurrence in patients with stage II colorectal cancer (CRC) by comparing results with stage III.

METHODS

A total of 303 patients with CRC who underwent curative surgery were enrolled. Serum CEA was assayed, and radiological examination was performed routinely for 5 years after surgery. Yearly recurrence rates, sensitivities, specificities, likelihood ratios, and posttest probabilities were calculated.

RESULTS

Sensitivity and specificity of CEA monitoring in stage II patients are almost same as those in stage III. Whereas recurrences occurred early in stage III, they occurred almost as frequently in both early and late stage II. The obtained posttest probability of recurrence in stage II patients with CEA elevation was significantly lower (only 30% or less) than those in stage III (approximately 80%).

CONCLUSION

Elevation of CEA in patients with stage II CRC does not represent recurrence with high probability. One of the reasons for the unreliability of CEA monitoring was its high false-positive rate. Another tumor marker with a lower false-positive rate is necessary to follow-up stage II CRC patients.

Combined analysis of survivin autoantibody and carcinoembryonic antigen biomarkers for improved detection of colorectal cancer

BACKGROUND

Survivin is a member of the family of inhibitor of apoptosis proteins that is overexpressed in several human tumors. Previous studies have found that overexpression of survivin in cancer cells induces an antibody response.

METHODS

We compared 232 serum samples from colorectal cancer (CRC) patients and 365 samples from healthy volunteers using an in vitro enzyme-linked immunosorbent assay to evaluate the survivin autoantibody response in patients.

RESULTS

The sensitivity of the anti-survivin response from patients with CRC was 56.9%, and the specificity was 64.1%. When a cut-off value of 5.0 ng/mL was chosen for carcinoembryonic antigen (CEA) in these same serum samples, the values for sensitivity and specificity were 40.9% and 86.6%, respectively. Combined detection using survivin autoantibodies and CEA produced better sensitivity (51.3%) and specificity (89.9%) compared to the sensitivity of CEA (40.9%) and the specificities of the individual markers (64.1% and 86.6%, respectively). The area under a receiver operating characteristic curve was 0.617 for survivin autoantibodies, 0.630 for CEA and 0.694 for both markers together.

CONCLUSIONS

A positive association between autoantibodies against survivin and preoperative CEA concentrations in sera of patients with CRCs was established. Our results suggest that analysis of both parameters would assist in screening patients with CRC.

Synuclein gamma predicts poor clinical outcome in colon cancer with normal levels of carcinoembryonic antigen

Background

Synuclein gamma (SNCG), initially identified as a breast cancer specific gene, is aberrantly expressed in many different malignant tumors but rarely expressed in matched nonneoplastic adjacent tissues. In this study, we investigated the prognostic potential of SNCG in colon cancer particularly in the patients with normal carcinoembryonic antigen (CEA) levels.

Methods

SNCG levels were assessed immunohistochemically in cancer tissues from 229 colon adenocarcinoma patients with a mean follow-up of 44 months. Correlations between SNCG levels and clinicopathologic features, preoperative serum CEA level, and clinical outcome were analyzed statistically using SPSS.

Results

SNCG levels in colon adenocarcinoma were closely associated with intravascular embolus and tumor recurrence but independent of preoperative serum CEA levels. SNCG expression was an independent prognostic factor of a shorter disease-free survival (DFS) and overall survival (OS) (P < 0.0001). Multivariate analysis revealed that both tissue SNCG and serum CEA were independent prognostic factors of DFS (P = 0.001, <0.0001, respectively) for 170 patients with colon adenocarcinomas. Importantly, SNCG remained a prognostic determinant of DFS and OS (P = 0.001, 0.002) for 97 patients with normal preoperative serum CEA level.

Conclusions

Our results suggest for the first time that SNCG is a new independent predicator for poor prognosis in patients with colon adenocarcinoma, including those with normal CEA levels. Combination of CEA with SNCG improves prognostic evaluation for patients with colon adenocarcinoma.

