Cost-Effectiveness and the Economics of Genomic Testing and Molecularly Matched Therapies.

Cost-effectiveness analysis of precision oncology can help guide value-driven care. Next-generation sequencing is increasingly cost-efficient over single gene testing because diagnostic algorithms require multiple individual gene tests to determine biomarker status. Matched targeted therapy is often not cost-effective due to the high cost associated with drug treatment. However, genomic profiling can promote cost-effective care by identifying patients who are unlikely to benefit from therapy. Additional applications of genomic profiling such as universal testing for hereditary cancer syndromes and germline testing in patients with cancer may represent cost-effective approaches compared with traditional history-based diagnostic methods.

Tofacitinib Is Associated With Increased Risk of Postoperative Venous Thromboembolism in Patients With Ulcerative Colitis.

BACKGROUND: In 2019, the Food and Drug Administration issued a black box warning for increased risk of venous thromboembolism in patients with rheumatoid arthritis exposed to tofacitinib. There are limited data regarding postoperative venous thromboembolism risk in patients with ulcerative colitis exposed to tofacitinib. OBJECTIVE: To assess whether preoperative exposure to tofacitinib is associated with increased odds of postoperative venous thromboembolism. DESIGN: Retrospective review. SETTINGS: Tertiary academic medical center. PATIENTS: Consecutive patients exposed to tofacitinib within 4 weeks before total abdominal colectomy or total proctocolectomy, with or without ileostomy, from 2014 to 2021, matched 1:2 for tofacitinib exposure or no exposure. INTERVENTION: Tofacitinib exposure versus no exposure. MAIN OUTCOME MEASURES: Ninety-day postoperative venous thromboembolism rate. RESULTS: Forty-two patients with tofacitinib exposure and 84 case-matched patients without tofacitinib exposure underwent surgery for medically refractory ulcerative colitis. Nine (22.0%) tofacitinib-exposed patients and 7 (8.5%) unexposed patients were diagnosed with venous thromboembolism within 90 days of surgery. In univariate logistic regression, patients exposed to tofacitinib had 3.01 times increased odds of developing venous thromboembolism within 90 days after surgery compared to unexposed patients ( p = 0.04; 95% CI, 1.03-8.79). Other venous thromboembolism risk factors were not significantly associated with venous thromboembolisms. Venous thromboembolisms in both groups were most commonly portomesenteric vein thromboses (66.7% in the tofacitinib-exposed group and 42.9% in the unexposed group) and were diagnosed at a mean of 23.2 days (range, 3-90 days) postoperatively in the tofacitinib-exposed group and 7.9 days (1-19 days) in the unexposed group. There were no statistically significant differences in location or timing between the 2 groups. LIMITATIONS: Retrospective nature of the study and associated biases. Reliance on clinically diagnosed venous thromboembolisms may underreport the true incidence rate. CONCLUSIONS: Tofacitinib exposure before surgery for medically refractory ulcerative colitis is associated with 3 times increased odds of venous thromboembolism compared with patients without tofacitinib exposure. See Video Abstract . TOFACITINIB SE ASOCIA CON UN MAYOR RIESGO DE TROMBOEMBOLISMO VENOSO POSTOPERATORIO EN PACIENTES CON COLITIS ULCEROSA: ANTECEDENTES:En 2019, la FDA emitió una advertencia de recuadro negro sobre un mayor riesgo de tromboembolismo venoso en pacientes con artritis reumatoide expuestos a tofacitinib. Hay datos limitados sobre el riesgo de tromboembolismo venoso postoperatorio en pacientes con colitis ulcerosa expuestos a tofacitinib.OBJETIVO:Evaluar si la exposición preoperatoria a tofacitinib se asocia con mayores probabilidades de tromboembolismo venoso postoperatorio.DISEÑO:Revisión retrospectiva.LUGARES:Centro médico académico terciario.PACIENTES:Pacientes consecutivos expuestos a tofacitinib dentro de las 4 semanas previas a la colectomía abdominal total o proctocolectomía total, con o sin ileostomía, entre 2014 y 2021, emparejados 1:2 para exposición a tofacitinib o ninguna exposición.INTERVENCIÓN(S):Exposición a tofacitinib versus ninguna exposición.PRINCIPALES MEDIDAS DE RESULTADO:Tasa de tromboembolismo venoso posoperatorio a los 90 días.RESULTADOS:Cuarenta y dos pacientes con exposición a tofacitinib y 84 pacientes de casos similares sin exposición a tofacitinib se sometieron a cirugía por colitis ulcerosa médicamente refractaria. Nueve (22,0%) pacientes expuestos a tofacitinib y 7 (8,5%) pacientes no expuestos fueron diagnosticados con tromboembolismo venoso dentro de los 90 días posteriores a la cirugía. En la regresión logística univariada, los pacientes expuestos a tofacitinib tuvieron 3,01 veces más probabilidades de desarrollar un tromboembolismo venoso dentro de los 90 días posteriores a la cirugía en comparación con los no expuestos ( p = 0,04, IC del 95 %: 1,03-8,79). Otros factores de riesgo de tromboembolismo venoso no se asociaron significativamente con el tromboembolismo venoso. Los tromboembolismos venosos en ambos grupos fueron más comúnmente trombosis de la vena portomesentérica (66,7% en los expuestos a tofacitinib y 42,9% en los no expuestos) y se diagnosticaron en una media de 23,2 días (rango, 3-90 días) después de la operación en los expuestos a tofacitinib y 7,9 días. (1-19 días) en los grupos no expuestos, respectivamente. No hubo diferencias estadísticamente significativas en la ubicación o el momento entre los dos grupos.LIMITACIONES:Carácter retrospectivo del estudio y sesgos asociados. La dependencia de tromboembolismos venosos diagnosticados clínicamente puede subestimar la tasa de incidencia real.CONCLUSIONES:La exposición a tofacitinib antes de la cirugía para la colitis ulcerosa médicamente refractaria se asocia con probabilidades 3 veces mayores de tromboembolismo venoso en comparación con los pacientes sin exposición a tofacitinib. (Traducción-Dr. Mauricio Santamaria ).

