Metachronous lesions after gastric endoscopic submucosal dissection: first assessment of the FAMISH prediction score.

BACKGROUND: Surveillance after gastric endoscopic submucosal dissection (ESD) is recommended for all patients owing to the persistent risk of metachronous gastric lesions (MGLs). We developed and validated a prediction score to estimate MGL risk after ESD for early neoplastic gastric lesions, to define an individualized and cost-saving approach. METHODS: Clinical predictors and a risk score were derived from meta-analysis data. A retrospective, single-center, cohort study including patients with ≥ 3 years of standardized surveillance after ESD was conducted for score validation. Predictive accuracy of the score by the area under the receiver operating characteristic curve (AUC) was assessed and cumulative probabilities of MGL were estimated. RESULTS: The risk score (0-9 points) included six clinical predictors (scored 0-3): positive family history of gastric cancer, older age, male sex, corpus intestinal metaplasia, synchronous gastric lesions, and persistent Helicobacter pylori infection (FAMISH). The study population included 263 patients. The MGL rate was 16 %. The score diagnostic accuracy for predicting MGL at 3 years' follow-up, measured by the AUC, was 0.704 (95 %CI 0.603-0.806). At 3 years and a cutoff < 2, the score achieved maximal sensitivity and negative predictive value; 15 % of patients could be assigned to a low-risk group, in which the progression to MGL was significantly lower than for the high-risk group (P = 0.04). CONCLUSION: The FAMISH score might be a useful tool to accurately identify patients with low-to-intermediate risk for MGL at 3 years of follow-up who could have surveillance intervals extended to reduce the burden of care.

Glycomic analysis of gastric carcinoma cells discloses glycans as modulators of RON receptor tyrosine kinase activation in cancer.

BACKGROUND: Terminal α2-3 and α2-6 sialylation of glycans precludes further chain elongation, leading to the biosynthesis of cancer relevant epitopes such as sialyl-Lewis X (SLe(X)). SLe(X) overexpression is associated with tumor aggressive phenotype and patients' poor prognosis. METHODS: MKN45 gastric carcinoma cells transfected with the sialyltransferase ST3GAL4 were established as a model overexpressing sialylated terminal glycans. We have evaluated at the structural level the glycome and the sialoproteome of this gastric cancer cell line applying liquid chromatography and mass spectrometry. We further validated an identified target expression by proximity ligation assay in gastric tumors. RESULTS: Our results showed that ST3GAL4 overexpression leads to several glycosylation alterations, including reduced O-glycan extension and decreased bisected and increased branched N-glycans. A shift from α2-6 towards α2-3 linked sialylated N-glycans was also observed. Sialoproteomic analysis further identified 47 proteins with significantly increased sialylated N-glycans. These included integrins, insulin receptor, carcinoembryonic antigens and RON receptor tyrosine kinase, which are proteins known to be key players in malignancy. Further analysis of RON confirmed its modification with SLe(X) and the concomitant activation. SLe(X) and RON co-expression was validated in gastric tumors. CONCLUSION: The overexpression of ST3GAL4 interferes with the overall glycophenotype of cancer cells affecting a multitude of key proteins involved in malignancy. Aberrant glycosylation of the RON receptor was shown as an alternative mechanism of oncogenic activation. GENERAL SIGNIFICANCE: This study provides novel targets and points to an integrative tumor glycomic/proteomic-profiling for gastric cancer patients' stratification. This article is part of a Special Issue entitled "Glycans in personalised medicine" Guest Editor: Professor Gordan Lauc.

Probing the O-glycoproteome of gastric cancer cell lines for biomarker discovery.

Circulating O-glycoproteins shed from cancer cells represent important serum biomarkers for diagnostic and prognostic purposes. We have recently shown that selective detection of cancer-associated aberrant glycoforms of circulating O-glycoprotein biomarkers can increase specificity of cancer biomarker assays. However, the current knowledge of secreted and circulating O-glycoproteins is limited. Here, we used the COSMC KO "SimpleCell" (SC) strategy to characterize the O-glycoproteome of two gastric cancer SimpleCell lines (AGS, MKN45) as well as a gastric cell line (KATO III) which naturally expresses at least partially truncated O-glycans. Overall, we identified 499 O-glycoproteins and 1236 O-glycosites in gastric cancer SimpleCells, and a total 47 O-glycoproteins and 73 O-glycosites in the KATO III cell line. We next modified the glycoproteomic strategy to apply it to pools of sera from gastric cancer and healthy individuals to identify circulating O-glycoproteins with the STn glycoform. We identified 37 O-glycoproteins in the pool of cancer sera, and only nine of these were also found in sera from healthy individuals. Two identified candidate O-glycoprotein biomarkers (CD44 and GalNAc-T5) circulating with the STn glycoform were further validated as being expressed in gastric cancer tissue. A proximity ligation assay was used to show that CD44 was expressed with the STn glycoform in gastric cancer tissues. The study provides a discovery strategy for aberrantly glycosylated O-glycoproteins and a set of O-glycoprotein candidates with biomarker potential in gastric cancer.

MSI phenotype and MMR alterations in familial and sporadic gastric cancer.

Microsatellite instability (MSI) is a major pathway involved in gastric carcinogenesis occurring in 20% of gastric cancer (GC). However, it is not clear whether MSI phenotype preferentially occurs in the sporadic or familial GC, when stringent inclusion criteria are used. The aim of this study was to compare the frequency of MSI and hypermethylation of MLH1 promoter in a large series of familial GC patients (non-HNPCC and non-CDH1-related) and sporadic cases. Additionally, we analysed the immunoexpression of MMR proteins in a fraction of cases. Overall, the frequency of familial GC was 7.1%, and the frequency of hereditary tumours was 4.6%. MSI phenotype and MLH1 hypermethylation frequencies were not statistical different between familial and sporadic GC settings. Further, the MSI phenotype was not associated with any clinico-pathological features studied in the familial GC setting, whereas in the sporadic setting, it was associated with older age, female gender and intestinal histotype. Using our stringent Amsterdam-based clinical criteria to select familial GC (number of cases, age of onset), we verified that sporadic and familial cases differed in gender but shared histopathological features. We verified that the frequency of MSI was similar in familial and sporadic GC settings, demonstrating that this molecular phenotype is not a hallmark of familial GC in contrast to what is verified in HNPCC. Moreover, we observed that the frequency of MLH1 hypermethylation is similar in sporadic and familial cases suggesting that in both settings MSI is not associated to MMR genetic alterations but in contrast to epigenetic deregulation.

The Extremely Rare Hypopharyngeal Fetal Rhabdomyoma in an Adult.

Extracardiac rhabdomyomas are rare benign tumors showing skeletal muscle differentiation. They can be divided into adult, fetal, and genital subtypes. Fetal rhabdomyomas are rarer than the adult subtype and although usually diagnosed at birth, the diagnosis is based on histology rather than patient age. We present a rare case of a 25-year-old man with a cellular fetal (juvenile) rhabdomyoma, found in the postcricoid region of the hypopharynx.