Proteomic analysis of colorectal cancer: prefractionation strategies using two-dimensional free-flow electrophoresis

This review deals with the application of a new prefractionation tool, free-flow electrophoresis (FFE), for proteomic analysis of colorectal cancer (CRC). CRC is a leading cause of cancer death in the Western world. Early detection is the single most important factor influencing outcome of CRC patients. If identified while the disease is still localized, CRC is treatable. To improve outcomes for CRC patients there is a pressing need to identify biomarkers for early detection (diagnostic markers), prognosis (prognostic indicators), tumour responses (predictive markers) and disease recurrence (monitoring markers). Despite recent advances in the use of genomic analysis for risk assessment, in the area of biomarker identification genomic methods alone have yet to produce reliable candidate markers for CRC. For this reason, attention is being directed towards proteomics as a complementary analytical tool for biomarker identification. Here we describe a proteomics separation tool, which uses a combination of continuous FFE, a liquid-based isoelectric focusing technique, in the first dimension, followed by rapid reversed-phase HPLC (1–6 min/analysis) in the second dimension. We have optimized imaging software to present the FFE/RP-HPLC data in a virtual 2D gel-like format. The advantage of this liquid based fractionation system over traditional gel-based fractionation systems is the ability to fractionate large quantity protein samples. Unlike 2D gels, the method is applicable to both high-M_r proteins and small peptides, which are difficult to separate, and in the case of peptides, are not retained in standard 2D gels.

Quantitative expression analysis and prognostic significance of L-DOPA decarboxylase in colorectal adenocarcinoma

BACKGROUND

L-DOPA decarboxylase (DDC) is an enzyme that catalyses, mainly, the decarboxylation of L-DOPA to dopamine and was found to be involved in many malignancies. The aim of this study was to investigate the mRNA expression levels of the DDC gene and to evaluate its clinical utility in tissues with colorectal adenocarcinoma.

METHODS

Total RNA was isolated from colorectal adenocarcinoma tissues of 95 patients. After having tested RNA quality, we prepared cDNA by reverse transcription. Highly sensitive quantitative real-time PCR method for DDC mRNA quantification was developed using the SYBR Green chemistry. GAPDH served as a housekeeping gene. Relative quantification analysis was performed using the comparative C(T) method (2(-DeltaDeltaC(T))).

RESULTS

DDC mRNA expression varied remarkably among colorectal tumours examined in this study. High DDC mRNA expression levels were found in well-differentiated and Dukes' stage A and B tumours. Kaplan-Meier survival curves showed that patients with DDC-positive tumours have significantly longer disease-free survival (P=0.009) and overall survival (P=0.027). In Cox regression analysis of the entire cohort of patients, negative DDC proved to be a significant predictor of reduced disease-free (P=0.021) and overall survival (P=0.047).

CONCLUSIONS

The results of the study suggest that DDC mRNA expression may be regarded as a novel potential tissue biomarker in colorectal adenocarcinoma.

Cytokeratin 20 and vascular endothelial growth factor as molecular markers in Egyptian patients with colorectal cancer

PURPOSE

To investigate the expression of cytokeratin 20 (CK20) and vascular endothelial growth factor (VEGF) in the peripheral blood of colorectal cancer (CRC) patients, and correlate the findings with the pathologic data of the patients.

METHODS

This study was carried out on 50 subjects, 40 patients with histologically confirmed colorectal carcinoma undergoing elective surgery and 10 healthy individuals matched for age and sex. Total RNA extraction followed by real time quantitative RT-PCR and real time TaqMan quantitative assay for peripheral blood expression of CK20 and VEGF was done for both patients and controls.

RESULTS

(1) Statistically significant high levels of CK20,VEGF, CEA (p = 0.000 each) and CA19-9 (p = 0.002) in CRC patients when compared with controls; (2) Statistically significant increase in the expression of CK20 in advancing CRC stage C (p = 0.001) and with LN metastasis (p = 0.000); (3) Statistically significant increase in the expression of VEGF in advancing CRC stage C (p = 0.002), pathologic grade (p = 0.038), and with LN metastasis (p = 0.004); and (4) statistically positive correlation between CK20 and VEGF expressions, and also between these markers and CEA level.

CONCLUSION

CK20 and VEGF expressions in peripheral blood of CRC patients are promising molecular markers for CRC progression and metastasis.

A comparative study of protein expression in primary colorectal cancer and synchronous hepatic metastases: the significance of matrix metalloproteinase-1 expression as a predictor of liver metastasis

OBJECTIVE

This study was undertaken to determine the ability of protein expression in primary colorectal cancer and metastatic liver tumour tissues to predict hepatic metastasis and intrahepatic recurrence.

