The Use of Serologic Tumor Markers in Gastrointestinal Malignancies

Preoperative CEA and TAG-72 Serum Levels as Prognostic Indicators in Resectable Gastric Carcinoma

We evaluated in 74 patients with resectable primary gastric carcinoma, the prognostic value of the preoperative circulating serum levels of CEA and TAG-72. Serum levels of CEA were above the cutoff level of 6 ng/ml in 18.9% of patients; TAG-72 levels were higher than 6 U/ml in 31% of patients. Pretreatment mean CEA levels were significantly lower (p<0.01) in patients with stage I tumors (2.9 ± 0.3 ng/ml) than in those with more advanced tumors (stage II: 14.5 ± 6.8 ng/ml; stage HI-TV: 6.8 ± 1.5 ng/ml). Similarly, significant differences in mean TAG-72 serum levels were found between stage I (3.5 ± 1.8 U/ml) and stage II and stage III-IV (30.4 ± 20.7 U/ml and 26.1 ± 9.7 U/ml, respectively) (p<0.05). In addition, TAG-72 levels were also higher in poorly differentiated and moderately differentiated tumors (38.5 ± 20.1 U/ml and 23.1 ± 9.4 U/ml, respectively) than in well differentiated tumors (4.4 ± 0.9 U/ml) (p<0.05). The results further indicated that high preoperative serum levels of CEA predicted shorter relapse-free survival duration (p<0.01), and that high TAG-72 levels were associated with shorter relapse-free and overall survival (p < 0.0001 and p < 0.0005, respectively). In addition, separate Cox multivariate analysis showed that preoperative TAG-72 was, after stage, the strongest factor to predict both relapse-free and overall survival (p < 0.0001 and p < 0.005, respectively) in patients with gastric cancer.

The Value of CEA and CA 19-9 in Detecting Cancer in a Group of High-Risk Subjects with Gastrointestinal Symptoms

The aim of this study was to evaluate the clinical value of CEA and CA 19-9 in a potential high-risk population of subjects with gastrointestinal complaints. The basic question was whether the determination of these markers, in addition to some other clinical features in this high risk population, could be helpful in diagnosing intraabdominal cancer. Two hundred and two patients with gastrointestinal complaints underwent standard diagnostic procedures and were followed for at least one year. For every patient, CEA and CA 19-9 levels were obtained at the first examination; the evaluating physician was blinded to the marker levels. The determinants of the likelihood of cancer were evaluated by multivariate analysis. Seventeen patients were diagnosed as having intraabdominal cancers. With the presence of melena (RR=101.63, p=0.007), nonspecific gastrointestinal symptoms (RR=12.54, p=0.026), increasing age (RR=1.09, p=0.028) and abnormal CEA (RR=240.79, p=0.000), the risk of having cancer increased significantly and independently. The presence of a primary gastric complaint was associated with a lower risk of cancer in this cohort (RR=0.01, p=0.04). Markers were not used in the diagnostic workup. In conclusion, in patients presenting with gastrointestinal complaints, the finding of elevated CEA levels may help in the diagnosis of cancer by prompting a more extensive search for intraabdominal cancer.

Prognostic Significance of Carcinoembryonic Antigen Staining in Cancer Tissues of Gastric Cancer Patients

PURPOSE

The aim of this study was to assess the significance of the correlation among tissue carcinoembryonic antigen (CEA) expression with serum CEA (sCEA) levels and long-term survival to highlight the clinical prognostic significance of tissue CEA expression in gastric cancer patients.

METHODS

Immunohistological method and radioimmunoassay were used to assess tissue and sCEA expression, respectively. Univariate and multivariate analyses were performed to determine correlations, and the Kaplan-Meier method was used to investigate the prognostic significance.

