The prognostic significance of gastric juice CA 19-9 and CEA levels in gastric carcinoma patients

Detection of Aberrant Glycosylation of Serum Haptoglobin for Gastric Cancer Diagnosis Using a Middle-Up-Down Glycoproteome Platform

Gastric cancer is a frequently occurring cancer and is the leading cause of cancer-related deaths. Recent studies have shown that aberrant glycosylation of serum haptoglobin is closely related to gastric cancer and has enormous potential for use in diagnosis. However, there is no platform with high reliability and high reproducibility to comprehensively analyze haptoglobin glycosylation covering microheterogeneity to macroheterogeneity for clinical applications. In this study, we developed a middle-up-down glycoproteome platform for fast and accurate monitoring of haptoglobin glycosylation. This platform utilizes an online purification of LC for sample desalting, and an in silico haptoglobin glycopeptide library constructed by combining peptides and N-glycans to readily identify glycopeptides. In addition, site-specific glycosylation with glycan heterogeneity can be obtained through only a single MS analysis. Haptoglobin glycosylation in clinical samples consisting of healthy controls (n = 47) and gastric cancer patients (n = 43) was extensively investigated using three groups of tryptic glycopeptides: GP1 (including Asn184), GP2 (including Asn207 and Asn211), and GP3 (including Asn241). A total of 23 individual glycopeptides were determined as potential biomarkers (p < 0.00001). In addition, to improve diagnostic efficacy, we derived representative group biomarkers with high AUC values (0.929 to 0.977) through logistic regression analysis for each GP group. It has been found that glycosylation of haptoglobin is highly associated with gastric cancer, especially the glycosite Asn241. Our assay not only allows to quickly and easily obtain information on glycosylation heterogeneity of a target glycoprotein but also makes it an efficient tool for biomarker discovery and clinical diagnosis.

How to Best Exploit Immunotherapeutics in Advanced Gastric Cancer: Between Biomarkers and Novel Cell-Based Approaches

Despite extensive research efforts, advanced gastric cancer still has a dismal prognosis with conventional treatment options. Immune checkpoint inhibitors have revolutionized the treatment landscape for many solid tumors. Amongst gastric cancer subtypes, tumors with microsatellite instability and Epstein Barr Virus positive tumors provide the strongest rationale for responding to immunotherapy. Various predictive biomarkers such as mismatch repair status, programmed death ligand 1 expression, tumor mutational burden, assessment of tumor infiltrating lymphocytes and circulating biomarkers have been evaluated. However, results have been inconsistent due to different methodologies and thresholds used. Clinical implementation therefore remains a challenge. The role of immune checkpoint inhibitors in gastric cancer is emerging with data from monotherapy in the heavily pre-treated population already available and studies in earlier disease settings with different combinatorial approaches in progress. Immune checkpoint inhibitor combinations with chemotherapy (CT), anti-angiogenics, tyrosine kinase inhibitors, anti-Her2 directed therapy, poly (ADP-ribose) polymerase inhibitors or dual checkpoint inhibitor strategies are being explored. Moreover, novel strategies including vaccines and CAR T cell therapy are also being trialed. Here we provide an update on predictive biomarkers for response to immunotherapy with an overview of their strengths and limitations. We discuss clinical trials that have been reported and trials in progress whilst providing an account of future steps needed to improve outcome in this lethal disease.

Levels of malondialdehyde in the gastric juice: Its association with Helicobacter pylori infection and stomach diseases

BACKGROUND

Helicobacter pylori (H. pylori) infection causes elevation of lipid peroxidation product malondialdehyde (MDA) and this association may be due to the bacterium causing reactive oxygen species-mediated damage to DNA in the gastric epithelium. The aim of this study was to investigate the gastric juice MDA levels in relation to H. pylori infection and associated gastric diseases.

METHODS

Gastric juice samples were obtained from 117 patients undergoing endoscopy, and gastric juice MDA levels were determined by high-performance liquid chromatography (HPLC) system. We compared the MDA levels between patients with and without H. pylori infection and assessed the differences of MDA levels between chronic gastritis, gastric intestinal metaplasia, and gastric cancer postsurgical resection.

RESULTS

Malondialdehyde levels in gastric juice were significantly higher in chronic gastritis patients with H. pylori infection than in those without H. pylori infection (P < .0001). In patients without H. pylori infection, patients with gastric intestinal metaplasia and gastric cancer postsurgical resection had significantly higher gastric juice MDA level than patients with chronic gastritis. As a whole, patients with gastric intestinal metaplasia and gastric cancer postsurgical resection also had significantly higher MDA levels in gastric juice as compared to patients with chronic gastritis (P < .01). However, the difference of gastric juice MDA levels between gastric intestinal metaplasia and gastric cancer postsurgical resection was not significant.

CONCLUSION

Malondialdehyde in gastric juice could be used as a potential diagnostic biomarker for H. pylori infection and associated gastric diseases. The gastric juice MDA levels increased proportionally with the severity of gastric diseases.