MATERIAL AND METHODS

Sixty patients with colorectal cancer were enrolled in this study. The expression of the following five proteins was assessed by immunohistochemical (IHC) staining: carcinoembryonic antigen (CEA); vascular endothelial growth factor (VEGF); matrix metalloproteinase (MMP)-1; MMP-7; and tissue inhibitor of metalloproteinases (TIMP)-1. Protein expression was measured in patients with primary colorectal cancer without liver metastasis (Group A), in patients with primary colorectal cancer with liver metastasis (primary tumour; Group B), and in patients with resected metastatic liver tumour tissues (liver metastasis; Group C).

RESULTS

IHC staining revealed more protease activity (MMP-1 and -7) in Group B than in Group A. Angiogenic activity (positive VEGF expression) was significantly greater in Group C than in Group B. Multivariate analysis showed that positive MMP-1 expression, the presence of lymphovascular invasion, and an elevated pre-operative serum CEA level (> 5 ng/ml) were significantly related to synchronous liver metastasis. However, intrahepatic recurrence was not related to protein expression, the presence of lymphovascular invasion, or the pre-operative CEA level.

CONCLUSIONS

Our findings suggest that protease activity is important for metastasis, and that angiogenic activity is essential for metastatic tumour growth. Furthermore, positive MMP-1 expression in primary colorectal tumour tissues was a significant predictor of liver metastasis. However, the prognostic impact of protein marker expression in terms of intrahepatic recurrence appears to be minimal.

Clinical significance of CEA and CA19-9 in postoperative follow-up of colorectal cancer

BACKGROUND

We evaluated the efficiency of CEA and CA19-9 as tools for diagnosing recurrence in the postoperative surveillance of colorectal cancer.

MATERIALS AND METHODS

A total of 227 patients who underwent curative resection for colorectal cancer between 1999 and 2003 at our hospital received complete follow-up according to the schedule determined prospectively. Using receiver operating characteristic (ROC) analysis, performance of postoperative values of CEA or CA19-9 for detecting recurrence was assessed.

RESULTS

The sensitivity (1.000) and specificity (0.978) of the postoperative values of CEA in the high preoperative CEA group were very high. Even in the normal preoperative CEA group, the area under the curve (AUC) of the ROC curve of CEA (0.740, 95% confidence interval [95% CI], 0.628-0.852) was significantly larger than 0.5 (P < 0.001). The postoperative values of CA19-9 showed high sensitivity (0.833) and specificity (0.900) in the high preoperative CA19-9 group, while the AUC of the ROC curve of the normal preoperative group was as small as 0.510 (95% CI, 0.376-0.644). In the high preoperative CA19-9 group, however, there was no significant difference between the AUC of CA19-9 (0.904, 95% CI, 0.786-1.000) and that of CEA (0.869, 95% CI, 0.744-0.994) (P = 0.334).

CONCLUSIONS

The measurement of CEA is an efficient way to detect recurrence. The efficiency of measuring CA19-9 for the purpose of detecting recurrence is low, especially in patients with a normal level of preoperative CA19-9. Even in patients with a high preoperative level of CA19-9, CEA might be able to fill the role of CA19-9.

Serum biomarkers of cell death for monitoring therapy response of gastrointestinal carcinomas

PURPOSE

Antitumour treatments are thought to exert their therapeutic efficacy mainly by induction of apoptosis in tumour cells. In epithelial cells, caspases, the key enzymes of apoptosis, cleave the intermediate filament protein cytokeratin (CK)-18 into specific fragments that are released into circulating blood and can be detected by a specific ELISA.

EXPERIMENTAL DESIGN

To investigate the use of CK-18 fragments as a potential biomarker for the treatment response, we examined the association of serum CK-18 levels and clinical response in 35 patients with gastrointestinal cancers.

RESULTS

While both cleaved and total CK-18 levels were intrinsically elevated in tumour patients, they were further increased during 5-fluorouracil (5-FU)-based therapy. Importantly, the increased levels of CK-18 could discriminate between patients with different clinical response. Cancer patients with a partial response or stable disease revealed a significantly higher increase of cleaved CK-18 during chemotherapy as compared to patients with progressive disease.

CONCLUSIONS

Our results suggest that detection of circulating caspase-cleaved CK-18 might be a useful serum biomarker for monitoring treatment response and should merit further evaluation in larger patient groups.

KRAS mutation and microsatellite instability: two genetic markers of early tumor development that influence the prognosis of colorectal cancer

INTRODUCTION

We examined two genetic markers established early in colorectal tumor development, microsatellite instability (MSI) and mutation of the KRAS proto-oncogene, to see if these genetic changes influence metastatic disease progression and survival.