RESULTS

Our results demonstrate that tissue CEA in gastric cancer is significantly correlated with preoperative sCEA levels (p = 0.031), depth of invasion (p = 0.001), lymph node metastasis (p < 0.001), distant metastasis (p = 0.001), and TNM staging (p < 0.001). The 5-year survival rates were 67.6, 53.9, and 40.1 % for negatively, moderately, and intensely positively stained tissues (p < 0.001), and 57.0 and 37.9 % for serum with normal and elevated CEA expression (p = 0.031). Multivariate analysis revealed that tissue CEA can be considered an independent prognostic factor. Further analysis illustrated that patients with negative expression in both tissue and serum had better prognosis compared with those positively expressing CEA in both tissue and serum and/or those positively expressing CEA in either tissue or serum (p < 0.001). Our results also demonstrated that patients with negative tissue CEA staining and elevated sCEA expression had a better 5-year survival.

CONCLUSION

Tissue CEA expression in gastric cancer is directly correlated with sCEA levels and long-term prognosis. Thus, tissue CEA expression can be considered as a useful biomarker to improve the interpretation of sCEA levels in predicting long-term survival.

Potential role of O-GlcNAcylation and involvement of PI3K/Akt1 pathway in the expression of oncogenic phenotypes of gastric cancer cells in vitro

O-GlcNAcylation is a monosaccharide modification by a residue of N-acetylglucosamine (GlcNAc) attached to serine or threonine moieties on nuclear and cytoplasmic proteins. O-GlcNAcylation is dynamically regulated by O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). Increasing evidence suggests that O-GlcNAcylation is involved in a variety of human cancers. However, the exact role of O-GlcNAcylation in tumor progression remains unclear. Here, we show that O-GlcNAcylation accelerates oncogenic phenotypes of gastric cancer. First, cell models with increased or decreased O-GlcNAcylation were constructed by OGT overexpression, downregulation of OGA activity with specific inhibitor Thiamet-G, or silence of OGT. MTT assays indicated that O-GlcNAcylation increased proliferation of gastric cancer cells. Soft agar assay and Transwell assays showed that O-GlcNAcylation significantly enhanced cellular colony formation, migration, and invasion in vitro. Akt1 activity was stimulated by upregulation of phosphorylation at Ser473 mediated by elevated O-GlcNAcylation. The enhanced cell invasion by Thiamet-G treatment was suppressed by PI3K inhibitor LY294002. Although the cell invasion induced by Thiamet-G was reduced by Akt1 shRNA, it was still higher in comparison with that to the control (cells with Akt1 shRNA alone). And Akt1 overexpression promoted Thiamet-G-induced cell invasion. These results suggested that O-GlcNAcylation enhanced oncogenic phenotypes possibly partially involving PI3K/Akt signaling pathway.

Association of serum levels of CEA, CA199, CA125, CYFRA21-1 and CA72-4 and disease characteristics in colorectal cancer

Identifying predictive biomarkers for colorectal cancer would facilitate diagnosis and treatment of the disease. This study aimed to investigate the association of the serological biomarkers CEA, CA19-9, CA125, CYFRA21-1 and CA72-4 with patient characteristics and disease outcomes in colorectal cancer. Patients (N = 373) with colorectal cancer were evaluated for the association of CEA, CA19-9, CA125, CYFRA21-1, and CA72-4 pre and post-surgery and at disease recurrence with demographics, disease characteristics including pathological types, degree of differentiation, invasion depth, abdominal lymph node metastasis, TMN stage, Dukes stage, location of cancer and metastasis, and disease outcomes. It was more common for a patient to express these markers prior to surgery and at disease recurrence than following surgery. Overall, the serum levels of CEA, CA19-9, CA125, CYFRA21-1, and CA72-4 were not associated with age, gender, pathological type and location of cancer (all P-values >0.05), but were associated with the poor tumor differentiation, higher tumor invasion, greater degree of abdominal lymph node metastasis, and higher TNM and Duke stage tumors (all P-values < 0.01). CEA expression was associated with older ages (median age 65 years). Multivariate analysis indicated that CEA was correlated with overall survival and none of the markers correlated with disease recurrence. The expression of CEA, CA19-9, CA125, CYFRA21-1, and CA72-4 was associated with specific disease characteristics which tended to indicated more advanced disease and disease recurrence consistent with these biomarkers being useful for detecting colorectal cancer.