Glycomic profiling of targeted serum haptoglobin for gastric cancer using nano LC/MS and LC/MS/MS

Gastric cancer has one of the highest cancer mortality rates worldwide, largely because of difficulties in early-stage detection. Aberrant glycosylation in serum proteins is associated with many human diseases including inflammation and various types of cancer. Serum-based global glycan profiling using mass spectrometry has been explored and has already led to several potential glycan markers for several disease states. However, localization of the aberrant glycosylation is desirable in order to improve the specificity and sensitivity for clinical use. Here, we combined protein-specific immunoaffinity purification, glycan release, and MS analysis to examine haptoglobin glycosylation of gastric cancer patients for glyco-markers. Age- and sex-matched 60 serum samples (30 cancer patients and 30 healthy controls) were used to profile and quantify haptoglobin N-glycans. A T-test based statistical analysis was performed to identify potential glyco-markers for gastric cancer. Interestingly, abundances of several tri- and tetra-antennary fucosylated N-glycans were increased in gastric cancer patients. Additionally, structural analysis via LC/MS/MS indicated that the fucosylated complex type N-glycans were primarily decorated with antenna fucose, which can be categorized as sialyl-Le^a or sialyl-Le^x type structures. This platform demonstrates quantitative, structure-specific profiling of haptoglobin glycosylation for the purposes of biomarker discovery for gastric cancer.

Detection of digestive malignancies and post-gastrectomy complications via gastrointestinal fluid examination

To date, gastric carcinoma (GC) is one of the common and fatal digestive malignancies worldwide. The prognosis of GC is not always satisfactory because of late diagnosis. Scholars are keen on discovering novel accurate and economical biomarkers in body liquids for GC screening to detect and evaluate the lesion before the results of imaging techniques are obtained. While traditional serum assays have limited sensitivity and specificity, gastrointestinal juice may provide relevant specific biomarkers because of its close contact with the tumor. Herein, the current progress in the relationship between gastrointestinal fluid analyses and GC is systematically and comprehensively reviewed. The detection of gastric juice pH, fluorescence spectrum, cytology, Helicobacter pylori-associated markers, nitrosamines, conventional tumor markers, amino acids, proteomics, microRNAs, long noncoding RNAs, protein-coding genes, vitamin C, etc., and combination tests of different category markers could provide important diagnostic and prognostic clues for gastrointestinal diseases. Particularly, early GC may be efficiently screened using gastric juice. Gastrointestinal fluid examination could also predict the adverse effects of postgastrectomy, such as pancreatic leakage, fistula, and abscess. Gastric fluid markers should be further studied to reveal the early predicators of malignancy and complications. The methods for obtaining the samples of gastrointestinal juice with minimum incision should also be comprehensively investigated.

Development of simultaneous analysis of tryptophan metabolites in serum and gastric juice - an investigation towards establishing a biomarker test for gastric cancer diagnosis

To evaluate changes in tryptophan metabolism and discover diagnostic biomarkers for gastric cancer, a quantitative method was developed for tryptophan and its seven metabolites (indole-3-lactic acid, anthranilic acid, serotonin, nicotinic acid, kynurenic acid, kynurenine and 3-indoxyl sulfate) in both human serum and gastric juice using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Serum and gastric juice were prepared with a simple protein precipitation using aqueous 0.1% formic acid and acetonitrile. As a result, it was found that the kynurenine pathway of tryptophan metabolism was activated in gastric cancer and that the metabolic ratio of kynurenine/tryptophan, which reflects the enzyme activity of indoleamine-2,3-dioxygenase, was associated with the observed metabolic changes. Finally, the investigation of tryptophan metabolites, especially kynurenic acid, in serum and gastric juice might serve as biomarkers for gastric cancer. The findings in this study provide critical information of tryptophan metabolism which can be applied to a serum-based diagnostic test for gastric cancer.

Detection of cancer cells and tumor markers in gastric lavage of patients with gastric cancer: Do these findings have a clinicopathological significance and oncological implication?

Although decreasing in the incidence over the last years, currently gastric adenocarcinoma represents the second cause of cancer related-death worldwide. Further knowledge and novel therapies are desperately needed in order to make the prognosis of these patients more acceptable. Infact, even though in recent years numerous staging parameters have been largely studied and unanimously recognized for their clinical and prognostic value, today too many shadows still exist around the capacity to predict exactly the natural history or post-treatment behavior of this cancer even among patients of the same stage. This study has identified the presence of isolated cancer cells as well as tumor markers (CEA, Ca 19.9, Ca 72.4 and Ca 50) from the gastric lavage of patients affected by gastric adenocarcinoma. Such findings led to the hypothesis that endoluminal exfoliation of neoplastic cells and the release of their products (tumor markers) into the gastric juice might be an expression of neoplastic behavior as well as aggressive malignancy. Should this hypothesis become a reality, some important progress could be made in the knowledge, staging, prediction as well as management and follow-up of this inauspicious type of cancer.

