Spatial modelling of tumour drug resistance: the case of GIST liver metastases.

This work is devoted to modelling gastrointestinal stromal tumour metastases to the liver, their growth and resistance to therapies. More precisely, resistance to two standard treatments based on tyrosine kinase inhibitors (imatinib and sunitinib) is observed clinically. Using observations from medical images (CT scans), we build a spatial model consisting in a set of non-linear partial differential equations. After calibration of its parameters with clinical data, this model reproduces qualitatively and quantitatively the spatial tumour evolution of one specific patient. Important features of the growth such as the appearance of spatial heterogeneities and the therapeutical failures may be explained by our model. We then investigate numerically the possibility of optimizing the treatment in terms of progression-free survival time and minimum tumour size reachable by varying the dose of the first treatment. We find that according to our model, the progression-free survival time reaches a plateau with respect to this dose. We also demonstrate numerically that the spatial structure of the tumour may provide much more insights on the cancer cell activities than the standard RECIST criteria, which only consists in the measurement of the tumour diameter. Finally, we discuss on the non-predictivity of the model using only CT scans, in the sense that the early behaviour of the lesion is not sufficient to predict the response to the treatment.

Disorder of Endothelia Vessels' Functional State with Malignant Tumors in Patients Exposed Anthropogenic Radiation.

The aim of this research is to determine the characteristics of endothelial factors and the hemostatic system conditions with malignant neoplasms patients, which were exposed to ionizing radiation. Total number of examined people is 223, 153 of them are patients with gastrointestinal tract oncopathology. The article presents the results of the analysis of numerical indicators of endothelial condition and platelet hemostasis of patients, who had cancer. They lived in the regions of Kazakhstan, subjected to contamination of radionuclides as a result of nuclear weapons tests, which took place in this region from 1949 to 1989. These results then were compared to cancer patients and healthy individuals with no radiation risk. The study revealed the presence of higher levels of endothelial dysfunction and following trigger of the hemostatic system in patients with malignant tumors of the gastrointestinal tract. In particular, the defined high degree of endothelial dysfunction include endothelium- dependent vasodilation, content desquamated endothelial cells in peripheral blood and von Willebrand factor. These indicators have a clear correlation with the degree of disorder of studied parameters of the hemostasis, which can cause the development of thrombotic complications.

The coming of ramucirumab in the landscape of anti-angiogenic drugs: potential clinical and translational perspectives.

INTRODUCTION: Angiogenesis plays a pivotal role in the development and progression of tumors and it represents a crucial target for therapeutic strategies. Until now, regulatory agencies approved antiangiogenic agents targeting the VEGF and multi-target agents carrying antiangiogenic and anti-proliferative effects. They often provide only a modest survival benefit and their role in clinical practice is debated. The limited efficacy may be partially explained by the complexity of the molecular background of angiogenic processes, composed of several pathways interacting with both tumor cells and the microenvironment. AREAS COVERED: Ramucirumab is a fully human monoclonal antibody selectively binding and inhibiting the VEGF receptor 2 (VEGFR-2), a crucial molecule involved in angiogenesis. A series of Phase I-II trials conducted in a wide spectrum of malignancies reported promising antitumor activity. In 2014, data from large Phase III clinical trials in gastrointestinal, lung and breast malignancies were released. EXPERT OPINION: Considering the evidences of efficacy emerging from the available Phase III trials, the antiangiogenic approach emerged as a promising strategy particularly for the treatment of gastric cancer. Nevertheless, the identification and validation of potentially predictive biomarkers are necessary to improve the selection of patients and the globally awaited clinical benefit.

Prognostic angiogenic markers (endoglin, VEGF, CD31) and tumor cell proliferation (Ki67) for gastrointestinal stromal tumors.