Detection of perioperative cancer antigen 72-4 in gastric juice pre- and post-distal gastrectomy and its significances

Gastric carcinoma is one of the most common malignancies nowadays, and caner antigen 72-4 (CA 72-4) in gastric juice has been rarely studied. To compare CA 72-4 in gastric juice pre- and post-distal gastrectomy (DG) and analyze its possible significances, we selected 64 patients diagnosed with gastric carcinoma who underwent DG and collected their perioperative gastric juice samples whose contents of CA 72-4 were detected. We found that CA 72-4 in gastric juice pre-gastrectomy is significantly higher among patients in advanced stages and correlated with tumor TNM classification (P < 0.01), within which tumor size, levels of gastric wall invaded, and number of metastatic lymph nodes are significant influencing factors (P < 0.05); CA 72-4 in gastric juice post-gastrectomy is significantly higher than that pre-surgery (P < 0.01), and it is significantly correlated with tumor TNM classification and radical degree (P < 0.01), and regards the sum of distances from tumor to two cutting edges and the classification of cutting edge as significant impact factors (P < 0.05); nine patients whose CA 72-4 in gastric juice rose post-DG show features indicating poor prognosis; the difference of CA 72-4 in gastric juice between pre- and post-gastrectomy is significantly correlated with tumor TNM classification and radical degree (P < 0.05), and regards tumor size, levels of gastric walls invaded, the sum of distances from tumor to two cutting edges and the classification of cutting edge as significant influential factors (P < 0.05). We conclude that CA 72-4 in gastric juice pre- and post-gastrectomy can provide us with much information about tumor and radical gastrectomy and that CA 72-4 in gastric juice post-gastrectomy and the difference of CA 72-4 in gastric juice between pre- and post-gastrectomy may indicate prognosis.

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.

Clinical utility of serum tumor markers in the diagnosis of malignant intestinal occlusion. A prospective observational study

AIM

The aim of the present observational study was to evaluate the diagnostic accuracy of CEA, CA 19-9 and CA 72-4 in patients with bowel obstruction.

METHODS

One-hundred three patients admitted to an emergency unit with clinical and radiological signs of intestinal occlusion of unknown origin were prospectively studied. Patients submitted to emergency surgery were excluded. All patients underwent standard diagnostic procedures and serological assay of tumor markers.

RESULTS

Colorectal cancer was diagnosed in 22 patients (21.4%), while 81 patients (78.6%) presented a benign condition. The sensitivity of CEA, CA 19-9 and CA 72-4 for colorectal cancer was 36.4%, 31.8% and 9.1%, respectively. Marker specificity was 91.4%, 90.1% and 95.1%, respectively. The combination of CEA and CA 19-9 increased the sensitivity to 45.5% but decreased the specificity to 83.9%. The overall accuracy was 79.6%, 77.7% and 76.7%, respectively. All positive cancer cases had advanced disease. All patients with CEA levels >10 ng/mL or CA 19-9 >100 U/mL had colorectal cancer.

CONCLUSIONS

Even in a highly selected population, tumor marker sensitivity was rather low and specificity incomplete. However, elevated levels may guide the diagnostic and therapeutic course in patients with obstructing colorectal cancer.

Sensitive and specific detection of early gastric cancer with DNA methylation analysis of gastric washes

BACKGROUND & AIMS

Aberrant DNA methylation is an early and frequent process in gastric carcinogenesis and could be useful for detection of gastric neoplasia. We hypothesized that methylation analysis of DNA recovered from gastric washes could be used to detect gastric cancer.

