Antineoplastic platinum agents are used in first-line treatment of ovarian cancer, but treatment failure frequently results from platinum drug resistance. Emerging observations suggest a role of reactive oxygen species (ROS) in the resistance of cancer drugs including platinum drugs. However, the molecular link between ROS and cellular survival pathway is poorly understood. Using quantitative high-throughput combinational screen (qHTCS) and genomic sequencing, we show that in platinum-resistant ovarian cancer elevated ROS levels sustain high level of IL-11 by stimulating FRA1-mediated IL-11 expression and increased IL-11 causes resistance to platinum drugs by constitutively activating JAK2-STAT5 via an autocrine mechanism. Inhibition of JAK2 by LY2784544 or IL-11 by anti-IL-11 antibody overcomes the platinum resistance in vitro or in vivo. Significantly, clinic studies also confirm the activated IL-11-JAK2 pathway in platinum-resistant ovarian cancer patients, which highly correlates with poor prognosis. These findings not only identify a novel ROS-IL-11-JAK2-mediated platinum resistance mechanism but also provide a new strategy for using LY2784544- or IL-11-mediated immunotherapy to treat platinum-resistant ovarian cancer.

Calretinin is an intracellular calcium-binding EF-hand protein of the calmodulin superfamily. It plays a role in diverse cellular functions, including message targeting and intracellular calcium signaling. It is expressed in the mesothelium, mast cells, some neural cells, and fat cells, among others. Because of its relative specificity for mesothelial neoplasms, calretinin is widely used as one of the primary immunohistochemical markers for malignant mesothelioma and in differentiating it from adenocarcinoma. On the basis of our sporadic observation on calretinin immunoreactivity in desmoid fibromatosis, we systematically evaluated calretinin, keratin cocktail (AE1/AE3), and WT1 immunoreactivity in 268 fibroblastic/myofibroblastic neoplasms. Calretinin was observed in 75% (44/58) of desmoid fibromatosis, 50% (21/42) of proliferative fasciitis, 23% (8/35) of nodular fasciitis, 33% (13/40) of benign fibrous histiocytoma, 35% (22/62) of malignant fibrous histiocytoma, and 13% (4/31) of solitary fibrous tumors but not in normal connective tissue fibroblasts at various sites. Keratin AE1/AE3 immunoreactivity was also commonly (6/13) present in the large ganglion-like cells of proliferative fasciitis and sometimes in nodular fasciitis (3/35), solitary fibrous tumor (3/27), and malignant fibrous histiocytoma (9/62). Nuclear immunoreactivity for WT1 or keratin 5 positivity was not detected in myofibroblastic tumors. On the basis of these observations, it can be concluded that calretinin and focal keratin immunoreactivity is fairly common in benign and malignant fibroblastic and myofibroblastic lesions. Calretinin-positive and keratin-positive spindle cells in desmoid and nodular fasciitis or calretinin-positive ganglion-like cells in proliferative fasciitis should not be confused with elements of epithelioid or sarcomatoid mesothelioma. These diagnostic pitfalls can be avoided with careful observation of morphology, quantitative differences in keratin expression, and use of additional immunohistochemical markers such keratin 5 and WT1 to verify true epithelial and mesothelial differentiation typical of mesothelioma.

Background Patients with von Hippel-Lindau disease (VHL) commonly develop pancreatic cysts and neuroendocrine tumors (PNETs). Solid microcystic serous adenoma (SMSA), a rare tumor described in VHL patients, can be mistaken for PNET on imaging. Methods Clinical, pathologic and radiologic data were reviewed on VHL patients who underwent surgery for a pre-operative diagnosis of PNET since 1994 at one institution. Blinded to the pathological diagnoses, radiologists reassessed available imaging. Results For 55 patients, 79 pancreatectomies were performed for presumed PNETs. Ten (18.2%) patients underwent 12 (15.2%) resections for tumors diagnosed as SMSA on final pathology. The average size of a SMSA leading to surgery was 3.6 ±0.4 cm. Four out of 11 SMSAs were still mistaken for PNETs when imaging was reassessed. Mean FDG-PET SUV was higher for 17 PNETs (12.1 ±1.2) compared to 6 SMSAs (4.2 ±0.5; p=0.002). The mean doubling time of SMSAs and PNETs was similar. Seven (15.2%) patients with pathologically-proven PNETs had malignant disease. Conclusions SMSAs can mimic PNETs on non-functional imaging; FDG-PET may help differentiate them. A high index of suspicion is needed to minimize operations performed for SMSA and to counsel VHL patients of their risks of undergoing surgery for a lesion with no known malignant potential.

Von Hippel-Lindau (VHL) syndrome is an inherited cancer syndrome in which 8-17% of germline mutation carriers develop pancreatic neuroendocrine tumors (PNETs). There is limited data on prognostic markers for PNETs other than Ki-67, which is included in the World Health Organization classification system. Recently, specific genes and pathways have been identified by whole exome sequencing which may be involved in the tumorigenesis of PNETs and may be markers of disease aggressiveness. The objective of this study was to identify molecular markers of aggressive disease in VHL-associated PNETs. The protein expression of 8 genes (PTEN, CHGA, CHGB, ATRX, DAXX, CC-3, VEGF, TP53) was analyzed in PNETs by immunohistochemistry and compared to clinical data, VHL genotype, functional imaging results, and pathologic findings. Subcellular distribution of PTEN, CHGA and ATRX were significantly different by WHO classifications (p<0.05). There was decreased PTEN nuclear to cytoplasmic ratio (p<0.01) and decreased CHGA nuclear expression (p=0.03) in malignant samples as compared to benign. Lower cytoplasmic CHGB expression (p=0.03) was associated with malignant tumors and metastasis. Higher nuclear expression of PTEN was associated with VHL mutations in exon 3 (p=0.04). Higher PTEN and CHGB expression was associated with higher FDG-PET avidity (p<0.05). Cytoplasmic expression of CC-3 was associated with higher serum Chromogranin A levels (σ=0.72, p= 0.02). Lastly, greater cytoplasmic expression of p53 was associated with metastasis. Our findings suggest that altered PTEN, ATRX, CHGA and CHGB expression are associated with aggressive PNET phenotype in VHL and may serve as useful adjunct prognostic markers to Ki-67 in PNETs.