Risk of Proctectomy After Ileorectal Anastomosis in Familial Adenomatous Polyposis in the Modern Era.

BACKGROUND: Prophylactic surgery for familial adenomatous polyposis has evolved over several decades. Restorative proctocolectomy with IPAA provides an alternative to total abdominal colectomy with ileorectal anastomosis. We have previously shown that the rate of proctectomy and rectal cancer after total abdominal colectomy with ileorectal anastomosis in the "pre-pouch era" was 32% and 13%, respectively. OBJECTIVE: To determine the rate of proctectomy and rectal cancer among familial adenomatous polyposis patients and relative rectal sparing (fewer than 20 rectal polyps) selected for total abdominal colectomy with ileorectal anastomosis in the modern era. DESIGN: Retrospective cohort study. SETTING: Single tertiary care institution with a hereditary colorectal cancer registry. PATIENTS: Patients with familial adenomatous polyposis who underwent total abdominal colectomy with ileorectal anastomosis between 1993 and 2020. MAIN OUTCOME MEASURES: Incidence of proctectomy for any indication and rectal cancer. RESULTS: A total of 197 patients with a median age of 24 years (range, 10-67) were included. The median follow-up after total abdominal colectomy with ileorectal anastomosis was 13 years (interquartile range, 6-17). Sixteen patients (8%) underwent proctectomy. Indications included rectal cancer in 6 patients (3%; 2 stage I and 4 stage III), polyps with high-grade dysplasia in 4 (2%), progressive polyp burden in 3 (1.5%), defecatory dysfunction in 2 (1%), and anastomotic leak in 1 (0.5%). Among 30 patients (18%) with 20 or more rectal polyps at the time of total abdominal colectomy with ileorectal anastomosis, 8 patients (26%) underwent proctectomy and 3 patients developed rectal cancer (10%). Among 134 patients (82%) with fewer than 20 polyps, 8 patients (6%) underwent proctectomy and 3 patients developed rectal cancer (2%). Number of rectal polyps at the time of total abdominal colectomy with ileorectal anastomosis was associated with the likelihood of proctectomy (OR 1.1, p < 0.001) but not incident rectal cancer ( p = 0.3). LIMITATION: Retrospective data collection. CONCLUSIONS: Patients with familial adenomatous polyposis selected for total abdominal colectomy with ileorectal anastomosis by rectal polyp number have low rates of proctectomy and rectal cancer compared to historical controls. With appropriate selection criteria and surveillance, total abdominal colectomy with ileorectal anastomosis remains an important and safe treatment option for patients with familial adenomatous polyposis. See Video Abstract . RIESGO DE PROCTECTOMA DESPUS DE ANASTOMOSIS ILEORRECTAL EN POLIPOSIS ADENOMATOSA FAMILIAR EN LA ERA MODERNA: ANTECEDENTES:La cirugía profiláctica para la poliposis adenomatosa familiar (PAF) ha evolucionado durante varias décadas. La proctocolectomía restauradora con anastomosis anal con bolsa ileal (IPAA) proporciona una alternativa a la colectomía abdominal total con anastomosis ileorrectal (TAC/IRA). Anteriormente hemos demostrado que la tasa de proctectomía y cáncer de recto después de TAC/IRA en la era "pre-bolsa" era del 32% y el 13%, respectivamente.OBJETIVO:Determinar la tasa de proctectomía y cáncer de recto entre pacientes con PAF y pacientes con preservación rectal relativa (<20 pólipos rectales) seleccionados para TAC/IRA en la era moderna.DISEÑO:Estudio de cohorte retrospectivo.