METHODS

We studied 51 candidate genes in 7 gastric cancer cell lines and 24 samples (training set) and identified 6 for further studies. We examined the methylation status of these genes in a test set consisting of 131 gastric neoplasias at various stages. Finally, we validated the 6 candidate genes in a different population of 40 primary gastric cancer samples and 113 nonneoplastic gastric mucosa samples.

RESULTS

Six genes (MINT25, RORA, GDNF, ADAM23, PRDM5, MLF1) showed frequent differential methylation between gastric cancer and normal mucosa in the training, test, and validation sets. GDNF and MINT25 were most sensitive molecular markers of early stage gastric cancer, whereas PRDM5 and MLF1 were markers of a field defect. There was a close correlation (r = 0.5-0.9, P = .03-.001) between methylation levels in tumor biopsy and gastric washes. MINT25 methylation had the best sensitivity (90%), specificity (96%), and area under the receiver operating characteristic curve (0.961) in terms of tumor detection in gastric washes.

CONCLUSIONS

These findings suggest MINT25 is a sensitive and specific marker for screening in gastric cancer. Additionally, we have developed a new method for gastric cancer detection by DNA methylation in gastric washes.

Recent advances in the molecular diagnosis and prognosis of colorectal cancer

Colon cancer remains a leading cause of mortality worldwide despite the well-characterized molecular events in the adenoma-to-carcinoma sequence. There has been a strong emphasis on early detection of colon cancer, and fecal DNA-based methods have been developed to assist with early screening. Tissue-based assays have been utilized for many years to assess tumor aggressiveness and to determine prognosis and response to chemotherapeutic interventions. The most widely used serum marker for colon cancer (carcinoembryonic antigen) remains a useful modality to assess for occult disease following curative resection. Identification of tumor mutations in circulating tumor cells and microarray analysis holds a great deal of promise in the diagnosis and prognosis of patients with colorectal cancer. The inhibitors of apoptosis may be important markers to determine resistance to radiation cytotoxicity in rectal cancer. This report presents a summary of the current status of the molecular markers of colorectal cancer to establish a diagnosis, determine prognosis and chemoradiotherapeutic interventions, and assess relapse following curative surgery.

Detection of survivin-expressing circulating cancer cells (CCCs) in peripheral blood of patients with gastric and colorectal cancer reveals high risks of relapse

BACKGROUND

We previously demonstrated that the detection of circulating cancer cells (CCCs) expressing survivin mRNA could provide valuable information for predicting metastasis and recurrence in breast cancer. The objective of this study was to investigate whether or not the detection of survivin expression in the peripheral blood could also have significant effects on the clinical outcomes of patients with gastric and colorectal cancer.

METHODS

Survivin-expressing CCCs in peripheral blood samples obtained from 55 gastric cancer patients, 86 colorectal cancer patients, and 87 healthy volunteers were quantitatively examined by using a RT-PCR ELISA. Its clinical significance was statistically evaluated.

RESULTS

The CCCs in the peripheral blood samples were detected in 45.4% and 44.0% of gastric and colorectal cancer patients, respectively. The presence of survivin-expressing CCCs was found to be significantly associated with the degree of tumor penetration, nodal status, and disease stages for both types of cancers. During a follow-up period of 36 months, patients who had a positive detection at the time of the initial assay test had a higher relapse rate than those who had a negative detection. As well, survivin-expressing CCCs were statistically shown to be a significant and independent predictor for cancer recurrence. The detection of survivin-expressing CCCs was also demonstrated to be more accurate in terms of predicting recurrence than traditional detection methods such as plasma carcinoembryonic antigen (CEA) measurements.

CONCLUSION

The detection of CCCs expressing survivin mRNA could be used to accurately identify gastric and colorectal cancer patients with high risks of relapse.

Identification of potential markers for the detection of pancreatic cancer through comparative serum protein expression profiling

OBJECTIVE

Early detection is the only promising approach to significantly improve the survival of patients with pancreatic cancer (PCa). Noninvasive tools for the diagnosis, prognosis, and monitoring of this disease are of urgent need. The purpose of this study was to identify and validate new biomarkers in PCa patient serum samples.