AIM: To evaluate the correlation between the immunoexpression of angiogenic markers [CD31, CD105 and vascular endothelial growth factor (VEGF)], proliferative index (Ki67), and prognosis of patients with gastrointestinal stromal tumors (GIST). METHODS: This is a retrospective study of 54 GIST cases. Medical records were searched to obtain the GIST patients' demographic and clinical data, and paraffin-embedded blocks of tumor samples were retrieved from the hospital archives to conduct a new immunohistochemical evaluation. The tumor samples of GIST patients were subject to immunohistochemical evaluation for endoglin (CD105), CD31, VEGF, and Ki67 expression. The CD105 and CD31 intratumoral microvascular density (IMVD) was measured using automated analysis. We determined the correlation between the immunoexpression of CD105, CD31, VEGF, Ki67 and prognosis. In addition, we conducted a cutoff analysis using the receiver-operating characteristic curve. VEGF positivity was classified as either null/weak or strong. Ki67 was evaluated using a cutoff of 5% positive cells. The prognosis was classified as good (patient alive without recurrence) or poor (patient with recurrence/death). RESULTS: The distribution of tumor sites among the 54 analyzed samples was as follows: 27 (50%) in the stomach, 20 (37.1%) in the small intestine, 6 (11.1%) in the colon, and 1 (1.8%) in the esophagus. The size of the tumors ranged from 2 to 33 cm (median: 8 cm); in 12 cases (22.2%), the tumor was below 5 cm at the largest diameter, but in 42 cases (77.7%), the tumor was larger than 5 cm. The means of CD105 and CD31 were significantly higher in the group with poor prognosis (P < 0.001). The cut-off values of CD105 (> 1.2%) and CD31 (> 2.5%) in the receiver-operating characteristic curve were related to a poorer prognosis. Cases with a better prognosis showed significantly null/weak staining for VEGF (P < 0.001). Ki-67 expression of ≥ 5% was strongly correlated with a worse prognosis (P < 0.001). In the multivariate analysis, CD105 was the variable that most strongly correlated with prognosis. CONCLUSION: The IMVD cutoff values for the angiogenic markers CD105 and CD31, may be prognostic factors for GIST, in addition to VEGF and Ki67.

Quantitative study on appearance of microvessels in spectral endoscopic imaging.

Increase in abnormal microvessels in the superficial mucosa is often relevant to diagnostic findings of neoplasia in digestive endoscopy; hence, observation of superficial vasculature is crucial for cancer diagnosis. To enhance the appearance of such vessels, several spectral endoscopic imaging techniques have been developed, such as narrow-band imaging and blue laser imaging. Both techniques exploit narrow-band blue light for the enhancement. The emergence of such spectral imaging techniques has increased the importance of understanding the relation of the light wavelength to the appearance of superficial vasculature, and thus a new method is desired for quantitative analysis of vessel visibility in relation to the actual structure in the tissue. Here, we developed microvessel-simulating phantoms that allowed quantitative evaluation of the appearance of 15-µm-thick vessels. We investigated the relation between the vascular contrast and light wavelength by the phantom measurements and also verified it in experiments with swine, where the endoscopically observed vascular contrast was investigated together with its real vascular depth and diameter obtained by microscopic observation of fluorescence-labeled vessels. Our study indicates that changing the spectral property even in the wavelength range of blue light may allow selective enhancement of the vascular depth for clinical use.

Targeted therapy in sarcomas other than GIST tumors.

Non-GIST soft tissue sarcomas are a heterogeneous grouping of mesenchymal tumors that comprise less than 1% of adult malignancies. Treatment continues to be based on cytotoxic chemotherapy regimens. However, characterization of the molecular pathway deregulations that drive these tumors has led to the emergence of more customized treatment options. In this review, we focus on the multitude of molecular inhibitors targeting angiogenesis and cell cycle pathways being tested in clinical trials.

Contrast-enhanced endoscopic ultrasonography can predict a higher malignant potential of gastrointestinal stromal tumors by visualizing large newly formed vessels.

BACKGROUND: The aim of this study was to elucidate the histologic and clinical implications of detection of intratumoral vessels on contrast-enhanced endoscopic ultrasonography (CE-EUS) in gastrointestinal stromal tumors (GISTs). METHODS: Thirteen patients with a GIST, all of whom were referred for surgery, underwent presurgical CE-EUS. The malignant potential, assessed according to the modified Fletcher risk classification system, and the histologic degree of angiogenesis were compared with the presence or absence of intratumoral vessels on CE-EUS. RESULTS: Of the six tumors with intratumoral vessels observed on CE-EUS, five were intermediate- or high-risk GISTs, and the remaining seven negative cases were categorized as very low risk or low risk. The presence of intratumoral vessels on CE-EUS was significantly correlated with a higher-risk classification (p = 0.005). On histologic examination, all GISTs having visualized vessels incorporated vessels of more than 500 µm in diameter. The large intratumoral vessels of the five intermediate- or high-risk GISTs lacked elastic fibers, suggesting that they were neovascular in nature. These higher-risk tumors were also found, by immunohistochemical analysis, to have high expression of vascular endothelial growth factor. CONCLUSIONS: Intratumoral vessels observed in GISTs on CE-EUS are correlated with a higher degree of angiogenesis, resulting in higher malignant potential.

Anti-angiogenic therapy, a new player in the field of sarcoma treatment.