ÁMBITO:Institución única de atención terciaria con un registro de cáncer colorrectal hereditario.PACIENTES:Pacientes con PAF que se sometieron a TAC/IRA entre 1993 y 2020.MEDIDAS DE RESULTADO PRINCIPALES:Incidencia de proctectomía por cualquier indicación y cáncer de recto.RESULTADOS:Se incluyeron 197 pacientes con una mediana de edad de 24 años (rango 10-67). La mediana de seguimiento tras TAC/IRA fue de 13 años (RIC 6-17). 16 pacientes (8%) fueron sometidos a proctectomía. Las indicaciones incluyeron cáncer de recto en 6 (3%) (2 en estadio I y 4 en estadio III); pólipos con displasia de alto grado en 4 (2%); carga progresiva de pólipos en 3 (1,5%), disfunción defecatoria en 2 (1%); y fuga anastomótica en 1 (0,5%). Entre 30 pacientes (18%) con ≥20 pólipos rectales en el momento de TAC/IRA, 8 pacientes (26%) se sometieron a proctectomía y 3 pacientes desarrollaron cáncer de recto (10%). Entre 134 pacientes (82%) con <20 pólipos, 8 pacientes (6%) se sometieron a proctectomía y 3 pacientes desarrollaron cáncer de recto (2%). El número de pólipos rectales en el momento de TAC/IRA se asoció con la probabilidad de proctectomía (OR 1,1, p <0,001), pero no con la incidencia de cáncer de recto (p = 0,3).LIMITACIÓN:Recopilación de datos retrospectivos.CONCLUSIÓN:Los pacientes con PAF seleccionados para TAC/IRA por el número de pólipos rectales tienen tasas bajas de proctectomía y cáncer de recto en comparación con los controles históricos. Con criterios de selección y vigilancia adecuados, TAC/IRA sigue siendo una opción de tratamiento importante y segura para los pacientes con PAF. (Pre-proofed version ).

Deoxyribonucleic acid methylation driven aberrations in pancreatic cancer-related pathways.

Pancreatic cancer (PanCa) presents a catastrophic disease with poor overall survival at advanced stages, with immediate requirement of new and effective treatment options. Besides genetic mutations, epigenetic dysregulation of signaling pathway-associated enriched genes are considered as novel therapeutic target. Mechanisms beneath the deoxyribonucleic acid methylation and its utility in developing of epi-drugs in PanCa are under trails. Combinations of epigenetic medicines with conventional cytotoxic treatments or targeted therapy are promising options to improving the dismal response and survival rate of PanCa patients. Recent studies have identified potentially valid pathways that support the prediction that future PanCa clinical trials will include vigorous testing of epigenomic therapies. Epigenetics thus promises to generate a significant amount of new knowledge of biological and medical importance. Our review could identify various components of epigenetic mechanisms known to be involved in the initiation and development of pancreatic ductal adenocarcinoma and related precancerous lesions, and novel pharmacological strategies that target these components could potentially lead to breakthroughs. We aim to highlight the possibilities that exist and the potential therapeutic interventions.

Higher Numbers of Examined Lymph Nodes Are Associated with Increased Survival in Resected, Treatment-Naïve, Node-Positive Esophageal, Gastric, Pancreatic, and Colon Cancers.