METHODS

Surface-enhanced laser desorption/ionization time-of-flight mass spectrometry has been applied to analyze serum protein alterations associated with PCa and to identify sets of potential biomarkers indicative for this disease. A cohort of 96 serum samples from patients undergoing PCa surgery was compared with sera from 96 healthy volunteers as controls. The sera were fractionated by anion exchange chromatography, and 3 of 6 fractions were analyzed onto 2 different chromatographic arrays.

RESULTS

Data analysis revealed 24 differentially expressed protein peaks (P < 0.001), of which 21 were downregulated in the PCa samples. The best single marker can predict 92% of the controls and 89% of the cancer samples correctly. In addition, multivariate pattern analysis was performed. The best pattern model using a set of 3 markers was obtained using fraction 6 on immobilized metal affinity capture, loaded with Cu-Cu arrays. With this pattern model, a sensitivity of 100% and a specificity of 98% for the training data set and a sensitivity of 83% and specificity of 77% for the test data set were achieved with the PCa group set as true positive. Several of protein peaks, including the best single marker at 17.27 kd and other proteins from the pattern models, were purified and identified by peptide mapping and postsource decay-matrix-assisted laser desorption ionization-time-of-flight mass spectrometry. Apolipoprotein A-II, transthyretin, and apolipoprotein A-I were identified as markers, and these identified proteins were decreased at least 2-fold in PCa serum when compared with the control group.

CONCLUSIONS

PCa is associated with a specific decrease of distinct serum proteins, which allows a reliable differentiation between pancreatic cancer and healthy controls.

Fibrinogen gamma overexpression in pancreatic cancer identified by large-scale proteomic analysis of serum samples

Detection of serum markers for pancreatic cancer has been elusive. Although CA 19-9 is most commonly used, its sensitivity and specificity are modest. We used large-scale proteomics to identify potential serum markers for pancreatic cancer. Samples were analyzed using high-resolution two-dimensional gel electrophoresis to identify differentially expressed proteins in 32 normal and 30 pancreatic cancer patients. Up to 1,744 protein spots were resolved for each serum sample. Candidate proteins were identified using mass spectrometry. ANOVA was used to identify proteins that could discriminate cancer from normal sera. Serum fibrinogen level was also measured using enzymatic assay. Immunohistochemistry was used to detect fibrinogen in resected pancreatic cancers. One hundred fifty-four proteins were commonly overexpressed in all pancreatic cancers. Nine protein spots (four with identifications by mass spectrometry) could effectively separate cancer from normal controls using cross-validation. These proteins successfully discriminated all pancreatic cancer samples (30 of 30) and 94% of normal (30 of 32) samples. Prominent among these candidates was fibrinogen gamma, which was subsequently confirmed to be overexpressed in pancreatic cancer sera by enzymatic analysis (54.1 +/- 64.1 versus 0.0 +/- 0.0 mg/dL, P < 0.05) and tissue by immunohistochemistry (67% versus 29%, P < 0.05) relative to normal pancreas. Proteomic analysis combining two-dimensional gel electrophoresis and mass spectrometry successfully identified 154 potential serum markers for pancreatic cancer. Of these, fibrinogen gamma, a protein associated with the hypercoagulable state of pancreatic cancer, discriminated cancer from normal sera. Fibrinogen is a potential tumor marker in pancreatic cancer.

Artificial neural networks analysis of surface-enhanced laser desorption/ionization mass spectra of serum protein pattern distinguishes colorectal cancer from healthy population

PURPOSE

The low specificity and sensitivity of the carcinoembryonic antigen test makes it not an ideal biomarker for the detection of colorectal cancer. We developed and evaluated a proteomic approach for the simultaneous detection and analysis of multiple proteins for distinguishing individuals with colorectal cancer from healthy individuals.

