Uterine serous cancer (USC) is aggressive, and the majority of recurrent cases are chemoresistant. Because the receptor tyrosine kinase AXL promotes invasion and metastasis of USC and is implicated in chemoresistance in other cancers, we assessed the role of AXL in paclitaxel resistance in USC, determined the mechanism of action, and sought to restore chemosensitivity by inhibiting AXL in vitro and in vivo. We used small hairpin RNAs and BGB324 to knock down and inhibit AXL. We assessed sensitivity of USC cell lines to paclitaxel and measured paclitaxel intracellular accumulation in vitro in the presence or absence of AXL. We also examined the role of the epithelial-mesenchymal transition in AXL-mediated paclitaxel resistance. Finally, we treated USC xenografts with paclitaxel, BGB324, or paclitaxel plus BGB324 and monitored tumor burden. AXL expression was higher in chemoresistant USC patient tumors and cell lines than in chemosensitive tumors and cell lines. Knockdown or inhibition of AXL increased sensitivity of USC cell lines to paclitaxel in vitro and increased cellular accumulation of paclitaxel. AXL promoted chemoresistance even in cells that underwent the epithelial-mesenchymal transition in vitro. Finally, in vivo studies of combination treatment with BGB324 and paclitaxel showed a greater than 51% decrease in tumor volume after 2 weeks of treatment when compared to no treatment or single agent treatments (P<0.001). Our results show that AXL expression mediates chemoresistance independent of EMT and prevents accumulation of paclitaxel. This study supports the continued investigation of AXL as a clinical target, particularly in chemoresistant USC.

Ovarian cancer, one of the deadliest malignancies in female cancer patients, is characterized by recurrence and poor response to cytotoxic chemotherapies. Fewer than 30% of patients with resistant disease will respond to additional chemotherapy treatments. This study aims to determine whether and how inhibition of the receptor tyrosine kinase AXL can restore sensitivity to first-line platinum and taxane therapy in ovarian cancer. AXL staining was quantified in a patient tissue microarray and correlated with chemoresponse of patients. We used small hairpin RNAs to knock down AXL expression and the small-molecule inhibitor BGB324 to inhibit AXL and assessed sensitivity of cell lines and primary patientderived cells to chemotherapy. We quantified platinum accumulation by inductivity-coupled plasma phase mass spectrometry. Finally, we treated chemoresistant patient-derived xenografts with chemotherapy, BGB324, or chemotherapy plus BGB324 and monitored tumor burden. AXL expression was higher in chemoresistant patient tumors and cell lines than in chemosensitive tumors and cell lines. AXL staining significantly predicted chemoresponse. Knockdown and inhibition of AXL dose-dependently improved response to paclitaxel and carboplatin in both cell lines and primary cells. AXL inhibition increased platinum accumulation by 2-fold (*, P < 0.05). In vivo studies indicated that AXL inhibition enhanced the ability of chemotherapy to prevent tumor growth (****, P < 0.0001). AXL contributes to platinum and taxane resistance in ovarian cancer, and inhibition of AXL improves chemoresponse and accumulation of chemotherapy drugs. This study supports continued investigation into AXL as a clinical target.

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Objective To evaluate the use of as an aid in the identification of women who can safely undergo conservative, non-surgical management. Methods All patients referred to the Program in Women’s Oncology for surgery with a pelvic mass are evaluated at a prospective multidisciplinary tumor board (TB) where ROMA and imaging are used for management recommendations. This study evaluated women presented to TB with a pelvic mass between 2009 and 2013 who had either surgical or conservative management. Results Of the 498 patients assessed, 392 (79%) had benign disease, 22 (4%) had LMP tumors, 28 (6%) had stage I-II epithelial ovarian cancer (EOC), 36 (7%) had stage III-IV EOC and 20 (4%) had non-EOC. Using clinical assessment in conjunction with ROMA, the TB recommended observation in 188 (37.8%) women. All patients diagnosed with an invasive malignancy were recommended for surgery by the TB. In the 315 patients managed surgically, 212 were found to have benign disease and 84 women were diagnosed with an invasive malignancy. The sensitivity for the initial TB recommendations using ROMA in conjunction with clinical judgment for detecting malignancy was 100% with a specificity of 47.7% and a NPV of 100%. When including low malignant potential tumors the sensitivity was 99.1%. For stage I-IV EOC ROMA alone had a sensitivity of 95.3%. Conclusions ROMA in conjunction with clinical assessment can safely identify women for conservative management.