PATIENTS AND METHODS

MSI and KRAS mutation status were assessed in 532 primary adenocarcinomas (stage I-IV) from patients treated by colon resection. Median follow-up was 4.1 years (range 0-13.3 years) overall, 5.4 years for survivors.

RESULTS

MSI and KRAS mutation were detected in 12 and 36% of cases, respectively. MSI was more common in early-stage disease (I, 15%; II, 21%; III, 10%; IV, 2%; P = 0.0001). Prevalence of KRAS mutation did not vary with stage (I, 36%; II, 34%; III, 35%; IV, 40%; P = ns). Disease-specific survival was far superior for MSI tumors than for microsatellite stability (MSS) tumors (5-year survival 92 vs. 59%, P < 0.0001). KRAS mutation was a marker of poor survival (5-year survival 55 vs. 68%, P = 0.0002). Using Cox regression analysis MSI, KRAS mutation, and stage were strong independent predictors of survival in the entire patient population. A high-mortality group with MSS/KRAS-mutant tumors was identified within the stage I and II cohort.

CONCLUSIONS

MSI and KRAS mutation provide fundamental genetic signatures influencing tumor behavior across patient subsets and stages of tumor development.

Limitations in SELDI-TOF MS whole serum proteomic profiling with IMAC surface to specifically detect colorectal cancer

BACKGROUND

Surface enhanced laser desorption and ionization time-of-flight mass spectrometry (SELDI-TOF-MS) analysis on serum samples was reported to be able to detect colorectal cancer (CRC) from normal or control patients. We carried out a validation study of a SELDI-TOF MS approach with IMAC surface sample processing to identify CRC.

METHODS

A retrospective cohort of 338 serum samples including 154 CRCs, 67 control cancers and 117 non-cancerous conditions was profiled using SELDI-TOF-MS.

RESULTS

No CRC "specific" classifier was found. However, a classifier consisting of two protein peaks separates cancer from non-cancerous conditions with high accuracy.

CONCLUSION

In this study, the SELDI-TOF-MS-based protein expression profiling approach did not perform to identify CRC. However, this technique is promising in distinguishing patients with cancer from a non-cancerous population; it may be useful for monitoring recurrence of CRC after treatment.

Serum carcinoembryonic antigen monitoring after curative resection for colorectal cancer: clinical significance of the preoperative level

AIM

We evaluated preoperative serum carcinoembryonic antigen (CEA) as a prognostic factor for colorectal cancer and determined when surveillance of this marker was useful.

METHODS

Serum CEA was measured preoperatively in 1,263 patients who underwent curative resection for colorectal cancer at 3-month intervals for the first 2 postoperative years and at 6-month intervals thereafter. Mean follow-up was 48 months (range 1-156 months).

RESULTS

The 5-year disease-free survival was less in patients with a high preoperative serum CEA level (P<0.0001). Among patients with a tumor recurrence, 38.5% had high follow-up serum CEA levels. The number of patients with high postoperative serum CEA levels exceeded the number of patients with high preoperative levels. High preoperative and follow-up serum CEA levels were independent prognostic factors for tumor recurrence (P=0.003 and P<0.001, respectively). In patients with high preoperative serum CEA levels, CEA surveillance had a 92.3% positive predictive value (PPV) and a 96.1% negative predictive value (NPV). The mean interval between postoperative serum CEA elevation and the diagnosis of a tumor recurrence [diagnostic interval (DI)] was 2.5 months (range 5-17 months). The DI was 0 in 18.8% of patients with a tumor recurrence.

CONCLUSION

High serum CEA levels preoperatively and at follow-up are prognostic factors for colorectal cancer. Postoperative serum CEA surveillance is used most effectively when patients have high preoperative serum CEA levels. Considering the DI of 0 in 18.8% of the patients, the current CEA surveillance schedule might be changed.

Molecular determinants of outcomes: linking tissue banks to outcomes databases

In the past, most outcomes research has focused on defining the clinicopathological determinants of outcomes. More recently, it has become apparent that the molecular features of tumor (as well as the genetic makeup of the patient) significantly influence outcomes, including responsiveness to therapy and prognosis. In view of this, there is a need for more research on the molecular determinants of outcomes. Research biorepositories are important vehicles for this type of research and they could potentially accelerate this work. For biomarker research to affect patient care, it is critical to effectively link patient outcomes data with descriptions of the molecular features of tumors. Effective linkage of outcomes data with tissue banks will dramatically accelerate biomarker research.