EXPERIMENTAL DESIGN

We subjected serum samples (including 55 colorectal cancer patients and 92 age- and sex-matched healthy individuals) from 147 individuals, for analysis by surface-enhanced laser desorption/ionization (SELDI) mass spectrometry. Peaks were detected with Ciphergen SELDI software version 3.0. Using a multilayer artificial neural network with a back propagation algorithm, we developed a classifier for separating the colorectal cancer groups from the healthy groups.

RESULTS

The artificial neural network classifier separated the colorectal cancer from the healthy samples, with a sensitivity of 91% and specificity of 93%. Four top-scored peaks, at m/z of 5,911, 8,930, 8,817, and 4,476, were finally selected as the potential "fingerprints" for detection of colorectal cancer.

CONCLUSIONS

The combination of SELDI-TOF mass spectrometry with the artificial neural networks in the analysis of serum protein yields significantly higher sensitivity and specificity values for the detection and diagnosis of colorectal cancer.

Gastric cancer

Gastric cancer is one of the most common cancers and one of the most frequent causes of cancer-related deaths. The incidence, diagnostic studies, and therapeutic options have undergone important changes in the last decades, but the prognosis for gastric cancer patients remains poor, especially in more advanced stages. Surgery is the mainstay of treatment of this disease, even if it is associated with a high rate of locoregional and distant recurrence. There is ongoing debate regarding the role of adjuvant treatment In advanced disease, palliation of symptoms, rather than cure, is the primary goal of patient management. Several combination therapies have been developed and have been examined in phase III trials; however, in most cases, they have failed to demonstrate a survival advantage over the reference arm. This review summarizes the most important recommendations for the management of patients with gastric cancer.

Diagnosis of pancreatic cancer using serum proteomic profiling

In the United States, mortality rates from pancreatic cancer (PCa) have not changed significantly over the past 50 years. This is due, in part, to the lack of early detection methods for this particularly aggressive form of cancer. The objective of this study was to use high-throughput protein profiling technology to identify biomarkers in the serum proteome for the early detection of resectable PCa. Using surface-enhanced laser desorption/ionization mass spectrometry, protein profiles were generated from sera of 49 PCa patients and 54 unaffected individuals after fractionation on an anion exchange resin. The samples were randomly divided into a training set (69 samples) and test set (34 samples), and two multivariate analysis procedures, classification and regression tree and logistic regression, were used to develop classification models from these spectral data that could distinguish PCa from control serum samples. In the test set, both models correctly classified all of the PCa patient serum samples (100% sensitivity). Using the decision tree algorithm, a specificity of 93.5% was obtained, whereas the logistic regression model produced a specificity of 100%. These results suggest that high-throughput proteomics profiling has the capacity to provide new biomarkers for the early detection and diagnosis of PCa.

Follow-up strategies after curative resection of colorectal cancer

Consensus is lacking as to the best strategy for following patients who have undergone definitive surgical medical treatment for colon cancer. The goal of any surveillance program should be detection of recurrent disease at a sufficiently early time to allow subsequent curative therapy. Although periodic clinical examinations, laboratory tests, radiographic imaging, and carcinoembryonic antigen (CEA) testing have been utilized as a form of surveillance, such aggressive and costly intervention has not been validated through clinical studies. Four of the five randomized trials comparing such an intensive surveillance strategy to less frequent testing have not demonstrated the intensive approach to lead to an improvement in overall survival. Furthermore, intensive testing is both costly and has been shown not to improve quality of life. Further research designing appropriate postoperative testing is needed to guide physicians and patients after the curative resection of a colorectal cancer.

