Optimized Categorical Boosting for Gastric Cancer Classification using Heptagonal Reinforcement learning and the Water Optimization Algorithm

Circulating cell free DNA (cfDNA) has been suggested as a novel biomarker for the early detection of cancer. Therefore, we investigated whether the methylation pattern of promoters of critical genes in cfDNA can be a useful marker for the early detection of gastric cancer and the therapeutic effects of treatment. In this casecontrol study, the methylation status of 32 cancer associated genes from 41 gastric cancer patients and 104 healthy control subjects were measured by methylation-specific PCR. We found that 15 out of 32 cancer-associated genes were hypermethylated in cancer patients compared to those of the controls. Further, we found that a gene panel of PYCARD, APAF1, MINT1, and BRCA1 genes showed 97.6% sensitivity and 66.3% specificity for the presence of gastric cancer. Lastly, we found that 22 initially methylated genes became unmethylated after surgical resection of the tumor (p< 0.05). The aberrant methylation pattern of tumor suppressor genes can be reliable biomarkers for the early detection of gastric cancer and of the efficacy of surgical resection.

134P - Identification, development and validation of a circulating miRNA-based diagnostic signature for early detection of gastric cancer

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Early detection and accurate preoperative staging of gastric cancer are clinically important because the prognosis and choice of an optimal therapeutic approach are directly related to the stage of a neoplasm at time of presentation. Multidetector row computed tomography is a potentially powerful tool for noninvasive gastric evaluation. When thin collimation is used, near-isotropic imaging of the stomach is possible. Proper air distention of the stomach is used with virtual gastroscopic images; the technique is able to evaluate endoluminal lesions of the stomach and assist in early detection of gastric cancer. Adequate water-filled dynamic multiplanar reformatted images allow the radiologist to choose the optimal imaging plane to accurately evaluate depth of tumor invasion of the gastric wall and perigastric fat plane infiltration, identify a thin fat plane between a tumor and adjacent organs, avoid partial volume averaging effects, and better differentiate lymph nodes from small perigaskric vessels. Thus, the combination of air distention and hydrodistention of the stomach and dynamic contrast-enhanced multidetector row computed tomography with near-isotropic imaging offer improved diagnosis and staging of gastric cancers.

BackgroundEarly-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.MethodsGastric 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.ResultsThe 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).ConclusionIncreased 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.

Autoantibodies against tumor-associated antigens (TAAs) have been suggested as biomarkers for early detection of gastric cancer. However, studies that systematically assess the diagnostic performance of a large number of autoantibodies are rare. Here, we used bead-based multiplex serology to simultaneously measure autoantibody responses against 64 candidate TAAs in serum samples from 329 gastric cancer patients, 321 healthy controls and 124 participants with other diseases of the upper digestive tract. At 98% specificity, sensitivities for the 64 tested autoantibodies ranged from 0–12% in the training set and a combination of autoantibodies against five TAAs (MAGEA4 + CTAG1 + TP53 + ERBB2_C + SDCCAG8) was able to detect 32% of the gastric cancer patients at a specificity of 87% in the validation set. Sensitivities for early and late stage gastric cancers were similar, while chronic atrophic gastritis, a precursor lesion of gastric cancer, was not detectable. However, the 5-marker combination also detected 26% of the esophageal cancer patients. In conclusion, the tested autoantibodies and combinations alone did not reach sufficient sensitivity for gastric cancer screening. Nevertheless, some autoantibodies, such as anti-MAGEA4, anti-CTAG1 or anti-TP53 and their combinations could possibly contribute to the development of cancer early detection tests (not necessarily restricted to gastric cancer) when being combined with other markers.