Analyzing Gastric Lavage of Gastric Cancer Patients: A Prospective Observational Study on Cytopathology and Determination of Intragastric CEA, CA 19.9, CA 72.4, and CA 50

OBJECTIVES

To investigate gastric lavage (GL) cytopathology and immunometric analysis as novel clinicopathologic and prognostic parameters for gastric cancer (GC).

STUDY DESIGN

In 38 patients with gastric adenocarcinoma, we performed a cytopathologic analysis and an immunometric assay of GL using four tumor markers (CEA, CA 19.9, CA 72.4, and CA 50). The intragastric tumor marker levels were compared with a control group consisting of 41 non-GC patients to determine a statistically significant cutoff value.

RESULTS

GL cytopathology demonstrated the presence of cancer cells in 13 (34.2%) of the 38 GC patients: such a finding correlated to the parameters pT and pN with a statistically significant validity (p < 0.0267 and p < 0.0306, respectively). Measurement of intragastric CA 19.9 and CA 50 attained a statistically significant cutoff value (p < 0.002 and p < 0.0096, respectively), which was invalidated by the low sensitivity of the ROC curve analysis.

CONCLUSIONS

In contrast to determination of its tumor markers, GL cytopathology correlated well with pT and pN staging parameters. Should this and other features be corroborated by future studies, the GL cytology test could be routinely used to detect aggressive types of GC even at early stages and result in important progress in the knowledge, staging, prediction, as well as management and follow-up of this inauspicious type of cancer.

A Novel Electrochemical Microfluidic Chip Combined with Multiple Biomarkers for Early Diagnosis of Gastric Cancer

Early diagnosis is very important to improve the survival rate of patients with gastric cancer and to understand the biology of cancer. In order to meet the clinical demands for early diagnosis of gastric cancer, we developed a disposable easy-to-use electrochemical microfluidic chip combined with multiple antibodies against six kinds of biomarkers (carcinoembryonic antigen (CEA), carbohydrate antigen 19-9 (CA19-9), Helicobacter pylori CagA protein (H.P.), P53oncoprotein (P53), pepsinogen I (PG I), and PG-II). The six kinds of biomarkers related to gastric cancer can be detected sensitively and synchronously in a short time. The specially designed three electrodes system enables cross-contamination to be avoided effectively. The linear ranges of detection of the electrochemical microfluidic chip were as follows: 0.37-90 ng mL(-1) for CEA, 10.75-172 U mL(-1) for CA19-9, 10-160 U L(-1) for H.P., 35-560 ng mL(-1) for P53, 37.5-600 ng mL(-1) for PG I, and 2.5-80 ng mL(-1)for PG II. This method owns better sensitivity compared with enzyme-linked immunosorbent assay (ELISA) results of 394 specimens of gastric cancer sera. Furthermore, we established a multi-index prediction model based on the six kinds of biomarkers for predicting risk of gastric cancer. In conclusion, the electrochemical microfluidic chip for detecting multiple biomarkers has great potential in applications such as early screening of gastric cancer patients, and therapeutic evaluation, and real-time dynamic monitoring the progress of gastric cancer in near future.

Proteomics in gastric cancer research: Benefits and challenges

Among various cancers, gastric cancer (GC) exhibits relatively high morbidity and mortality rate worldwide. The lack of effective methods in early detection and diagnosis, and immediate therapies makes treating such disease a challenge for both clinicians and oncologists. Proteomics has emerged as a promising technology platform for rationally identifying biomarkers and novel therapeutic targets for GC, as well as discovering underlying mechanisms of carcinogenesis. Its application has greatly benefited mechanistic studies of this disease. This review will demonstrate the applications of proteomic technology in GC research. The advantages and shortcomings of this technology, as reflected by current studies, will also be discussed to improve and expand its application in the field of cancer research.

The prognostic significance of pretreatment serum CEA levels in gastric cancer: a meta-analysis including 14651 patients

BACKGROUND

Carcinoembryonic antigen (CEA) is commonly used as a serum tumor marker in clinical practice; however, its prognostic value for gastric cancer patients remains uncertain. This meta-analysis was performed to assess the prognostic value of CEA and investigate CEA as a tumor marker.

METHODS

PubMed, EMBASE and other databases were searched for potentially eligible studies. Forty-one studies reporting the prognostic effect of pretreatment serum CEA expression in gastric cancer patients were selected. Data on 14651 eligible patients were retrieved for the meta-analysis. Based on the data extracted from the available literature, the hazard ratio (HR) and 95% confidence interval (CI) for an adverse prognosis were estimated for gastric cancer patients with elevated pretreatment serum levels of CEA (CEA+) relative to patients with normal pretreatment CEA levels (CEA-).