A novel secreted tumor antigen with a glycosylphosphatidylinositol-anchored structure ubiquitously expressed in human cancers

In a search for novel genes expressed in human cancers, we identified one gene from an assembled expressed sequence tag database. Northern blot analysis revealed that the gene, termed alcan, was expressed in various types of human cancer cell lines and in the fetus, but not in normal tissues. The alcan gene is located on chromosome 6 and is encoded on a 246-amino-acid protein with weak homology to classical major histocompatibility complex class I. Its gene product, ALCAN, had hydrophobic amino acid clusters at both the N- and C-terminal regions and was predicted to be a glycosylphosphatidylinositol (GPI)-anchored membrane protein. Flow cytometric analysis revealed that ALCAN was detected on the surface of human cancer cells and on alcan-transfected CHO-K1 cells. ALCAN was also secreted from these cells, suggesting that some portion of the molecules was secreted by enzymatic cleavage by, for example, phospholipases. Mutational analysis of ALCAN suggested that the GPI-anchored position was the Ser(216) residue. These findings indicate that ALCAN may be a potential target for cancer diagnosis or therapy.

Bone marrow micrometastases and gastrointestinal cancer detection and significance

Accurate staging of cancer is important, as the presence or absence of systemic spread determines treatment. The sensitivity of current imaging and biochemical techniques is suboptimal for the detection of minimal residual disease and latent metastases. This results in understaging and potential undertreatment. To improve detection of disseminated epithelial malignancy, immunohistochemical and molecular methods have been employed that search for epithelial cell-specific proteins in nonepithelial tissue. Bone marrow is mesenchymal tissue (that does not normally express epithelial cell components) and represents an accessible window for detection of micrometastatic carcinoma cells. Detection methods for epithelial cell components (cytokeratins, epithelial membrane antigen, carcinoembryonic antigen) include immunohistochemistry, flow cytometry, reverse transcriptase polymerase chain reaction (rt-PCR), and enzyme linked immunoassay (ELISA). Micrometastatic cells in bone marrow are viable, capable of proliferation, resistant to immune attack, and insensitive to s-phase chemotherapeutic agents. Patients with carcinomas of the lung, breast, prostate, or gastrointestinal tract and in whom bone marrow micrometastases are detected have a foreshortened interval to recurrence and impaired survival. Detection of micrometastases deserves serious consideration in treatment protocols, and standardization of methods is now required.

AGA technical review on the epidemiology, diagnosis, and treatment of pancreatic ductal adenocarcinoma. American Gastroenterological Association

This literature review and the recommendations therein were prepared for the American Gastroenterological Association Clinical Practice and Practice Economics Committee. The paper was approved by the Committee in March 1999 and by the AGA Governing Board in May 1999.

Soluble member(s) of the mesothelin/megakaryocyte potentiating factor family are detectable in sera from patients with ovarian carcinoma

mAb OV569 was made by immunizing mice with ovarian carcinoma cells. It binds to cells from ovarian carcinomas and, to a lesser extent, to cells from certain other carcinomas whereas the binding to normal tissues is low to nondetectable. It also binds to soluble molecule(s) in culture supernatants from antigen-positive carcinomas. OV569 recognizes a protein(s) of 42-45 kDa with the same N-terminal amino acid sequence as the membrane-bound portion of mesothelin and megakaryocyte potentiating factor (MPF). Binding assays with fusion proteins comprising either the N-terminal part of mesothelin/MPF (D1Ig), reported to be easily cleaved off, or a noncleavable, membrane-associated part (D2Ig) showed that OV569 only binds to D2hIg. A new member of the mesothelin/MPF family was discovered, which has an 82-bp insert in the membrane-associated part, leading to a frameshift of 212 bp, and whose predicted molecular structure indicates that it is soluble. To test patient sera for soluble tumor antigen, antigen was isolated from cell-free tumor culture supernatants via immunoadsorption with OV569 and used to generate murine mAbs to an epitope different from the one to which OV569 binds, after which mAbs to two different epitopes were used to develop a "sandwich ELISA." Using this assay, the level of circulating antigen was elevated significantly in 23 of 30 sera from patients with ovarian carcinoma, as compared with 0 of 68 sera from healthy controls, 0 of 3 sera from patients with nonneoplastic diseases, and 25 of 75 sera from patients with other tumors. Soluble molecules of the mesothelin/MPF family may provide useful new marker(s) for diagnosis of ovarian carcinoma and/or monitoring its response to therapy.

