Gastric and oesophageal cancers (GOCs) are lethal cancers which metastasise early and recur frequently, even after definitive surgery. The urokinase plasminogen activator system (uPAS) is strongly implicated in the invasion and metastasis of many aggressive tumours including GOCs. Urokinase plasminogen activator (uPA) interaction with its receptor, urokinase plasminogen activator receptor (uPAR), leads to proteolytic activation of plasminogen to plasmin, a broad-spectrum protease which enables tumour cell invasion and dissemination to distant sites. uPA, uPAR and the plasminogen activator inhibitor type 1 (PAI-1) are overexpressed in some GOCs. Accumulating evidence points to a causal role of activated receptor tyrosine kinase pathways enhancing uPAS expression in GOCs. Expression of these components are associated with poorer clinicopathological features and patient survival. Stromal cells, including tumour-associated macrophages and myofibroblasts, also express the key uPAS proteins, supporting the argument of stromal involvement in GOC progression and adverse effect on patient survival. uPAS proteins can be detected on circulating leucocytes, circulating tumour cells and within the serum; all have the potential to be developed into circulating biomarkers of GOC. Herein, we review the experimental and clinical evidence supporting uPAS expression as clinical biomarker in GOC, with the goal of developing targeted therapeutics against the uPAS.

Background: Peptide receptor radionuclide therapy (PRRT) is an approved treatment modality for gastroenteropancreatic neuroendocrine tumours (GEP NETs), Although Phase III randomised clinical trial data is not available for NETs of other site of origin, in practice, PRRT is used more widely in clinical practice, based on its mechanism of targeting the somatostatin receptor. Use of PRRT for lung (bronchial) NET, specifically typical and atypical carcinoid (TC, AC), has been reported only in small retrospective case series. This multicentre study adds to the evidence regarding utility of PRRT for lung NETs. Materials and Methods: A retrospective chart review of patients with TC and AC who received 177 Lu-dotatate PRRT between January 2002 and June 2019 in six hospitals across Australia was undertaken. Data regarding demographics, efficacy and toxicity was evaluated at each site by the treating clinician. Results: Forty-eight patients (32 AC, 15 TC, 1 unclassified) received a median of four 177 Lu-dotatate treatments. There was a median of one prior line of systemic treatment (range: 0-3). The response rate to 177 Lu-dotatate was 33%, with a median overall survival of 49 months (range of 3-91), at a median follow up of 33 months. This compares favourably with GEP NET. Overall toxicity was recorded as modest. Conclusions: 177 Lu-dotatate PRRT in patients with lung NETs is used in real world practice, where it appears well-tolerated with some efficacy. Further evidence could be obtained through a global prospective clinical or registry trial.

Gastric carcinoma and gastro-oesophageal junction (GC/GEJ) carcinoma remain a significant global problem, with patients presenting with symptoms often found to have advanced or metastatic disease. Treatment options for these patients have broadened in recent years with new chemotherapy agents, agents targeting angiogenic pathways and the development of immune checkpoint inhibitors (ICIs). Most initial advances have occurred in the refractory setting, where it is important to balance treatment benefits versus toxicity and patient quality of life. In the first-line treatment of advanced/metastatic GC/GEJ, platinum- and fluoropyrimidine-based chemotherapy protocols remain the backbone of therapy (with or without HER2-targeted therapy), with the FOLFIRI regimen offering an alternative in patients deemed unsuitable for a platinum agent. Microsatellite instability-high or mismatch repair-deficient cancers have been shown to benefit most from ICIs. In unselected patients previously treated with doublet or triplet platinum- and fluoropyrimidine-based chemotherapy and second-line chemotherapy with irinotecan or taxanes have formed the backbone of therapy with or without the addition of the vascular endothelial growth factor receptor-2 inhibitor ramucirumab in addition to paclitaxel. Beyond this, efficacy has been demonstrated with oral trifluridine/tipiracil and with single-agent nivolumab, in selected refractory patients. In this review, we highlight the positive evidence from key trials that have led to our current practice algorithm, with particular focus on the refractory advanced disease setting, discussing the areas of active research and highlighting the factors, including biomarkers and the influence of ethnicity, that contribute to therapeutic decision-making.

Brain metastasis from gastroesophageal adenocarcinomas (GOCs) is a rare but a devastating diagnosis. Human epidermal growth factor receptor 2 (HER2) is a prognostic and predictive biomarker in GOCs. The association of HER2 with GOC brain metastasis is not known. We performed a retrospective analysis of patients with GOCs with known HER2 status between January 2015 and November 2021. HER2 was assessed on either the primary tumour or metastasis by immunohistochemistry or in situ hybridization. The diagnosis of brain metastasis was made on standard imaging techniques in patients with symptoms or signs. HER2 results were available for 201 patients, with 34 patients (16.9%) HER2 positive. A total of 12 patients developed symptomatic brain metastasis from GOCs, of which 7 (58.3%) were HER2 positive. The development of symptomatic brain metastasis was significantly higher in the HER2-positive GOCs (OR8.26, 95%CI 2.09–35.60; p = 0.0009). There was no significant association of HER2 status and overall survival in patients with brain metastasis. Although the rate of brain metastasis remains low in GOCs, the incidence of symptomatic brain metastasis was significantly higher in patients with HER2-positive tumours.

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