Managementofearlyasymptomaticgastrointestinalstromaltumorsofthe stomach

Gastrointestinal stromal tumors(GIST) are the most common mesenchymal tumors of the digestive tract. Approximately two thirds of clinically manifest tumors occur in the stomach, nearly one third in the small bowel, and the rest in the colorectal region with a few cas-es in the esophagus. GIST originate within the smooth muscle layer in the wall of the tubular gastrointestinal tract and grow mostly toward the serosa, far less often toward the mucosa. In the latter case, ulceration may develop and can cause gastrointestinal bleeding as the cardinal symptom. However, most GIST of the stomach are asymptomatic. They are increasingly detected incidentally as small intramural or submucosal tumors during endoscopy and particularly during endoscopic ultra-sound. Epidemiological and molecular genetic findings suggest that early asymptomatic GIST of the stomach(< 1 cm) show self-limiting tumorigenesis. Thus, early(< 1 cm) asymptomatic gastric GIST(synonym: micro-GIST) are found in 20%-30% of the elderly. The mostlyelderly people with early gastric GIST have an excellent GIST-specific prognosis. Patients with early GIST of the stomach can therefore be managed by endoscopic sur-veillance.

Controlled and reversible induction of differentiation and activation of adult human hepatocytes by a biphasic culture technique

AIM: Clinical application of human hepatocytes (HC) is hampered by the progressive loss of growth and differentiation in vitro. The object of the study was to evaluate the effect of a biphasic culture technique on expression and activation of growth factor receptors and differentiation of human adult HC.METHODS: Isolated HC were sequentially cultured in a hormone enriched differentiation medium (DM) containing nicotinamide, insulin, transferrin, selenium, and dexamethasone or activation medium (AM) containing hepatocyte growth factor (HGF), epidermal growth factor (EGF), andgranulocyte-macrophage colony-stimulating factor (GMCSF). Expression, distribution and activation of the HC receptors (MET and EGFR) and the pattern of characteristic cytokeratin (CK) filaments were measured by fluorometry, confocal microscopy and Western blotting.RESULTS: In the biphasic culture system, HC underwent repeated cycles of activation (characterized by expression and activation of growth factor receptors) and re-differentiation (illustrated by distribution of typical filaments CK-18 but low or absent expression of CK-19). In AM increased expression of MET and EGFR was associated with receptor translocation into the cytoplasm and induction of atypical CK-19. In DM low expression of MET and EGFR was localized on the cell membrane and CK-19 was reduced. Receptor phosphorylation required embedding of HC in collagen type Ⅰ gel.CONCLUSION: Control and reversible modulation of growth factor receptor activation of mature human HC can be accomplishedin vitro, when defined signals from the extracellular matrix and sequential growth stimuli are provided. The biphasic technique helps overcome dedifferentiation, which occurs during continuous stimulation by means of growth factors.

Development and validation of an artificial intelligence model for predicting post-transplant hepatocellular cancer recurrence

Dear Editor,In recent years,criteria based on the combinationof morphology and biology have been proposed forimproving the selection of hepatocellular cancer(HCC)patients waiting for liver transplantation(LT)[1,2].Since all the proposed models showed suboptimalresults in predicting the risk of postLT recurrence,aprediction model constructed using artificial intelligence(Al)could be an attractive way to surpass this limit[3,4].Therefore,the Time_Radiological-response_Alpha-fetoproteIN_Artificial-Intelligence(TRAIN-AI)modelwas developed,combining morphology and biology tumorvariables.