Diagnosing gastrointestinal malignancies

OBJECTIVES

To provide an overview of imaging studies that can be used to help diagnose gastrointestinal malignancies and a brief description of tumor markers specific for these cancers.

DATA SOURCES

Published professional articles, textbooks, and clinical procedural manuals.

CONCLUSIONS

Diagnosing gastrointestinal malignancies can be problematic due to the relative lack of signs and symptoms, especially early in the disease process. While clinical suspicion may lead to a tentative diagnosis, imaging studies and tumor markers can provide confirmation of the suspected malignancy.

IMPLICATIONS FOR NURSING PRACTICE

An understanding of the requirements of imaging studies and tumor markers will allow for better preparation of the patient by the nurse for the test and can assist the nurse in helping the patient understand the need for and results of the diagnostic work-up.

Molecular genetics and in vitro sensitivity of a new human cell line, KKP, from a gastric adenocarcinoma

A new cancer cell line (KKP) was established from an ascitic effusion of an advanced gastric adenocarcinoma, intestinal type. The line has been maintained in continuous monolayer culture with a doubling time of 48 hours for more than 2 years. KKP cells, whose ultrastructural features are presented, showed an aneuploid DNA content, a modal number of 53 chromosomes, and the presence of one double minute chromosome. The karyotype showed trisomies of chromosomes 7, 12, 13, and 14, tetrasomy of chromosome 18, a reciprocal translocation [t(1;20)(q21;p11.2)], and a [t(4;?)] rearrangement. No amplification or rearrangements were evident in the c-MYC, c-ERB B2, H-RAS, INT-2, HST-1, c-MOS, and K-RAS genes, whereas somatic rearrangements were present in the sequences corresponding to c-MET and cyclin E genes by Southern blotting analysis. Polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis of P53 and RB genes did not reveal alterations or point mutations in the SSCP pattern of conformers. The chemosensitivity pattern assay of the KKP cell line indicated that it was sensitive to cisplatin, etoposide, and doxorubicin and resistant to 4'-hydroperoxycyclophosphamide. The clinical history of the patient from whom the cell line was derived is reported and compared with the results observed in the cell line in vitro. High levels of the tumor-associated antigens CEA (carcinoembryonic antigen) and CA19-9 were evident in the KKP cytosol, whereas the KKP spent culture medium maintained the same low levels of CEA and CA 19-9 found in the patient's serum. This new cell line may represent a useful tool for studying the biology of gastric cancer and for planning new therapeutic approaches.

Evidence for the upregulation of osteogenic protein-1 mRNA expression in musculoskeletal neoplasms

Little is known about bone and cartilage tumors at the molecular level; thus, the identification of genes associated with these tumors may be useful as markers and therapeutic targets. To address this issue and to test the hypothesis that abnormal expression of one or more growth factors in the transforming growth factor-beta superfamily is associated with musculoskeletal neoplasia, degenerate primers based on the conserved sequences in these genes were made for screening tumor samples by reverse transcription-polymerase chain reaction. First, these primers were used to obtain a comparative profile between a low-grade chondrosarcoma and its dedifferentiated high-grade counterpart in the same patient. This experiment identified an amplified DNA product in the high-grade sample that was identical to osteogenic protein-1/bone morphogenetic protein-7. Osteogenic protein-1 mRNA expression was 17-fold greater in this high-grade sample than in the low-grade one. Osteogenic protein-1 was highly expressed (three of three) in human osteosarcoma cell lines but was not expressed (zero of four) in normal osteoblast samples. Screening for gene expression of osteogenic protein-1 in 57 osteosarcomas and chondrosarcomas indicated that 44% (range: 38-52%) of them were positive for osteogenic protein-1 mRNA. Screening of breast and prostate tumors revealed a similar association with osteogenic protein-1 mRNA expression.