BACKGROUND OR PURPOSE: The role of extended lymphadenectomy as part of resection for lymph node (LN)-positive gastrointestinal (GI) malignancies remains controversial with no clear clinical guidance. The purpose of this retrospective study is to determine whether the number of LNs examined as part of GI malignancy resections affects overall survival (OS) among patients with node-positive esophageal, gastric, pancreatic, and colon cancers. METHODS: Participants with LN-positive GI cancers who were diagnosed between 2004 and 2015 and underwent oncologic resections were selected from National Cancer Database (NCDB). The primary predictor was the number of examined LNs categorized in tertiles. The effect on OS was measured by hazard ratio (HR) derived from multivariate Cox regression analyses. RESULTS: From 2004 to 2015, 1877, 10,086, 18,193, and 102,500 patients with LN-positive esophageal, gastric, pancreatic, and colon adenocarcinomas who did not receive neoadjuvant treatment and underwent oncologic tumor resection were registered in the NCDB. Using multivariate Cox proportional hazard modeling, greater LNs examined in surgically resected LN-positive GI cancers were found to be associated with increased OS for all histologies. This association was the strongest (as compared to the lowest tertile) for gastric cancer (middle tertile: HR = 0.91, 95% CI, 0.86-0.96, p = 0.001; highest tertile: HR = 0.73, 95% CI, 0.69-0.78, p < 0.001), followed by colon (highest tertile: HR = 0.86, 95% CI, 0.84-0.88, p < 0.001), esophageal (highest tertile: HR = 0.83, 95% CI, 0.72-0.95, p = 0.01), and pancreatic (highest tertile: HR = 0.93, 95% CI, 0.89-0.98, p = 0.002) cancers. DISCUSSION AND CONCLUSION: In patients with surgically resected node-positive GI malignancies who did not receive neoadjuvant systemic therapy, a higher number of examined LNs is associated with increased OS. This association is the strongest for gastric cancer, followed by colon, esophageal, and pancreatic cancers respectively.

Characteristics and outcomes of gallbladder cancer patients at the Tata Medical Center, Kolkata 2017-2019.

BACKGROUND: The north and north-eastern regions of India have among the highest incidence of gallbladder cancer (GBC) in the world. We report the clinicopathological charateristics and outcome of GBC patients in India. METHODS: Electronic medical records of patients diagnosed with GBC at Tata Medical Center, Kolkata between 2017 and 2019 were analyzed. RESULTS: There were 698 cases of confirmed GBC with a median age of 58 (IQR: 50-65) years and female:male ratio of 1.96. At presentation, 91% (496/544) had stage III/IV disease and 30% (189/640) had incidental GBC. The 2-year overall survival (OS) was 100% (95% CI: 100-100); 61% (95% CI: 45-83); 30% (95% CI: 21-43); and 9% (95% CI: 6-13) for stages I-IV, respectively (p = <0.0001).   For all patients, the 2-year OS in patients who had a radical cholecystectomy followed by adjuvant therapy (N = 36) was 50% (95% CI: 39-64), compared to 29% (95% CI: 22-38) for those who had a simple cholecystectomy and/or chemotherapy (N = 265) and 9% (95% CI: 6-14) in patients who were palliated (N = 107) (p = <0.0001). CONCLUSION: The combined surgical/chemotherapy approach for patients with stage II GBC showed the best outcomes. Early detection of GBC remains problematic with the majority of patients presenting with stage III-IV and who have a median survival of 9.1 months. Our data suggests that the tumor is chemoresponsive and multi-center collaborative clinical trials to identify alternative therapies are urgently required.

DNA methylome in pancreatic cancer identified novel promoter hyper-methylation in NPY and FAIM2 genes associated with poor prognosis in Indian patient cohort.