RESULTS

The CEA+ patients had a significantly poorer prognosis than the CEA- patients in terms of overall survival (OS: HR 1.716, 95% CI 1.594 - 1.848, P< 0.001), disease-specific survival (DSS: HR 1.940, 95% CI 1.563 - 2.408, P< 0.001), and disease-free survival (DFS: HR 2.275, 95% CI 1.836 - 2.818, P< 0.001). Publication bias and an influence of different cut-off values were not observed (all P> 0.05). In the pooled analyses of multivariate-adjusted HRs, the results suggested that pretreatment serum CEA may be an independent prognostic factor in gastric cancer (OS: HR 1.681, 95% CI 1.425 - 1.982; DSS: HR 1.900, 95% CI 1.441 - 2.505; DFS: HR 2.579, 95% CI 1.935 - 3.436).

CONCLUSION/SIGNIFICANCE

The meta-analysis based on the available literature supported the association of elevated pretreatment serum CEA levels with a poor prognosis for gastric cancer and a nearly doubled risk of mortality in gastric cancer patients. CEA may be an independent prognostic factor for gastric cancer patients and may aid in determining appropriate treatment which may preferentially benefit the CEA+ patients.

Unsaturated free fatty acids: a potential biomarker panel for early detection of gastric cancer

Changes in the levels of free fatty acids (FFAs) are closely associated with physiological status. Serum levels of C16:1, C18:3, C18:2, C18:1, C20:4, and C22:6 in 164 gastric cancer (GC) patients and 111 benign gastric disease (BGD) patients were significantly decreased compared with 252 healthy controls. Receiver operating characteristic analysis showed that the biomarker panel including C16:1, C18:3, C18:2, C20:4, and C22:6 presents a high diagnostic ability to differentiate early-stage GC patients from healthy controls plus BGD patients, with a sensitivity of 80.6% and a specificity of 72.7%.

Gastric juice long noncoding RNA used as a tumor marker for screening gastric cancer

BACKGROUND

Long noncoding RNAs (lncRNAs) play a crucial role in tumorigenesis. However, the value of lncRNAs in the diagnosis of gastric cancer remains unknown. To identify whether lncRNA-AA174084 is a potential marker for the early diagnosis of gastric cancer (GC), the authors investigated its levels in tissues, blood, and gastric juices from patients with various stage of gastric tumorigenesis.

METHODS

Total RNA in 860 specimens from patients and healthy controls was extracted. Levels of AA174084 in 134 paired GC tissues, 127 gastric mucosal tissues, 335 plasma samples, and 130 gastric juice samples at each stage of gastric tumorigenesis were measured using real-time reverse transcriptase-polymerase chain reaction analysis. The potential association between AA174084 levels and patients' clinicopathologic features were analyzed. A receiver operating characteristic (ROC) curve was constructed for differentiating GC patients from controls.

RESULTS

Expression levels of AA174084 were down-regulated significantly in 95 of 134 GC tissues (71%) compared with the levels in paired, adjacent, normal tissues (P < .001). AA174084 levels had significant, negative correlations with age (P = .031), Borrmann type (P = .016), and perineural invasion (P = .032). Plasma AA174084 levels in patients with GC dropped markedly on day 15 after surgery compared with preoperative levels (P < .001) and were associated with invasion (P = .049) and lymphatic metastasis (P = .042). AA174084 levels in gastric juice from patients with GC were significantly higher than the levels in normal mucosa or in patients with minimal gastritis, gastric ulcers, and atrophic gastritis (P < .001). The area under ROC was up to 0.848 (P < .001).

CONCLUSIONS

AA174084 may have potential as marker for the early diagnosis of GC.

Serum carbohydrate antigen 19-9 and prognosis of patients with gastric cancer

Previous studies have assessed the prognostic role of serum carbohydrate antigen 19-9 (CA 19-9) concentration in patients with gastric cancer, but the findings from those studies were inconsistent. We searched the PubMed and Web of Science databases to find eligible studies assessing the prognostic role of CA 19-9 in patients with gastric cancer. Twelve studies with a total of 5,072 gastric cancer patients were finally included into the meta-analysis. The pooled hazard ratio (HR) with corresponding 95 % confidence interval (95 % CI) for overall survival were calculated to assess the prognostic role of CA 19-9 in patients with gastric cancer. Overall, elevated serum concentration of CA 19-9 (>37 U/mL) was associated with poorer overall survival in patients with gastric cancer (fixed-effects HR = 1.36, 95 % CI 1.24-1.48, P < 0.001). Subgroup analysis by study design further showed that elevated serum concentration of CA 19-9 was associated with poorer overall survival in patients with gastric cancer. There was no obvious risk of publication bias. Elevated concentration of serum CA 19-9 is associated with poorer overall survival in patients with gastric cancer.

Level of circulating PD-L1 expression in patients with advanced gastric cancer and its clinical implications

OBJECTIVE

The programmed cell death-1 receptor/programmed cell death-1 ligand (PD-1/PD-L1) pathway plays a crucial role in tumor evasion from host immunity. This study was designed to evaluate the association between circulating PD-L1 expression and prognosis in patients with advanced gastric cancer.