Sarcomas encompass a heterogeneous family of mesenchymal malignancies. In metastatic disease improvement in outcome has been limited and there is a clear need for the development of new therapies. One potential target is angiogenesis, already an accepted target for treatment of more prevalent cancers. Multiple (pre)clinical studies focused on the role of angiogenesis and anti-angiogenic treatment in sarcomas. However, getting significant results is complicated due to the relatively small number of patients and the broad range of sarcoma subtypes. Recently, pazopanib has been approved for the treatment of advanced soft tissue sarcoma patients, which is an important step forward and paves the way for the introduction of anti-angiogenic treatment in sarcomas. However, more studies are needed to understand the biological mechanisms by which patients respond to angiogenic inhibitors and to detect markers of response. This review covers the knowledge that has been gained on the role of angiogenesis and anti-angiogenic therapy in sarcomas.

New vascular disrupting agents in upper gastrointestinal malignancies.

Antivascular approaches aim to cause rapid and catastrophic shutdown in the vascular function of the tumour, leading to extensive tumour cell death. Tumour vascular disrupting agents (VDAs) are a new class of cancer therapies that target the existing vasculature of tumours, taking advantage of the relative instability of tumour vasculature and its supporting structures. Treatment with VDAs induces a rapid collapse and regression of tumour vessels, with a consequent deprivation of blood and oxygen which leads to ischemic or hemorrhagic necrosis of the tumour. In this review, an overview of the most recently developed vascular disrupting agents is reported, focusing on the biological effects exerted by these compounds on endothelial cells and tumour vasculature, potentially effective in the treatment of several malignancies including upper gastrointestinal tumours. In particular, we have focused on the antimitotic agent combretastatin and its numerous synthetic analogues such as combretastatin A-4-phosphate, OXI4503, and AVE8062, and on the colchicine analogue ZD6126.

An expression signature of the angiogenic response in gastrointestinal neuroendocrine tumours: correlation with tumour phenotype and survival outcomes.

BACKGROUND: Gastroenteropancreatic neuroendocrine tumours (GEP-NETs) are heterogeneous with respect to biological behaviour and prognosis. As angiogenesis is a renowned pathogenic hallmark as well as a therapeutic target, we aimed to investigate the prognostic and clinico-pathological role of tissue markers of hypoxia and angiogenesis in GEP-NETs. METHODS: Tissue microarray (TMA) blocks were constructed with 86 tumours diagnosed from 1988 to 2010. Tissue microarray sections were immunostained for hypoxia inducible factor 1α (Hif-1α), vascular endothelial growth factor-A (VEGF-A), carbonic anhydrase IX (Ca-IX) and somatostatin receptors (SSTR) 1-5, Ki-67 and CD31. Biomarker expression was correlated with clinico-pathological variables and tested for survival prediction using Kaplan-Meier and Cox regression methods. RESULTS: Eighty-six consecutive cases were included: 51% male, median age 51 (range 16-82), 68% presenting with a pancreatic primary, 95% well differentiated, 51% metastatic. Higher grading (P=0.03), advanced stage (P<0.001), high Hif-1α and low SSTR-2 expression (P=0.03) predicted for shorter overall survival (OS) on univariate analyses. Stage, SSTR-2 and Hif-1α expression were confirmed as multivariate predictors of OS. Median OS for patients with SSTR-2+/Hif-1α-tumours was not reached after median follow up of 8.8 years, whereas SSTR-2-/Hif-1α+ GEP-NETs had a median survival of only 4.2 years (P=0.006). CONCLUSION: We have identified a coherent expression signature by immunohistochemistry that can be used for patient stratification and to optimise treatment decisions in GEP-NETs independently from stage and grading. Tumours with preserved SSTR-2 and low Hif-1α expression have an indolent phenotype and may be offered less aggressive management and less stringent follow up.

[Angiogenesis and vascular endothelial growth factor, role in the pathology of the gastrointestinal tract].

A review of the literature, the authors present information about angiogenesis, as the process of formation of new blood vessels in the organ or tissue from pre-existing vasculature by migration and proliferation of endothelial cells, as well as on the processes of regulation. Presents key regulatory system angiogenesis. The main attention is paid Vascular endothelial growth factor (VEGF). Specially structured data on the role of Vascular endothelial growth factor in human pathology, including diseases of gastrointestinal tract, inflammatory and neoplastic nature.

The benefit of using CT-perfusion imaging for reliable response monitoring in patients with gastrointestinal stromal tumor (GIST) undergoing treatment with novel targeted agents.