BACKGROUND: Pancreatic ductal adenocarcinoma (PDAC) is one of the leading cancers worldwide and has a poor survival, with a 5-year survival rate of only 8.5%. In this study we investigated altered DNA methylation associated with PDAC severity and prognosis. METHODS: Methylome data, generated using 450 K bead array, was compared between paired PDAC and normal samples in the TCGA cohort (n = 9) and our Indian cohort (n = 7). The total Indian Cohort (n = 75) was split into cohort 1 (n = 7), cohort 2 (n = 22), cohort 3 (n = 26) and cohort 4 (n = 20).Validation of differential methylation (6 selected CpG loci) and associated gene expression for differentially methylated genes (10 selected gDMs) were carried out in separate validation cohorts, using MSP, RT-PCR and IHC correlations between methylation and gene expression were observed in TCGA, GTEx cohorts and in validation cohorts. Kaplan-Meier survival analysis was done to study differential prognosis, during 2-5 years of follow-up. RESULTS: We identified 156 DMPs, mapped to 91 genes (gDMs), in PDAC; 68 (43.5%) DMPs were found to be differentially methylated both in TCGA cohort and our cohort, with significant concordance at hypo- and hyper-methylated loci. Enrichments of "regulation of ion transport", "Interferon alpha/beta signalling", "morphogenesis and development" and "transcriptional dysregulation" pathways were observed among 91 gDMs. Hyper-methylation of NPY and FAIM2 genes with down-regulated expression in PDAC, were significantly associated with poor prognosis in the Indian patient cohort. CONCLUSIONS: Ethnic variations among populations may determine the altered epigenetic landscape in the PDAC patients of the Indian cohort. Our study identified novel differentially methylated genes (mainly NPY and FAIM2) and also validated the previously identified differentially methylated CpG sites associated with PDAC cancer patient's survival. Comparative analysis of our data with TCGA and CPTAC cohorts showed that both NPY and FAIM2 hyper-methylation and down-regulations can be novel epigenetically regulated genes in the Indian patient population, statistically significantly associated with poor survival and advanced tumour stages.

Transverse oscillating bubble enhanced laser-driven betatron X-ray radiation generation.

Ultrafast high-brightness X-ray pulses have proven invaluable for a broad range of research. Such pulses are typically generated via synchrotron emission from relativistic electron bunches using large-scale facilities. Recently, significantly more compact X-ray sources based on laser-wakefield accelerated (LWFA) electron beams have been demonstrated. In particular, laser-driven sources, where the radiation is generated by transverse oscillations of electrons within the plasma accelerator structure (so-called betatron oscillations) can generate highly-brilliant ultrashort X-ray pulses using a comparably simple setup. Here, we experimentally demonstrate a method to markedly enhance the parameters of LWFA-driven betatron X-ray emission in a proof-of-principle experiment. We show a significant increase in the number of generated photons by specifically manipulating the amplitude of the betatron oscillations by using our novel Transverse Oscillating Bubble Enhanced Betatron Radiation scheme. We realize this through an orchestrated evolution of the temporal laser pulse shape and the accelerating plasma structure. This leads to controlled off-axis injection of electrons that perform large-amplitude collective transverse betatron oscillations, resulting in increased radiation emission. Our concept holds the promise for a method to optimize the X-ray parameters for specific applications, such as time-resolved investigations with spatial and temporal atomic resolution or advanced high-resolution imaging modalities, and the generation of X-ray beams with even higher peak and average brightness.

Establishment of Patient-Derived Succinate Dehydrogenase-Deficient Gastrointestinal Stromal Tumor Models for Predicting Therapeutic Response.

PURPOSE: Gastrointestinal stromal tumor (GIST) is the most common sarcoma of the gastrointestinal tract, with mutant succinate dehydrogenase (SDH) subunits (A-D) comprising less than 7.5% (i.e., 150-200/year) of new cases annually in the United States. Contrary to GISTs harboring KIT or PDGFRA mutations, SDH-mutant GISTs affect adolescents/young adults, often metastasize, and are frequently resistant to tyrosine kinase inhibitors (TKI). Lack of human models for any SDH-mutant tumors, including GIST, has limited molecular characterization and drug discovery. EXPERIMENTAL DESIGN: We describe methods for establishing novel patient-derived SDH-mutant (mSDH) GIST models and interrogated the efficacy of temozolomide on these tumor models in vitro and in clinical trials of patients with mSDH GIST. RESULTS: Molecular and metabolic characterization of our patient-derived mSDH GIST models revealed that these models recapitulate the transcriptional and metabolic hallmarks of parent tumors and SDH deficiency. We further demonstrate that temozolomide elicits DNA damage and apoptosis in our mSDH GIST models. Translating our in vitro discovery to the clinic, a cohort of patients with SDH-mutant GIST treated with temozolomide (n = 5) demonstrated a 40% objective response rate and 100% disease control rate, suggesting that temozolomide represents a promising therapy for this subset of GIST. CONCLUSIONS: We report the first methods to establish patient-derived mSDH tumor models, which can be readily employed for understanding patient-specific tumor biology and treatment strategies. We also demonstrate that temozolomide is effective in patients with mSDH GIST who are refractory to existing chemotherapeutic drugs (namely, TKIs) in clinic for GISTs, bringing a promising treatment option for these patients to clinic.See related commentary by Blakely et al., p. 3.