METHODS

Totally 80 advanced gastric cancer patients and 40 health controls from Beijing Cancer Hospital were enrolled in the present study. Circulating PD-L1 expression was tested by enzyme-linked immunosorbent assay (ELISA). The associations between the expression level of PD-L1 and clinicopathological features and prognosis were analyzed statistically.

RESULTS

Expression of PD-L1 in advanced gastric cancer patients was significantly up-regulated compared with health people (P=0.006). The expression of PD-L1 was significantly correlated with differentiation and lymph node metastasis (P=0.026 and P=0.041, respectively). Although we didn't find significant difference in all advanced gastric cancer patients with different PD-L1 expression, the adenocarcinoma patients with higher up-regulated PD-L1 expression had much better prognosis than low expression patients (65.6% vs. 44.7%, P=0.028).

CONCLUSIONS

PD-L1 was elevated in advance gastric cancer patients and may play an important role in tumor immune evasion and patients prognosis.

High level of preoperative carbohydrate antigen 19-9 is a poor survival predictor in gastric cancer

AIM: To assess the clinical significance and the prognostic value of preoperative serum carbohydrate antigen 19-9 (CA 19-9) level in gastric cancer.

METHODS: Between January 2005 and December 2006, 1960 patients underwent surgery for histologically confirmed gastric cancer. Of these, 163 patients had elevated serum levels of CA 19-9 preoperatively, and 1628 patients had normal serum levels of CA 19-9 preoperatively. For this study, 325 patients were selected from the group of 1628 patients by age, sex, and cancer stage to serve as controls. Statistically significant differences in survival rates were calculated using the log-rank test. A P value less than 0.05 was considered statistically significant and was determined using SAS software.

RESULTS: The baseline characteristics showed some differences between the two groups with regard to histology. Overall survival (OS) in the elevated and non-elevated group was 37.90 and 68.67 mo, respectively (P < 0.001). N stage (P = 0.001) was a significant predictor of disease-free survival by multivariate analysis. Also, N stage (P < 0.001), and the presence of peritoneal metastasis (P < 0.001) remained independent factors in predicting OS by multivariate analysis. Additionally, preoperative serum CA 19-9 levels were significantly associated with OS in univariate (P = 0.009) and multivariate (P = 0.021) analyses.

CONCLUSION: Serum CA 19-9 can be considered an independent prognostic factor in predicting OS in patients anticipating surgery for gastric cancer.

A novel approach for the detection of early gastric cancer: fluorescence spectroscopy of gastric juice

OBJECTIVE

This study aimed to investigate the efficacy of fluorescence spectroscopy of gastric juice for early gastric cancer (EGC) screening.

METHODS

Gastric juice was collected from 101 participants who underwent endoscopy in the Outpatient Endoscopy Center of Peking University Third Hospital. The participants were divided into three groups: the normal mucosa or chronic non-atrophic gastritis (NM-CNAG) group (n = 35), advanced gastric cancer (AGC) group (n = 33) and EGC group (n = 33). Fluorescence spectroscopic analysis was performed in all the gastric juice samples and the maximum fluorescence intensity of the first peak (P1 FI) was measured.

RESULTS

The mean fluorescence intensity of P1 FI of gastric juice in AGC (92.1 ± 10.7) and EGC (90.8 ± 12.0) groups was significantly higher than that in the NM-CNAG group (55.7 ± 7.5) (AGC vs NM-CNAG, P = 0.006 and EGC vs NM-CNAG, P = 0.015, respectively). The areas under the receiver operating characteristic curves for the detection of AGC and EGC were 0.681 (95% confidence interval [CI] 0.553-0.810, P = 0.010) and 0.655 (95% CI 0.522-0.787, P = 0.028). With the P1 FI of ≥47.7, the sensitivity, specificity and accuracy for detecting EGC were 69.7%, 57.1% and 63.2%, respectively.

CONCLUSIONS

The enhancement of P1 FI of gastric juice occurs at the early stage of gastric cancer. Fluorescence spectroscopy of gastric juice may be used as a novel screening tool for the early detection of gastric cancer.

The gastric fluid proteome as a potential source of gastric cancer biomarkers

Gastric cancer is a significant cause of death in many parts of the world. Although timely intervention is associated with better clinical outcome, early gastric cancer detection is frequently not possible given its asymptomatic nature. As such, sensitive and specific gastric cancer biomarkers are highly sought after as diagnostic surrogates that may replace invasive endoscopic and histological examinations. Unlike gastric cancer tissue and serum which are heterogeneous and overloaded with abundant proteins, the gastric fluid contains a concentrated molecular biopsy of the stomach that accurately reflects gastric oncology. This review attempts to (i) summarise the state of proteomics-based gastric cancer biomarker discovery from patient gastric fluids, (ii) outline key considerations in working with the body fluid, and (ii) discuss how the challenges in gastric cancer diagnosis may be overcome with new perspectives in gastric cancer screening.