The use of kallikrein-related peptidases as adjuvant prognostic markers in colorectal cancer

Several members of the human tissue kallikrein-related peptidase (KLK) family are emerging cancer biomarkers. The aim of this study was to analyse the expression of a panel of KLKs in colorectal cancer and to find out if the multiparametric combination of them can increase the accuracy of prediction of patients survival beyond the traditional clinical information. Nine KLKs (KLK5-8, KLK10, KLK11, KLK13-15) were measured using ELISA assays in cytosolic extracts of 122 colon cancer tissues and their nearby normal mucosa, obtained during surgery. The mean levels of almost all KLKs in tumour tissues were significantly different from their counterparts of normal tissue (P<0.0001). KLK 5, 6, 7, 13, 14 were significantly associated with overall survival in univariate analysis, but after adjusting for age, TNM and differentiation stage, only KLK5 (HR: 1.24 (95% CI: 1.05-1.47)), KLK7 (HR: 1.57 (95% CI: 1.04-2.37)) and KLK14 (HR: 1.43 (95% CI: 1.05-1.94)) remained significant. Addition of a panel of selected KLK markers to clinical parameters gave an increment in AUC of 0.86 beyond the clinical factors at year 1, showing that it can increase the accuracy of prediction of overall survival beyond the traditional clinical information, particularly the short-term (1 year) survival after surgery.

Prognostic value of carcinoembryonic antigen distribution in tumor tissue of colorectal carcinoma

CONTEXT: Carcinoembryonic antigen (CEA) can be detected in colorectal tumor tissue but its role in the survival of patients remains controversial. OBJECTIVE: To characterize the expression of tissue CEA using immunohistochemical staining in colorectal tumors and to analyze the relationship between this finding and preoperative plasmatic level of CEA, morphologic features and survival of patients operated with curative intent for colorectal carcinoma. METHOD: Forty-seven patients were included in the study: 18 (38.3%) males and 29 (61.7%) females, with a mean age of 67.8 ± 9.7 years (37 to 84 years). Immediately before laparotomy, pre-operative serum levels of CEA were obtained where normal levels were considered <2.5 ng/mL for non-smokers, and <5.0 ng/mL for smokers. CEA immunohistochemical studies were carried out using anti-human CEA monoclonal mouse antibody. The expression of immunostaining for each neoplasia was classified according to the pattern of CEA tissular distribution into apical or cytoplasmic. The variables considered for the statistical analysis were plasmatic preoperative CEA level, location of the lesion within the large intestine, lesion diameter, lymph node involvement, Duke's classification, vein invasion, grade of cellular differentiation, survival and pattern of CEA tissular distribution. The statistical models utilized were Spearman's correlation and the Mann-Whitney, Kruskal-Wallis and Student t tests. Patients' survival was analyzed using the Kaplan-Meier method. RESULTS: The mean preoperative CEA value was 15.4 ± 5.5 ng/mL (0.2 to 92.1 ng/mL). The neoplasm was located in the colon in 29 (61.7%) and in the rectum in 18 (38.3%) patients. Eight (17.0%) patients were classified as Duke's stage A, 22 (46.8%) as stage B and 17 (36.2%) as stage C. On immunohistochemical studies, the pattern of CEA tissular distribution was apical in 33 (70.2%) patients and cytoplasmic in 14 (29.8%) patients. Patients with apical patterns presented a mean sera CEA level of 15.5 ± 6.5 ng/mL while those with cytoplasmic pattern attained a mean sera CEA level of 15.1 ± 7.3 ng/mL, with no significant difference between these values (P = 0.35). Apical distribution of CEA occurred in 6 (12.8%) Duke A, 18 (38.2%) Duke B and 9 (12.2%) Duke C patients, while cytoplasmic CEA tissular distribution was observed in 2 (4.2%) Duke A, 3 (6.4%) Duke B and 9 (19.1%) Duke C patients. Patients with Duke B neoplasms presented significantly more apical CEA tissular distribution patterns (P = 0.049) than subjects with cytoplasmic CEA tissular patterns. The apical CEA tissular distribution pattern in neoplasms was significantly more frequent in neoplasms with no lymph node compromise compared to the cytoplasmic pattern (P = 0.50). However, no significant differences were seen between apical and cytoplasmic CEA tissular distribution patterns in terms of colon or rectal site (P = 0.21), lesion diameter across greatest axis (P = 0.19), vein invasion (P = 0.13) or degree of cellular differentiation (P = 0.19). Of the 47 patients operated, 33 (70.2%) survived for more than 5 years where mean survival was 31.1 ± 5.6 months. Survival between patients with apical and cytoplasmic CEA tissular distribution showed no significant difference (P = 0.38). CONCLUSIONS: Although the apical distribution pattern of CEA was significantly more frequent in more advanced stages of Duke's classification, the CEA tissular distribution presented no relationship with serum CEA levels, morphological features of the neoplasm or survival of patients undergoing curative colorectal carcinoma resection.