Gastric cancer is the second leading cause of cancer death in the world, and effective diagnosis is extremely important for good outcome. We assessed the diagnostic potential of an autoantibody panel that may provide a novel tool for the early detection of gastric cancer. We analyzed data from patients with gastric cancer and normal controls in test and validation cohorts. Autoantibody levels were measured against a panel of six tumor‐associated antigens (TAAs) by ELISA: p53, heat shock protein 70, HCC‐22‐5, peroxiredoxin VI, KM‐HN‐1, and p90 TAA. We assessed serum autoantibodies in 100 participants in the test cohort. The validation cohort comprised 248 participants. Autoantibodies to at least one of the six antigens showed a sensitivity/specificity of 49.0% (95% confidence interval [CI], 39.2–58.8%)/92.4% (95% CI, 87.2–97.6%), and 52.0% (95% CI, 42.2–61.8%)/90.5% (95% CI, 84.8–96.3%) in the test and validation cohorts, respectively. In the validation cohort, no significant differences were seen when patients were subdivided based on age, sex, depth of tumor invasion, lymph node metastasis, distant metastasis, peritoneal dissemination, or TNM stage. Patients who were positive for more than two antibodies in the panel tended to have a worse prognosis than those who were positive for one or no antibody. Measurement of autoantibody response to multiple TAAs in an optimized panel assay to discriminate patients with early stage gastric cancer from normal controls may aid in the early detection of gastric cancer.

Antibodies against tumor-associated antigens have been found in serum of patients with various types of cancers and may serve as biomarkers for early detection of gastric cancer as well. This systematic review aims to give an overview about known autoantibodies and their diagnostic value in gastric cancer. We conducted a systematic literature search in two databases to identify studies which performed serological testing for autoantibodies in gastric cancer patients and controls. Data on study characteristics and results were extracted independently by two reviewers. Overall, 39 articles reporting the detection of 34 different autoantibodies met the inclusion criteria for this review. The most common antibody detection method was enzyme-linked immunosorbent assay and the most frequently assessed autoantibody was anti-p53, which was tested in 13 studies. Most antibodies were assessed in only one study and only few authors have evaluated the diagnostic value of combinations of multiple autoantibodies. For single autoantibodies, specificity was generally very high (median: 99.15%), but sensitivity was mostly rather low (median: 12.35%). For some autoantibody combinations, substantially higher sensitivity at reasonably high levels of specificity could be achieved. Development of extended and optimized multimarker panels of autoantibodies might be a promising approach for gastric cancer early detection.

This paper introduces a new method for the early detection of gastric cancer using a combination of feature extraction based on discrete wavelet transformation (DWT) for horizontal attenuated total reflectance–Fourier transform infrared spectroscopy (HATR–FT-IR) and classification using probability neural network (PNN). 344 FT-IR spectra were collected from 172 pairs of fresh normal and abnormal stomach tissue᾽s samples. After preprocessing, 5 features were extracted with DWT analysis. Based on the PNN classification, all FT-IR spectra were classified into three categories. The accuracy of identifying normal gastric tissue, early gastric cancer tissue and gastric cancer tissue samples were 100.00, 97.56 and 100.00%, respectively. This result indicated that FT-IR with DWT and PNN could effectively and easily diagnose gastric cancer in its early stages.

