The most common digestive system (DS) cancers, including tumors of the gastrointestinal tract (GIT) such as colorectal cancer (CRC), gastric cancer (GC) and esophageal cancer (EC) as well as tumors of DS accessory organs such as pancreatic and liver cancer, are responsible for more than one-third of all cancer-related deaths worldwide, despite the progress that has been achieved in anticancer therapy. Due to these limitations in treatment strategies, oncological research has taken outstanding steps towards a better understanding of cancer cell biological complexity and heterogeneity. These studies led to new molecular target-driven therapeutic approaches. Different in vivo and in vitro studies have revealed significant expression of B7 homologue 3 (B7-H3) among the most common cancers of the GIT, including CRC, GC, and EC, whereas B7-H3 expression in normal healthy tissue of these organs was shown to be absent or minimal. This molecule is able to influence the biological behavior of GIT tumors through the various immunological and nonimmunological molecular mechanisms, and some of them are shown to be the result of B7-H3-related induction of signal transduction pathways, such as Janus kinase 2/signal transducer and activator of transcription 3, phosphatidylinositol 3-kinase/protein kinase B, extracellular signal-regulated kinase, and nuclear factor-κB. B7-H3 exerts an important role in progression, metastasis and resistance to anticancer therapy in these tumors. In addition, the results of many studies suggest that B7-H3 stimulates immune evasion in GIT tumors by suppressing antitumor immune response. Accordingly, it was observed that experimental depletion or inhibition of B7-H3 in gastrointestinal cancers improved antitumor immune response, impaired tumor progression, invasion, angiogenesis, and metastasis and decreased resistance to anticancer therapy. Finally, the high expression of B7-H3 in most common cancers of the GIT was shown to be associated with poor prognosis. In this review, we summarize the established data from different GIT cancer-related studies and suggest that the B7-H3 molecule could be a promising prognostic biomarker and therapeutic target for anticancer immunotherapy in these tumors.

Background: A pyogenic liver abscess (PLA) represents a pus-filled cavity within the liver parenchyma caused by the invasion and multiplication of bacteria. The most common offender isolated from the PLA in children is Staphylococcus aureus. Abiotrophia defectiva is a Gram-positive pleomorphic bacterium, commonly found in the oral cavity, intestinal, and genitourinary mucosa as part of the normal microbiota. It has been proven to be an etiological factor in various infections, but rarely in cases of PLA. The case presented here is, to the best of our knowledge, the first pediatric case of PLA caused by A. defectiva. Case presentation: A 13-year-old Caucasian boy presented with a two-day history of abdominal pain, fever up to 40°C, and polyuria. Contrast-enhanced computed tomography (CT) scan revealed a single, multiloculated liver lesion, suggestive of a liver abscess. The boy had sustained a bicycle handlebar injury to his upper abdomen 3 weeks before the symptoms appeared and had been completely asymptomatic until 2 days before admission. He was successfully treated with antibiotic therapy and open surgical drainage. A. defectiva was isolated from the abscess material. Histopathology report described the lesion as a chronic PLA. Conclusions: A. defectiva is a highly uncommon cause of liver abscess in children. In such cases, various predisposing factors should be considered, including antecedent blunt abdominal trauma.

Recent scientific data recognize the B7-H3 checkpoint molecule as a potential target for immunotherapy of pediatric solid tumors (PSTs). B7-H3 is highly expressed in extracranial PSTs such as neuroblastoma, rhabdomyosarcoma, nephroblastoma, osteosarcoma, and Ewing sarcoma, whereas its expression is absent or very low in normal tissues and organs. The influence of B7-H3 on the biological behavior of malignant solid neoplasms of childhood is expressed through different molecular mechanisms, including stimulation of immune evasion and tumor invasion, and cell-cycle disruption. It has been shown that B7-H3 knockdown decreased tumor cell proliferation and migration, suppressed tumor growth, and enhanced anti-tumor immune response in some pediatric solid cancers. Antibody-drug conjugates targeting B7-H3 exhibited profound anti-tumor effects against preclinical models of pediatric solid malignancies. Moreover, B7-H3-targeting chimeric antigen receptor (CAR)-T cells demonstrated significant in vivo activity against different xenograft models of neuroblastoma, Ewing sarcoma, and osteosarcoma. Finally, clinical studies demonstrated the potent anti-tumor activity of B7-H3-targeting antibody-radioimmunoconjugates in metastatic neuroblastoma. This review summarizes the established data from various PST-related studies, including in vitro, in vivo, and clinical research, and explains all the benefits and potential obstacles of targeting B7-H3 by novel immunotherapeutic agents designed to treat malignant extracranial solid tumors of childhood.

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Introduction. Annular pancreas is a rare congenital anomaly in which a band of pancreatic tissue, in continuity with pancreatic head, completely or incompletely surrounds the descending part of duodenum. An abnormal pancreatic development can cause complete annular pancreas, partial annular pancreas and pancreas divisum. Complete annular pancreas is diagnosed in newborns, while the diagnosis of partial annular pancreas is more frequently established in adults. The most reliable diagnostic methods are computed tomography and magnetic resonance cholangiopancreatography. The anomaly is treated surgically, using bypass procedures. Case report. A 12-year-old girl presented malnourished, with occasional feeding problems, vomiting, heartburn and pain from infancy. Upper gastrointestinal series showed extremely dilated stomach, the first and the second part of the duodenum. Endoscopic exam revealed the dilated stomach, pilorus, the first and the second part of the duodenum with retained contrast, while the entrance of the endoscope into the third part of duodenum was not possible. Computed tomography showed pancreatic tissue encircling the second part of duodenum and the characteristic "crocodile jaw" sign. Roux-en-Y duodeno-jejunostomy was performed as a bypass procedure. Conclusion. Complete annular pancreas is a well known and easily diagnosed anomaly in newborns. Partial annular pancreas is often poorly recognized, especially in patients who do not present with marked duodenal obstruction. Unrevealed, it causes chronic problems in food intake, with possible serious complications. Although very rare condition in pediatric population, partial annular pancreas should be taken into consideration in unclear cases of chronic poor oral food intake and vomiting.