PDGFRß Signaling Cooperates with ß-Catenin to Modulate c-Abl and Biologic Behavior of Desmoid-Type Fibromatosis.

PURPOSE: This study sought to identify ß-catenin targets that regulate desmoid oncogenesis and determine whether external signaling pathways, particularly those inhibited by sorafenib (e.g., PDGFRß), affect these targets to alter natural history or treatment response in patients. EXPERIMENTAL DESIGN: In vitro experiments utilized primary desmoid cell lines to examine regulation of ß-catenin targets. Relevance of results was assessed in vivo using Alliance trial A091105 correlative biopsies. RESULTS: CTNNB1 knockdown inhibited hypoxia-regulated gene expression in vitro and reduced levels of HIF1α protein. ChIP-seq identified ABL1 as a ß-catenin transcriptional target that modulated HIF1α and desmoid cell proliferation. Abrogation of either CTNNB1 or HIF1A inhibited desmoid cell-induced VEGFR2 phosphorylation and tube formation in endothelial cell co-cultures. Sorafenib inhibited this activity directly but also reduced HIF1α protein expression and c-Abl activity while inhibiting PDGFRß signaling in desmoid cells. Conversely, c-Abl activity and desmoid cell proliferation were positively regulated by PDGF-BB. Reduction in PDGFRß and c-Abl phosphorylation was commonly observed in biopsy samples from patients after treatment with sorafenib; markers of PDGFRß/c-Abl pathway activation in baseline samples were associated with tumor progression in patients on the placebo arm and response to sorafenib in patients receiving treatment. CONCLUSIONS: The ß-catenin transcriptional target ABL1 is necessary for proliferation and maintenance of HIF1α in desmoid cells. Regulation of c-Abl activity by PDGF signaling and targeted therapies modulates desmoid cell proliferation, thereby suggesting a reason for variable biologic behavior between tumors, a mechanism for sorafenib activity in desmoids, and markers predictive of outcome in patients.

The Evolving Management of Desmoid Fibromatosis.

Desmoid fibromatosis is a rare disease caused by genetic alterations that activate ß-catenin. The tumors were previously treated with aggressive surgeries but do not metastasize and may regress spontaneously. For these reasons, in the absence of symptoms and when growth would not induce significant complications, active observation is considered first-line therapy. When intervention is required, surgery can be considered based on anatomy and risk of postoperative recurrence, but increasingly nonoperative therapies such as liposomal doxorubicin or sorafenib are prescribed. Cryoablation, chemoembolization, and high-intensity focused ultrasound can also be used to obtain local control in selected patients.

Case report of intestinal non-rotation, heterotaxy, and polysplenia in a patient with pancreatic cancer.

RATIONALE: Heterotaxy with polysplenia is an extremely rare congenital condition resulting from abnormal arrangement of organs in the abdominal and thoracic cavities during embryologic development. When a malignancy such as pancreatic cancer develops under these conditions, surgical resection becomes particularly complex. This case report demonstrates successful pancreatic cancer resection despite the patient's complicated anatomy. PATIENT CONCERNS: An 82-year-old female presented to our institution with complaints of mild right upper quadrant pain radiating to the mid-epigastric region. DIAGNOSES: Physical examination revealed jaundice with scleral icterus consistent with obstructive jaundice. Radiographic imaging revealed hepatic duct dilation with several anatomic anomalies including small bowel location in the right upper abdomen, cecum, and appendix in the left lower quadrant, reversed superior mesenteric artery and superior mesenteric vein positions, and right-sided duodenal-jejunal flexture as well as an entirely right-sided pancreas, and left lower pelvis with ≥6 separate splenules. These findings resulted in a diagnosis of heterotaxy syndrome with polysplenia. INTERVENTIONS: Careful preoperative planning and total pancreatectomy was performed without complication. OUTCOMES: The patient recovered well. Pathologic examination of the pancreatic mass revealed moderately/poorly differentiated invasive pancreatic duct adenocarcinoma. The patient remains alive and well without signs of recurrent disease at the 2-year follow-up. LESSONS: Given the wide range of anatomical variants observed in patients with heterotaxy syndrome, a thorough radiologic assessment is necessary before engaging in any surgical procedure. In our case, preoperative identification of the various anatomic anomalies, such as the short and vertically oriented pancreas, the porta hepatis position anterior to the duodenum, the nonrotation of the intestines and the anomalous origin of the right hepatic artery allowed us to perform a safe and uncomplicated total pancreatectomy.