Noninvasive molecular biomarkers for the detection of colorectal cancer

Colorectal cancer (CRC) is the third most common malignancy in the world. Because CRC develops slowly from removable precancerous lesions, detection of the disease at an early stage during regular health examinations can reduce both the incidence and mortality of the disease. Although sigmoidoscopy offers significant improvements in the detection rate of CRC, its diagnostic value is limited by its high costs and inconvenience. Therefore, there is a compelling need for the identification of noninvasive biomarkers that can enable earlier detection of CRC. Accordingly, many validation studies have been conducted to evaluate genetic, epigenetic or protein markers that can be detected in the stool or in serum. Currently, the fecal-occult blood test is the most widely used method of screening for CRC. However, advances in genomics and proteomics combined with developments in other relevant fields will lead to the discovery of novel non invasive biomarkers whose usefulness will be tested in larger validation studies. Here, noninvasive molecular biomarkers that are currently used in clinical settings and have the potential for use as CRC biomarkers are discussed.

Identification of colorectal cancer patients by serum protein profile using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry

AIM: To establish a serum protein fingerprinting technique coupled with a pattern-matching algorithm to distinguish colorectal cancer from healthy individuals.

METHODS: Serum samples were applied to metal affinity protein chips to generate mass spectra by surface-enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF-MS). Protein peak identification and clustering were performed using the Biomarker Wizard software. Proteomic spectra of serum samples from 84 colorectal cancer patients and age- and sex-matched 83 healthy individuals were used as a training set and a classification tree with 1 distinct protein masses was generated by using Biomarker Pattern software. The validity of the classification tree was then challenged with a blind test set including another 85 colorectal cancer patients and 83 healthy individuals. We additionally determined carcinoembryonic antigen (CEA) in all the serum samples included in the blind test set using an electrochemiluminescent immunoassay.

RESULTS: The software identified an average of 59 mass peaks/spectrum and 1 of the identified peaks at 5765 was used to construct the classification tree. The classification tree separated effectively colorectal cancer from healthy individuals, with a sensitivity of 98.81% and a specificity of 100.00%. The blind test challenged the model with a sensitivity of 97.65% and a specificity of 98.80%, and a positive predictive value of 98.81%, respectively. The specificity and sensitivity provided by CEA were significantly lower than that of the SELDI marker pattern (P < 0.05).

CONCLUSION: SELDI-TOF-MS technique can correctly distinguish colorectal cancer patients from healthy individuals and shows great potential for the development of a screening test for the detection of colorectal cancer.

The PRMT1 gene expression pattern in colon cancer

The methylation of arginine has been implicated in many cellular processes, such as regulation of transcription, mRNA splicing, RNA metabolism and transport. The enzymes responsible for this modification are the protein arginine methyltransferases. The most abundant methyltransferase in human cells is protein arginine methyltransferase 1. Methylation processes appear to interfere in the emergence of several diseases, including cancer. During our study, we examined the expression pattern of protein arginine methyltransferase 1 gene in colon cancer patients. The emerging results showed that the expression of one of the gene variants is associated with statistical significant probability to clinical and histological parameters, such as nodal status and stage. This is a first attempt to acquire an insight on the possible relation of the expression pattern of protein arginine methyltransferase 1 and colon cancer progression.

Persistent high postoperative carcinoembryonic antigen in colorectal cancer patients--is it important?

INTRODUCTION

Evaluation of pre- and postoperative serum CEA levels together has seldom been assessed for the prognosis of colorectal cancer (CRC).

OBJECTIVE

To concurrently evaluate pre- and postoperative CEA as factors of relapse and survival.

METHODS

The study consisted of 114 patients who had undergone surgery from February 2002 to June 2006 for CRC. All patients were classified into four groups according to their pre- and postoperative CEA levels. Data obtained for clinicopathologic parameters, lymph node metastasis, stage, recurrence, and CEA levels were analyzed to determine their association with survival. Multivariate analysis by the Cox proportional hazard regression model was performed to identify the independent prognostic factors associated with survival.