10559 Background: Gastric cancer is one of the most common malignancy in the world and one of the leading causes of cancer related death in Korea. Most treatments for advanced gastric cancer have limited efficacy. So early detection of gastric cancer could have profound impact on the successful treatment. Application of multiple biomarkers may improve the diagnostic prediction to distinguish cancer from non-cancer. ProteinChip Surface-Enhanced Laser Desorption/Ionization Time-of-flight Mass Spectrometry (SELDI-TOF-MS) system is one of the currently used techniques to identify biomarkers for cancers. In this study, we have explored whether the serum proteomic patterns by ProteinChip SELDI system can differentiate gastric cancers from non-cancer cohorts. Methods: We have screened protein profiles of 100 serum samples obtained from 60 gastric cancer patients and 40 healthy individuals. Protein expression profiles were expressed on ProteinChip Array and analyzed by PreoteinChip Reader. Peak intensities were normalized by total ion currency and analyzed by the Biomarker Wizard Software to identify the peaks showing significantly different intensities between normal and cancer groups. Classification analysis and construction of decision trees were done with the Biomarker Pattern Software. Results: SELDI -TOF-MS by averaging 50 laser spots collected at a laser intensity setting of 160, a detector sensitivity of 6, and mean mass range of 30 kDa. Seventeen protein peaks shown significant differences between two groups were chosen to make a protein biomarker pattern. The decision tree which gives the highest discrimination included four peaks at 5,919, 8,583, 10,286, and 13,758 as splitters. The sensitivity and the specificity for classification of with the decision tree giving the highest discrimination were 96.7% (58/60) and 97.5% (39/40), respectively. When the protein biomarker pattern was tested with the blinded test set including 30 gastric cancer patients and 20 healthy individuals and, it yielded a sensitivity of 93.3% (28/30) and a specificity of 90% (18/20). Conclusions: These results suggest that serum-protein profiling pattern by SELDI system may distinguish gastric cancer patients from normal counterparts with relatively high sensitivity and specificity. No significant financial relationships to disclose.

The detected number of early gastric cancer has been markedly increasing due to the progress in various diagnostic method, including double contrast radiography, conventional and electronic endoscopy with biopsy. Dye- spraying method has enabled the exact definition of lateral extension of cancer, and the advent of endoscopic ultrasound has made it possible to accurately estimate its invasive depth. In addition, the establishment of the mass screening system has contributed to the detection of gastric cancer with favorable prognosis. To determine whether the recent advances in early detection and treatment of gastric cancer are effective, and contribute to change the cumulative 5-year-survival rate we retrospectively studied a consecutive number of patients with gastric cancer who underwent surgery at the Cancer Institute Hospital. We correlated the endoscopic resection and surgery. In recent years early cancer has accounted for approximately 45% – 50% of the total of 350 to 400 patients with gastric cancer who were treated annually at our institution. Endoscopic resection can be applied to about 28% of early cancer limited to the mucosal membrane. Similarly, the preoperative staging of cancer has been made possible by the progress in the integrated diagnostic imaging, and appropriate operation method can be selected according to its stage estimated.. The operation method has also been improved in the terms of reductive, standard, and extended surgery. However, the chronological changes of cancer staging and treatment method have been brought about in most part by the progress in the methodology of the diagnosis The limit of surgical treatment was noted in terms of extended radical surgery and adjuvant chemotherapy. Efforts should be directed to the detection of early cancer which can be radically treated by reductive and function preserving surgery or by endoscopic resection.

Systematic alphanumeric-coded endoscopy versus chromoendoscopy for the detection of precancerous gastric lesions and early gastric cancer in subjects at average risk for gastric cancer.

Appropriate interval of surveillance endoscopy for early detection of gastric cancer.

The key to reducing the mortality of gastric cancer is early detection, early diagnosis, and early treatment of gastric cancer. Early diagnosis of gastric cancer is the key to early detection and diagnosis of gastric cancer. Early diagnosis and treatment of gastric cancer is of great significance for improving the curative effect and reducing mortality of gastric cancer. The purpose of this paper is to study the diagnosis of early gastric cancer based on medical imaging techniques and mathematical modeling. The effect of W-DeepLab network-assisted diagnosis of images under white light was analyzed, and the value of Narrow Band Imaging and Blue Laser Imaging in the diagnosis of early gastric cancer was compared. Because Blue Laser Imaging endoscopy can clearly observe the demarcation line and microvascular morphology; but when using Narrow Band Imaging observation, part of the demarcation line and microvascular morphology is not observed. The results show that Blue Laser Imaging is brighter than Narrow Band Imaging's endoscopic images, and it is easier to observe the microstructure of lesions under endoscopy, so as to accurately determine the nature of lesions.

P-0067 Screening and Triage test for Early Detection of Gastric Cancer (STEAD-GC)