Gastric juice miR-129 as a potential biomarker for screening gastric cancer

MicroRNAs (miRNAs) play crucial roles during the occurrence and development of gastric cancer. Conventional serological tests for screening gastric cancer have limits on sensitivity and specificity. Several miRNAs in peripheral blood have been used as biomarkers of gastric cancer. However, most of these miRNAs are shared by several types of cancer. Thanks to the tissue specificity of gastric juice, here we examined the feasibility of using gastric juice miR-129-1/2, which are aberrantly expressed in gastric cancer, to screen gastric cancer. Total of 141 gastric juices samples from gastric cancer, gastric ulcer, atrophic gastritis, and minimal gastritis patients or subjects with normal mucosa were collected by gastroscopy. The gastric juice miR-129-1/2 levels were detected by quantitative reverse transcription-polymerase chain reaction. A receiver operating characteristic (ROC) curve was constructed for differentiating patients with gastric cancer from patients with benign gastric diseases. We showed that, compared with patients with benign gastric diseases, patients with gastric cancer had significantly lower levels of gastric juice miR-129-1-3p and miR-129-2-3p. The areas under ROC curve (AUC) were 0.639 and 0.651 for miR-129-1-3p and miR-129-2-3p, respectively. Using the parallel combination test, the AUC was up to 0.656. In summary, our results suggest that gastric juice miR-129-1-3p and miR-129-2-3p are potential biomarkers for the screening gastric cancer, and the detection of gastric juice miRNAs is a convenient non-invasion method for the diagnosis of gastric cancer.

High levels of aromatic amino acids in gastric juice during the early stages of gastric cancer progression

Background

Early-stage gastric cancer is mostly asymptomatic and can easily be missed easily by conventional gastroscopy. Currently, there are no useful biomarkers for the early detection of gastric cancer, and their identification of biomarkers is urgently needed.

Methods

Gastric juice was obtained from 185 subjects that were divided into three groups: non-neoplastic gastric disease (NGD), advanced gastric cancer and early gastric cancer (EGC). The levels of aromatic amino acids in the gastric juice were quantitated using high-performance liquid chromatography.

Results

The median values (25th to 75th percentile) of tyrosine, phenylalanine and tryptophan in the gastric juice were 3.8 (1.7–7.5) µg/ml, 5.3 (2.3–9.9) µg/ml and 1.0 (0.4–2.8) µg/ml in NGD; 19.4 (5.8–72.4) µg/ml, 24.6 (11.5–73.7) µg/ml and 8.3 (2.1–28.0) µg/ml in EGC. Higher levels of tyrosine, phenylalanine and tryptophan in the gastric juice were observed in individuals of EGC groups compared those of the NGD group (NGD vs. EGC, P<0.0001). For the detection of EGC, the areas under the receiver operating characteristic curves (AUCs) of each biomarker were as follows: tyrosine, 0.790 [95% confidence interval (CI), 0.703–0.877]; phenylalanine, 0.831 (95% CI, 0.750–0.911); and tryptophan, 0.819 (95% CI, 0.739–0.900). The sensitivity and specificity of phenylalanine were 75.5% and 81.4%, respectively, for detection of EGC. A multiple logistic regression analysis showed that high levels of aromatic amino acids in the gastric juice were associated with gastric cancer (adjusted β coefficients ranged from 1.801 to 4.414, P<0.001).

Conclusion

Increased levels of tyrosine, phenylalanine and tryptophan in the gastric juice samples were detected in the early phase of gastric carcinogenesis. Thus, tyrosine, phenylalanine and tryptophan in gastric juice could be used as biomarkers for the early detection of gastric cancer. A gastric juice analysis is an efficient, economical and convenient method for screening early gastric cancer development in the general population.

CA72-4 may contribute to real-time reconnaissance of gastric cancer

Objective: Data from prospective studies indicate a positive impact of gastric cancer screening programs on mortality associated with the disease. Unfortunately, endoscopic procedures, widely regarded as uncomfortable, face low patient compliance, thus underscoring the need for reliable biological markers capable of detection of tumor growth in bodily fluids. Furthermore, in light of the emerging patient-friendly, still devoid of histopathological capabilities, capsule endoscopy, gastric fluid may prove valuable for biomarker-assisted cancer diagnosis. We set out to determine whether CA72-4 measurement in gastric fluid may be of benefit for detection of gastric cancer.Design: Open prospective study.Setting: Sample collection was performed at a tertiary referral center for patients with gastroenterological diseases; immunological analysis was performed at the R&D facility of a commercial biotechnology company. Studies were part of an EU-FP6 project (NEMO).Patients: 176 patients referred for endoscopy due to gastrointestinal complaints.Interventions: Gastric juice was aspirated endoscopically according to standard operating procedures, volume and pH were measured immediately and samples stored at -80°C.Outcome measures: Concentration of CA72-4 tumor marker was evaluated by enzyme-linked immunosorbent assay (ELISA).Results: Median CA72-4 levels were about 4-fold higher in cancer patients compared with patients with normal gastric findings, gastric inflammation, intestinal metaplasia or other diseases (p=0.001). Multivariate linear regression analysis revealed that elevated CA72-4 was significantly predicted by gastric carcinoma adjusted for H. pylori status, age, smoking status, PPI dose, and pH of aspirate (R2=0.27, p<0.0001). In this model, diagnosis of gastric carcinoma had by far the greatest influence. At a cut-off level of 100 U/ml, CA72-4 had 75% sensitivity and 89% specificity for detection of gastric cancer.Conclusions: Based on our findings, CA72-4 level assessment in gastric fluid, featuring yet unmatched accuracy of malignant neoplasia detection may prove beneficial for gastric cancer screening.