RESULTS

Postoperative serum CEA levels remained high in Group 3 (n = 32). Nineteen patients (59.3%) demonstrated a detectable cause for persistent high CEA levels, while the reasons for those in the other thirteen patients (40.6%) remained obscure. Abnormal preoperative CEA levels significantly correlated with the depth of tumor invasion, lymph node metastasis, TNM stage, and recurrence (p < 0.05). Abnormal postoperative CEA levels were significantly related to the depth of tumor invasion, TNM stage, and postoperative relapse (p<0.05). Patients in Group 3 demonstrated the worst survival rate. Abnormal postoperative CEA levels, lymph node metastasis, and location of the tumor were independent prognostic factors for survival.

CONCLUSION

The survival of patients with high postoperative CEA levels due to unknown reasons may be extended if they are exhaustively tested with sensitive diagnostic methods and treated at an early stage.

National Academy of Clinical Biochemistry Laboratory Medicine Practice Guidelines for Use of Tumor Markers in Testicular, Prostate, Colorectal, Breast, and Ovarian Cancers

Background: Updated National Academy of Clinical Biochemistry (NACB) Laboratory Medicine Practice Guidelines for the use of tumor markers in the clinic have been developed.

Methods: Published reports relevant to use of tumor markers for 5 cancer sites—testicular, prostate, colorectal, breast, and ovarian—were critically reviewed.

Results: For testicular cancer, α-fetoprotein, human chorionic gonadotropin, and lactate dehydrogenase are recommended for diagnosis/case finding, staging, prognosis determination, recurrence detection, and therapy monitoring. α-Fetoprotein is also recommended for differential diagnosis of nonseminomatous and seminomatous germ cell tumors. Prostate-specific antigen (PSA) is not recommended for prostate cancer screening, but may be used for detecting disease recurrence and monitoring therapy. Free PSA measurement data are useful for distinguishing malignant from benign prostatic disease when total PSA is &lt;10 μg/L. In colorectal cancer, carcinoembryonic antigen is recommended (with some caveats) for prognosis determination, postoperative surveillance, and therapy monitoring in advanced disease. Fecal occult blood testing may be used for screening asymptomatic adults 50 years or older. For breast cancer, estrogen and progesterone receptors are mandatory for predicting response to hormone therapy, human epidermal growth factor receptor-2 measurement is mandatory for predicting response to trastuzumab, and urokinase plasminogen activator/plasminogen activator inhibitor 1 may be used for determining prognosis in lymph node–negative patients. CA15-3/BR27–29 or carcinoembryonic antigen may be used for therapy monitoring in advanced disease. CA125 is recommended (with transvaginal ultrasound) for early detection of ovarian cancer in women at high risk for this disease. CA125 is also recommended for differential diagnosis of suspicious pelvic masses in postmenopausal women, as well as for detection of recurrence, monitoring of therapy, and determination of prognosis in women with ovarian cancer.

Conclusions: Implementation of these recommendations should encourage optimal use of tumor markers.

Electrochemical immunoassay of carcinoembryonic antigen based on a lead sulfide nanoparticle label

We describe a lead sulfide nanoparticle (PbS NP)-based electrochemical immunoassay to detect a tumor biomarker, carcinoembryonic antigen (CEA). Cubic PbS NPs were prepared and functionalized with thioglycolic acid (TGA), which stabilized the formed NPs and offered carboxyl groups to conjugate with CEA antibodies. PbS NP conjugated with monoclonal CEA antibody was used as a label in an immunorecognition event. After a complete sandwich immunoreaction among the primary CEA antibody (immobilized on the carboxyl-modified magnetic beads), CEA and the PbS-labeled secondary antibody (PbS-anti-CEA), PbS labels were captured to the magnetic-bead (MB) surface through the antibody-antigen immunocomplex. Electrochemical stripping analysis of the captured PbS was used to quantify the concentration of CEA after an acid-dissolution step. The MBs and the magnetic separation platform were used to integrate a facile antibody immobilization with immunoreactions and the isolation of immunocomplexes from reaction solutions in the immunoassay. The voltammetric response is highly linear over the range of 1-50 ng ml(-1) CEA, and the limit of detection is estimated to be 0.5 ng ml(-1). The performance of this nanoparticle-based electrochemical immunoassay was successfully evaluated with human serum spiked with CEA, indicating that this convenient and sensitive technique offers great promise for rapid, simple and cost-effective analysis of tumor biomarkers in biological fluids.