Can the CROSS protocol be safely implemented in real world scenario with broader eligibility criteria? Experience from a tertiary care centre in India.

BACKGROUND: The Chemoradiotherapy for Oesophageal Cancer Followed by Surgery Study (CROSS) trial established a new benchmark in the management of oesophageal cancer with neoadjuvant chemoradiation followed by surgery with a marked benefit for squamous cell carcinomas (SCCs). We evaluate if the CROSS protocol can be safely implemented with a broader eligibility criteria in a real-world setting. METHODS: A retrospective analysis of 80 patients of SCC oesophagus was performed, who were treated with neoadjuvant chemoradiation with radiation therapy (RT) to 41.4 Gy/23 Fr/4.5 weeks and weekly paclitaxel and carboplatin, followed by surgery at our institute between 2012 and 2019. Eligibility for the use of this regimen was expanded beyond the limits of size and stage allowed in the CROSS trial. RESULTS: The median age of this cohort was 57 years (range: 39-78 years). Most of the patients (77/80; 96.3%) had T3 disease and 25% patients (20/80) had N2/N3 disease. Thirty-three patients (41.3%) had the disease beyond CROSS eligibility criteria. All patients completed planned course of RT and five cycles of weekly chemotherapy were received by 61 patients (76.2%). Overall pathological complete response (pCR) could be achieved in 33 patients (41.3%). Among 33 CROSS ineligible patients, 14 (42.4%) had pCR. Acute grade 3 dysphagia and grade ≥ 3 neutropenia were seen in seven cases (8.3%) and nine cases (10.7%), respectively. At a median follow-up of 16 months, 1-year and 2-year overall survival (OS) were 84.4% (95% confidence interval (CI): 73.5%-91.1%) and 76.3% (95% CI: 63.2%-85.2%), respectively, for the entire cohort. For CROSS ineligible patients, 1-year and 2-year OS were 82% (95% CI: 61.8%-92.2%) and 72.7% (95% CI: 50.4%-86.2%), respectively. On univariate analysis, patients who had pathologically N0 disease had significantly better 2-year OS (85.7% versus 48.4%; p = 0.03) as compared to pathologically N+ patients. On univariate and multivariate analysis, there was no significant difference in OS and progression free survival between CROSS eligible and CROSS ineligible patients. CONCLUSION: CROSS protocol can be safely implemented for carefully selected patients of SCC oesophagus outside clinical trial settings with expanded eligibility criteria.

KITlow Cells Mediate Imatinib Resistance in Gastrointestinal Stromal Tumor.

Gastrointestinal stromal tumor (GIST) is commonly driven by oncogenic KIT mutations that are effectively targeted by imatinib (IM), a tyrosine kinase inhibitor (TKI). However, IM does not cure GIST, and adjuvant therapy only delays recurrence in high-risk tumors. We hypothesized that GIST contains cells with primary IM resistance that may represent a reservoir for disease persistence. Here, we report a subpopulation of CD34+KITlow human GIST cells that have intrinsic IM resistance. These cells possess cancer stem cell-like expression profiles and behavior, including self-renewal and differentiation into CD34+KIThigh progeny that are sensitive to IM treatment. We also found that TKI treatment of GIST cell lines led to induction of stem cell-associated transcription factors (OCT4 and NANOG) and concomitant enrichment of the CD34+KITlow cell population. Using a data-driven approach, we constructed a transcriptomic-oncogenic map (Onco-GPS) based on the gene expression of 134 GIST samples to define pathway activation during GIST tumorigenesis. Tumors with low KIT expression had overexpression of cancer stem cell gene signatures consistent with our in vitro findings. Additionally, these tumors had activation of the Gas6/AXL pathway and NF-κB signaling gene signatures. We evaluated these targets in vitro and found that primary IM-resistant GIST cells were effectively targeted with either single-agent bemcentinib (AXL inhibitor) or bardoxolone (NF-κB inhibitor), as well as with either agent in combination with IM. Collectively, these findings suggest that CD34+KITlow cells represent a distinct, but targetable, subpopulation in human GIST that may represent a novel mechanism of primary TKI resistance, as well as a target for overcoming disease persistence following TKI therapy.