Observation of peptide differences between cancer and control in gastric juice

Biomarkers for various diseases have been extensively searched for the past 5 years. Nevertheless, most efforts were focused on the search for protein biomarkers from serum samples. In this work, we tried to look for peptide biomarkers from gastric juice samples with MALDI-TOF-MS. More than 200 gastric juice samples from healthy people, gastric ulcer patients, duodenal ulcer patients, and cancer patients were examined. There were clear pattern differences of mass spectra among samples from healthy people and patients with different gastric diseases. We found five peptides for gastric cancer diagnosis with high sensitivity and specificity. Sequences of these five peptides, including two pepsinogen fragments, leucine zipper protein fragment, albumin fragment, and α-1-antitrypsin fragment, have been identified by mass spectrometric analysis and immuno-deplete assay with antibodies.

Advances in proteomics of digestive juices for the diagnosis of digestive system malignancies

Body fluid proteomic analysis is a new technology and strategy for disease diagnosis and treatment. Blood is the most commonly used specimen in body fluid proteomics, but as a systemic fluid, it has limitations because of complex composition and low abundance of disease-related proteins. In contrast, local body fluids are closest to the lesions, contain more pathological information, and therefore are more valuable in clinical proteomics. In the digestive system, there are a variety of body fluids which are considered potential reservoirs of biomarkers for their quality and quantity of proteins will alter during lesions occurring in corresponding organs. In recent years, more and more clinical proteomic analyses of saliva, gastric juice, bile and pancreatic juice has been reported and the proteins related to digestive cancers have been found, and some proteins show application potentials in cancer diagnosis. However, the proteomic analyses of digestive juices are facing technical challenges in terms of the reproducibility of results and standardization of specimen handling.

Three aromatic amino acids in gastric juice as potential biomarkers for gastric malignancies

For screening early-stage gastric malignancies, the existing serum biomarkers have limited sensitivity and specificity. Gastric juice biomarkers are scarce and require further investigation. We divided this study on searching potential biomarkers into four parts: (1) detection of differential fluorescence spectrum and peaks in the gastric juice from patients using fluorescence spectroscopy and HPLC, (2) identification and validation of differential peaks using LC/MS and NMR, (3) quantification of potential biomarkers, and (4) establishment of diagnostic detection. The fluorescence intensity (FI), tyrosine, phenylalanine, tryptophan and total protein content were significantly higher in the gastric juice of patients with gastric malignancies (all P<0.01). With all P<0.001, the areas under the receiver operating characteristic curves of the biomarkers were tyrosine, 0.838; phenylalanine, 0.856; and tryptophan, 0.816. At a specificity of 79.4%, the sensitivity for gastric malignancy detection with phenylalanine was 87.9% only. Aromatic amino acids in gastric juices could be used as potential diagnostic biomarkers to screen gastric malignancies. It is a less-invasive and economical method compared to gastric biopsy.

The distinctive gastric fluid proteome in gastric cancer reveals a multi-biomarker diagnostic profile

BACKGROUND

Overall gastric cancer survival remains poor mainly because there are no reliable methods for identifying highly curable early stage disease. Multi-protein profiling of gastric fluids, obtained from the anatomic site of pathology, could reveal diagnostic proteomic fingerprints.

METHODS

Protein profiles were generated from gastric fluid samples of 19 gastric cancer and 36 benign gastritides patients undergoing elective, clinically-indicated gastroscopy using surface-enhanced laser desorption/ionization time-of-flight mass spectrometry on multiple ProteinChip arrays. Proteomic features were compared by significance analysis of microarray algorithm and two-way hierarchical clustering. A second blinded sample set (24 gastric cancers and 29 clinically benign gastritides) was used for validation.

RESULTS

By significance analysyis of microarray, 60 proteomic features were up-regulated and 46 were down-regulated in gastric cancer samples (p < 0.01). Multimarker clustering showed two distinctive proteomic profiles independent of age and ethnicity. Eighteen of 19 cancer samples clustered together (sensitivity 95%) while 27/36 of non-cancer samples clustered in a second group. Nine non-cancer samples that clustered with cancer samples included 5 pre-malignant lesions (1 adenomatous polyp and 4 intestinal metaplasia). Validation using a second sample set showed the sensitivity and specificity to be 88% and 93%, respectively. Positive predictive value of the combined data was 0.80. Selected peptide sequencing identified pepsinogen C and pepsin A activation peptide as significantly down-regulated and alpha-defensin as significantly up-regulated.