Disposable electrochemical immunosensor for carcinoembryonic antigen using ferrocene liposomes and MWCNT screen-printed electrode

Disposable electrochemical immunosensor for the detection of carcinoembryonic antigen (CEA) in saliva and serum was developed. Monoclonal anti-CEA antibodies (alphaCEA) were covalently immobilized on polyethyleneimine wrapped multiwalled carbon nanotubes screen-printed electrode. A sandwich immunoassay was performed with CEA and alphaCEA tagged ferrocene carboxylic acid encapsulated liposomes (alphaCEA-FCL). The square wave voltammetry (SWV) was employed to analyze faradic redox responses of the released ferrocene carboxylic acid from the immunoconjugated liposomes on the electrode surface. The magnitude of the SWV peak current was directly related to the concentration of CEA. The calibration curve for CEA concentration was in the range of 5 x 10(-12) to 5 x 10(-7)gmL(-1) with a detection limit of 1 x 10(-12)gmL(-1) (S/N=3). This method provides a high precise and sensitive determination of CEA in human blood serum and saliva samples.

Biology and potential clinical implications of tissue inhibitor of metalloproteinases-1 in colorectal cancer treatment

Colorectal cancer (CRC) is the second leading cause of cancer-related death in the industrialized world. About half of "curatively" resected patients develop recurrent disease within the next 3-5 years despite the lack of clinical, histological and biochemical evidence of remaining overt disease after resection of the primary tumour. Availability of validated biological markers for early detection, selection for adjuvant therapy, prediction of treatment efficacy and monitoring of treatment efficacy would most probably increase survival. Tissue inhibitor of metalloproteinases-1 (TIMP-1) may be such a marker. TIMP-1 inhibits the proteolytic activity of metalloproteinases, which are centrally involved in tumour invasion and metastases. However, in clinical investigations high tumour tissue or plasma levels of TIMP-1 have shown a strong and independent association with a shorter survival time in CRC patients, suggesting that TIMP-1 could have a tumour-promoting function. Furthermore, measurement of plasma TIMP-1 has been shown to be useful for disease detection, with a high sensitivity and high specificity for early-stage colon cancer. This review describes some basic information on the current knowledge of the biology of TIMP-1 as well as the potential use of TIMP-1 as a biological marker in the management of CRC patients.

Proteomic expression analysis of surgical human colorectal cancer tissues: up-regulation of PSB7, PRDX1, and SRP9 and hypoxic adaptation in cancer

Colorectal adenocarcinoma is one of the worldwide leading causes of cancer deaths. Discovery of specific biomarkers for early detection of cancer progression and the identification of underlying pathogenetic mechanisms are important tasks. Global proteomic approaches have thus far been limited by the large dynamic range of molecule concentrations in tissues and the lack of selective enrichment of the low-abundance proteome. We studied paired cancerous and normal clinical tissue specimens from patients with colorectal adenocarcinomas by heparin affinity fractionation enrichment (HAFE) followed by 2-D PAGE and tandem mass spectrometric (MS/MS) identification. Fifty-six proteins were found to be differentially expressed, of which 32 low-abundance proteins were only detectable after heparin affinity enrichment. MS/MS was used to identify 5 selected differentially expressed proteins as proteasome subunit beta type 7 (PSB7), hemoglobin alpha subunit (HBA), peroxiredoxin-1 (PRDX1), argininosuccinate synthase (ASSY), and signal recognition particle 9 kDa protein (SRP9). This is the first proteomic study detecting the differential expression of these proteins in human colorectal cancer tissue. Several of the proteins are functionally related to tissue hypoxia and hypoxic adaptation. The relative specificities of PSB7, PRDX1, and SRP9 overexpression in colon cancer were investigated by Western blot analysis of patients with colon adenocarcinomas and comparison with a control cohort of patients with lung adenocarcinomas. Furthermore, immunohistochemistry on tissue sections was used to define the specific locations of PSB7, PRDX1, and SRP9 up-regulation within heterogeneous primary human tumor tissue. Overexpression of the three proteins was restricted to the neoplastic cancer cell population within the tumors, demonstrating both cytoplasmic and nuclear localization of PSB7 and predominantly cytoplasmic localization of PRDX1 and SRP9. In summary, we describe heparin affinity fractionation enrichment (HAFE) as a prefractionation tool for the study of the human primary tissue proteome and the discovery of PSB7, PRDX1, and SRP9 up-regulation as candidate biomarkers of colon cancer.