Solely size-based response criteria may be unreliable in patients with gastrointestinal stromal tumors (GIST) treated with tyrosine kinase inhibitors, because they typically underestimate responses to treatment. As GISTs are generally hypervascularized and novel targeted drugs knowingly affect angiogenic signaling pathways, perfusion measurements are expected to deliver important information about their efficacy. This pictorial essay illustrates the benefit of using complementary CT-perfusion-based measurements for more accurate evaluation of response to therapy in GIST.

Early outcomes of empiric embolization of tumor-related gastrointestinal hemorrhage in patients with advanced malignancy.

PURPOSE: To report short-term results of empiric transcatheter embolization for patients with advanced malignancy and gastrointestinal (GI) hemorrhage directly from a tumor invading the GI tract wall. MATERIALS AND METHODS: Between 2005 and 2011, 37 mesenteric angiograms were obtained in 26 patients with advanced malignancy (20 men, six women; mean age, 56.2 y) with endoscopically confirmed symptomatic GI hemorrhage from a tumor invading the GI tract wall. Angiographic findings and clinical outcomes were retrospectively evaluated. Clinical success was defined as absence of signs and symptoms of hemorrhage for at least 30 day following embolization. RESULTS: Active extravasation was demonstrated in three cases. Angiographic abnormalities related to a GI tract tumor were identified on 35 of 37 angiograms, including tumor neovascularity (n = 21), tumor enhancement (n = 24), and luminal irregularity (n = 5). In the absence of active extravasation, empiric embolization with particles and/or coils was performed in 25 procedures. Cessation of hemorrhage (ie, clinical success) occurred more frequently when empiric embolization was performed (17 of 25 procedures; 68%) than when embolization was not performed (two of nine; 22%; P = .03). Empiric embolization resulted in clinical success in 10 of 11 patients with acute GI bleeding (91%), compared with seven of 14 patients (50%) with chronic GI bleeding (P = .04). No ischemic complications were encountered. CONCLUSIONS: In patients with advanced malignancy, in the absence of active extravasation, empiric transcatheter arterial embolization for treatment of GI hemorrhage from a direct tumor source demonstrated a 68% short-term success rate, without any ischemic complications.

New targeted agents in gastroenteropancreatic neuroendocrine tumors.

Neuroendocrine carcinomas are rare neoplasms although of increasing incidence and concern. While traditionally considered of indolent nature, once they progress beyond surgical resectability, the outcome is ultimately fatal for the majority of patients. Somatostatin analogs are useful to control symptoms in functioning tumors and may slow tumor progression in certain disease settings, but sensitivity to conventional cytotoxic chemotherapy is rather limited. In this context, results of the recently published randomized trials with sunitinib and everolimus have demonstrated for the first time that there are agents able to positively impact on the natural history of this complex disease. In this review, we will discuss available data on angiogenesis and mammalian target of rapamycin inhibitors for the treatment of advanced well-differentiated gastroenteropancreatic neuroendocrine tumors.

[Surgical treatment for gastrointestinal stromal tumors].

The results of treatment of 15 patients with GIST tumors from 2007 to 2010. We describe the clinical manifestations depending on the location and development of complications. Estimated the complexity and accuracy of preoperative diagnosis using different instrumental technigues in accordance with the recommendations of an international agreement in 2005. Accurate diagnosis can be established only by using immunohistochemical study,which is true in all cases the presence of GIST tumors. As an additional method of imaging for suspected tumor site in the small intestine is used angiography of visceral abdominal arteries.

Novel molecular targets for the treatment of gastroenteropancreatic endocrine tumors: answers and unsolved problems.

As more knowledge on molecular alterations favoring carcinogenesis and spreading of gastroenteropancreatic endocrine tumors has become available, a number of targeted agents interfering with key growth and angiogenic pathways have been explored in preclinical and clinical studies. The mTOR inhibitor Everolimus, and the multi-target antiangiogenetic agent Sunitinib, have been shown to be effective and thus have been approved by the FDA for treatment of pancreatic endocrine tumors. However, there is little data on the primary resistance to targeted agents on these tumors. The goals of the present review are to elucidate the possible advantage of combined treatments in overcoming induced resistances, and to identify biomarkers able to predict clinical efficacy. Moreover, the role of interesting targets for which a strong biological rationale exists, and specific inhibitors are available, such as the Src Family Kinases and the Hedgehog Pathway, are discussed. There is now need for more preclinical studies on cell lines and animal models to provide a stronger preclinical background in this field, as well as clinical trials specifically comparing one targeted therapy with another or combining different targeted agents.

Phase II trial of erlotinib and bevacizumab in patients with advanced upper gastrointestinal cancers.