CONCLUSION

This simple and reproducible multimarker proteomic assay could supplement clinical gastroscopic evaluation of symptomatic patients to enhance diagnostic accuracy for gastric cancer and pre-malignant lesions.

Review of a current role of mass spectrometry for proteome research

This review is intended to give readers a snapshot of current mass spectrometry for proteomics research. It covers a brief history of mass spectrometry proteomic research, peptidomics and proteomics for biomarker search, quantitative proteomics, proteomics with post-translational modification and future perspective of proteomics.

Gastrointestinal fluids proteomics

Seventy million people suffer from diseases of the gastrointestinal tract annually in US, translating to US$85.5 billion in direct healthcare costs. The debilitating effects of these gastrointestinal (GI) diseases can be circumvented with good biomarkers for early detection of these disorders, which will greatly increase the success of curative treatments. GI fluids represent a potential reservoir of biomarkers for early diagnosis of various GI and systemic diseases since these fluids are the most proximal fluid bathing diseased cells. They are anticipated to have proteomes that closely reflect the ensemble of proteins secreted from the respective GI tissues. Most importantly, the disease markers present in GI fluids should be present in higher concentrations than in sera, thus offering greater sensitivity in their detection. However, proteome analysis of GI fluids can be complex mainly due to the dynamic range of protein content and the numerous PTMs of proteins in each specialized GI compartment. This review attempts to discuss the physiology of the various GI fluids, the special technical considerations required for proteome analysis of each fluid, as well as to summarize the current state of knowledge of biomarker discoveries and clinical utility of GI fluids such as salivary, gastric, pancreatic, and biliary secretions.

Early advances of α1-antitrypsin precursor using the proteomic approach in gastric juice

Evaluation of: Hsu PI, Chen CH, Hsieh CS et al.: α1-antitrypsin precursor in gastric juice is a novel biomarker for gastric cancer and ulcer. Clin. Cancer Res. 13(3), 876–883 (2007) [1] . The authors have identified the α1-antitrypsin precursor as a new protein marker of gastric cancer in gastric juice by 2D electrophoresis gel and mass spectrometric analyses. Three different pathologic classes of patients were considered with duodenal ulcer, gastric ulcer and gastric cancer and compared with healthy cases. α1-antitrypsin precursor was present, like the main peptide, in the specific band pattern, and seemed to be more expressed not only in advanced gastric cancer, but also in early forms of tumor. The study provides a fine contribution to this field of medicine, significantly correlating the α1-antrypsin precursor with gastric hypoacidity, gastric ulcer and gastric cancer. In addition, the utilization of gastric juice for biomarker recognition avoids the invasive resection of tissues. In conclusion, the research underlines, with an innovative and thorough approach, the role of the α1-antitrypsin precursor as a valid biomarker in gastric cancer and ulcers. However, it does not contribute to the advancement of research aimed at discovering the possible origin of the protein, and this could be the aim of future investigations.

Alpha1-antitrypsin precursor in gastric juice is a novel biomarker for gastric cancer and ulcer

PURPOSE

To search for novel disease-specific markers in gastric juice by investigating the protein concentrations and components in gastric juice from patients with various gastroduodenal diseases.

EXPERIMENTAL DESIGN

Protein concentrations and pH values in fasting gastric juice were examined in 120 healthy subjects and 39 gastric ulcer, 38 duodenal ulcer, and 31 gastric cancer patients. The protein components in gastric juice were studied by two-dimensional PAGE and mass spectrometric analysis.

RESULTS

Protein concentrations in gastric juice of patients with gastric ulcers and gastric cancer were significantly higher than those in healthy subjects (1.06 and 2.61 mg/mL versus 0.48 mg/mL; P=0.001 and P<0.001, respectively), and duodenal ulcer patients had lower gastric juice protein concentrations compared with healthy subjects (0.26 versus 0.48 mg/mL; P<0.05). Gastric hypoacidity and advanced age were independent factors affecting the protein concentrations in gastric juice with odds ratios of 32.9 (95% confidence interval, 11.8-90.9) and 3.2 (95% confidence interval, 1.3-8.3), respectively. Each electrophoresis images of gastric juice could be classified into one of three patterns: basic band, specific band, or nonspecific band. The frequencies of specific band pattern in healthy subjects, gastric ulcer, duodenal ulcer, and gastric cancer patients were 6%, 42%, 6%, and 93%, respectively. Proteomic analysis revealed that alpha1-antitrypsin precursor was the principal peptide in the specific band.

CONCLUSIONS

alpha1-antitrypsin precursor in gastric juice is a novel biomarker for gastric cancer and ulcer. A noninvasive method to obtain gastric juice followed by proteomic analysis may serve as a new tool to screen for gastric malignancies.