Location of Gastrointestinal Stromal Tumor (GIST) in the Stomach Predicts Tumor Mutation Profile and Drug Sensitivity.

PURPOSE: Gastrointestinal stromal tumors (GIST) commonly arise in different regions of the stomach and are driven by various mutations (most often in KIT, PDGFRA, and SDHx). We hypothesized that the anatomic location of gastric GIST is associated with unique genomic profiles and distinct driver mutations. EXPERIMENTAL DESIGN: We compared KIT versus non-KIT status with tumor location within the National Cancer Database (NCDB) for 2,418 patients with primary gastric GIST. Additionally, we compiled an international cohort (TransAtlantic GIST Collaborative, TAGC) of 236 patients and reviewed sequencing results, cross-sectional imaging, and operative reports. Subgroup analyses were performed for tumors located proximally versus distally. Risk factors for KIT versus non-KIT tumors were identified using multivariate regression analysis. A random forest machine learning model was then developed to determine feature importance. RESULTS: Within the NCDB cohort, non-KIT mutants dominated distal tumor locations (P < 0.03). Proximal GIST were almost exclusively KIT mutant (96%) in the TAGC cohort, whereas 100% of PDGFRA and SDH-mutant GIST occurred in the distal stomach. On multivariate regression analysis, tumor location was associated with KIT versus non-KIT mutations. Using random forest machine learning analysis, stomach location was the most important feature for predicting mutation status. CONCLUSIONS: We provide the first evidence that the mutational landscape of gastric GIST is related to tumor location. Proximal gastric GIST are overwhelmingly KIT mutant, irrespective of morphology or age, whereas distal tumors display non-KIT genomic diversity. Anatomic location of gastric GIST may therefore provide immediate guidance for clinical treatment decisions and selective confirmatory genomic testing when resources are limited.

TGF-ß1-mediated transition of resident fibroblasts to cancer-associated fibroblasts promotes cancer metastasis in gastrointestinal stromal tumor.

Cancer-associated fibroblasts (CAFs) are the most abundant cells in the tumor microenvironment. Crosstalk between tumor cells and CAFs contributes to tumor survival in most epithelial cancers. Recently, utilizing gastrointestinal stromal tumor (GIST) as a model for sarcomas, we identified paracrine networks by which CAFs promote tumor progression and metastasis. However, the mechanisms by which CAFs arise in sarcomas remain unclear. Here, RNA sequencing analysis revealed that transforming growth factor-ß1 (TGF-ß1) is highly expressed in both tumor cells and CAFs. To determine the functional role of TGF-ß1, we treated normal gastric fibroblasts (GFs) with recombinant TGF-ß1, which caused the GFs to adopt a more stellate morphology, as well as increased the mRNA expression of CAF-mediated genes (CCL2, RAB3B, and TNC) and genes encoding fibroblast growth factors (FGFs). Moreover, while either GIST or CAF conditioned media enhanced the transition from GFs to CAFs, a TGF-ß1-blocking antibody attenuated this effect. Transwell migration assays revealed that the TGF-ß1-mediated transition from GFs to CAFs enhanced tumor cell migration. This migratory effect was abrogated by an anti-TGF-ß1 antibody, suggesting that TGF-ß1 secreted from GIST cells or CAFs is associated with GIST migration via GF-to-CAF transition. In addition, the murine spleen-to-liver metastasis model showed that GF pre-treated with TGF-ß1 promoted GIST metastasis. Collectively, these findings reveal unappreciated crosstalk among tumor cells, CAFs, and normal resident fibroblasts in the stroma of sarcomas, which enhances a GF-to-CAF transition associated with tumor migration and metastasis.

Cancer-associated fibroblast secretion of PDGFC promotes gastrointestinal stromal tumor growth and metastasis.