BACKGROUND: Patients with upper gastrointestinal cancers have a poor prognosis and only few treatment options. The epidermal growth factor receptor (EGFR) and vascular endothelial growth factor (VEGF) are valid targets in many solid tumours, and they have synergistic effects in preclinical studies. METHODS: In this multi-center phase II trial patients with chemoresistant, metastatic upper gastrointestinal cancer were treated with erlotinib (150 mg daily) and bevacizumab (10 mg/kg every two weeks). Primary endpoint was overall response rate (ORR). Secondary endpoints were progression free survival (PFS), overall survival (OS), toxicity and biomarker correlates. Plasma samples were analysed for EGFR and angiogenesis related markers using quantitative immunoassays. RESULTS: One hundred and two patients were enrolled in the trial between June 2006 and October 2007. The most common toxicities were skin reaction, diarrhoea, and fatigue. ORR was 6%, median PFS was 2.2 months, and OS 4.3 months. Low concentration of urokinase plasminogen activator receptor (uPAR) domain I was correlated to longer PFS and OS. DISCUSSION: The combination of erlotinib and bevacizumab is well tolerated, however, with low clinical activity in patients with chemoresistant UGI cancer. Some patients do benefit from the therapy, and uPAR forms are potential biomarkers in these patients.

Novel therapeutic agents for the treatment of gastroenteropancreatic neuroendocrine tumors.

Neuroendocrine tumors (NET) are frequently diagnosed late and not amenable to curative surgery due to metastatic disease to the liver and lymph nodes. The disease is complex and heterogeneous given the various functionalities, distinct tumor growth patterns, and tumor spread upon diagnosis. Established therapies include somatostatin analogues, alpha-interferon, systemic chemotherapy, and loco-regional therapies of the liver. The availability of novel agents and expression of targets, such as growth factor receptors, different subtypes of somatostatin receptors, and the mammalian target of rapamycin (mTOR) have led to the exploration of different classes of drugs and offer new treatment opportunities in neuroendocrine tumors. This review provides an overview on novel drugs, focus on the impact of recently approved drugs on the management of NET disease, and outline future perspectives.

Percutaneous ultrasonography-guided core needle biopsy of gastrointestinal lesions: what's its actual role in clinical practice? A retrospective study for safety and effectiveness.

PURPOSE: Endoscopic biopsy is commonly performed to obtain a pathological diagnosis of gastrointestinal (GI) lesions. When the lesions are submucosal, subserosal, or exophytic, endoscopic biopsy is often unsuccessful, and endoscopic ultrasound (EUS)-guided biopsy is considered the procedure of choice in these cases. Nevertheless, in some patients both endoscopic and EUS-guided biopsy are not indicated, or yield inconclusive cyto-histological results. The aim of this study was to assess the efficacy and safety of percutaneous ultrasonography (US)-guided biopsy of GI wall lesions, and to define its actual role in clinical practice. MATERIALS AND METHODS: A retrospective study was conducted on 45 consecutive US-guided biopsies of GI lesions. All biopsies were performed in patients unsuitable for endoscopic or EUS-guided biopsy, or with lesions inaccessible to endoscopic techniques, or with inconclusive results from endoscopic or EUS-guided biopsy. Biopsies were performed with an 18 or 20-gauge Tru-cut needle under US guidance. Biopsy results were compared with the final diagnosis that was based on surgical pathological findings or clinical instrumental follow-up of at least 20 months. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), overall accuracy, and complication rate of the procedure were calculated. RESULTS: One biopsy specimen (2.2 %) was inadequate for cyto-histologic examination. In the remaining 44 cases, US-guided biopsy correctly identified 39 / 40 (97.5 %) malignant lesions, and 4 / 4 (100 %) benign lesions. One case resulted in a false negative (2.2 %). The sensitivity, specificity, PPV, NPV, and overall diagnostic accuracy were 97.5 %, 100 %, 100 %, 80 % and 97.7 %, respectively. Including also the inadequate specimen into the analysis, they were 95.1 %, 100 %, 100 %, 66.7 % and 95.6 %, respectively. No procedure-related complications were observed. In ten cases (22.2 %), US-guided biopsy results made it possible to avoid unnecessary surgical exploration. CONCLUSION: Percutaneous US-guided core biopsy of GI wall lesions is an accurate and safe technique that makes it possible in select cases to obtain a correct pathological diagnosis and prevent unnecessary surgical exploration. Although it has been replaced by EUS-guided biopsy as the procedure of choice to sample submucosal or subserosal GI lesions, US-guided biopsy can still play a useful role in the diagnostic workup of GI lesions when endoscopy or EUS is unsuccessful for various reasons or yields inconclusive cyto-histological results.