Targeted therapies for gastrointestinal stromal tumor (GIST) are modestly effective, but GIST cannot be cured with single agent tyrosine kinase inhibitors. In this study, we sought to identify new therapeutic targets in GIST by investigating the tumor microenvironment. Here, we identified a paracrine signaling network by which cancer-associated fibroblasts (CAFs) drive GIST growth and metastasis. Specifically, CAFs isolated from human tumors were found to produce high levels of platelet-derived growth factor C (PDGFC), which activated PDGFC-PDGFRA signal transduction in GIST cells that regulated the expression of SLUG, an epithelial-mesenchymal transition (EMT) transcription factor and downstream target of PDGFRA signaling. Together, this paracrine induce signal transduction cascade promoted tumor growth and metastasis in vivo. Moreover, in metastatic GIST patients, SLUG expression positively correlated with tumor size and mitotic index. Given that CAF paracrine signaling modulated GIST biology, we directly targeted CAFs with a dual PI3K/mTOR inhibitor, which synergized with imatinib to increase tumor cell killing and in vivo disease response. Taken together, we identified a previously unappreciated cellular target for GIST therapy in order to improve disease control and cure rates.

Commission on Cancer Facility Type is Associated with Overall Survival in Patients with Gastric Adenocarcinoma in the United States.

BACKGROUND: In the United States, "high-volume" centers for gastric cancer treat significantly fewer cases per year compared with centers in Asia. Factors associated with oncologic outcomes, aside from volume, are poorly understood. METHODS: Patients with gastric adenocarcinoma between 2004 and 2015 were analyzed in the NCDB cohort. Commission on Cancer facility types were classified as either Academic/Research Programs (ARP) or Non-Academic Programs (NAP). Factors associated with treatment at facility type were assessed by logistic regression. Overall survival was compared between facility types by Cox proportional hazard models. RESULTS: Thirty-nine percent of patients were treated at ARPs. In multivariable analysis, patients treated at ARPs were younger, healthier (Charlson-Deyo score), and had lower AJCC stage. Treatment at an ARP was associated with superior median OS compared with treatment at a NAP (17.3 months vs. 11.1 months, respectively, P < 0.001,) and in each stage of disease. Treatment of stages II and III patients at ARPs increased over time. Among patients with stages II and III disease, adherence to therapy guidelines was higher and postoperative mortality was lower at ARPs. CONCLUSION: Although patients at ARPs tend to have favorable characteristics, superior overall survival may also be due to better adherence to therapy guidelines and capacity to rescue after surgical complications.

Cost-effectiveness Analysis of Genetic Testing and Tailored First-Line Therapy for Patients With Metastatic Gastrointestinal Stromal Tumors.

Importance: Gastrointestinal stromal tumor (GIST) is frequently driven by oncogenic KIT variations. Imatinib targeting of KIT marked a new era in GIST treatment and ushered in precision oncological treatment for all solid malignant neoplasms. However, studies on the molecular biological traits of GIST have found that tumors respond differentially to imatinib dosage based on the KIT exon with variation. Despite this knowledge, few patients undergo genetic testing at diagnosis, and empirical imatinib therapy remains routine. Barriers to genetic profiling include concerns about the cost and utility of testing. Objective: To determine whether targeted gene testing (TGT) is a cost-effective diagnostic for patients with metastatic GIST from the US payer perspective. Design, Setting, and Participants: This economic evaluation developed a Markov model to compare the cost-effectiveness of TGT and tailored first-line therapy compared with empirical imatinib therapy among patients with a new diagnosis of metastatic GIST. The main health outcome, quality-adjusted life years (QALYs), and costs were obtained from the literature, and transitional probabilities were modeled from disease progression and survival estimates from randomized clinical trials of patients with metastatic GIST. Data analyses were conducted October 2019 to January 2020. Exposure: TGT and tailored first-line therapy. Main Outcomes and Measures: The primary outcome was QALYs and cost. Cost-effectiveness was defined using an incremental cost-effectiveness ratio, with an incremental cost-effectiveness ratio less than $100 000/QALY considered cost-effective. One-way and probabilistic sensitivity analyses were conducted to assess model stability. Results: Therapy directed by TGT was associated with an increase of 0.10 QALYs at a cost of $9513 compared with the empirical imatinib approach, leading to an incremental cost-effectiveness ratio of $92 100. These findings were sensitive to the costs of TGT, drugs, and health utility model inputs. Therapy directed by TGT remained cost-effective for genetic testing costs up to $3730. Probabilistic sensitivity analysis found that TGT-directed therapy was considered cost-effective 70% of the time. Conclusions and Relevance: These findings suggest that using genetic testing to match treatment of KIT variations to imatinib dosing is a cost-effective approach compared with empirical imatinib.