Clinicopathologic Analysis and Molecular Profiling of Ovarian Steroid Cell Tumors.

Ovarian steroid and Leydig cell tumors (SCT and LCT, respectively) are rare stromal tumors, with aggressive behavior described in approximately one third of SCTs. Previously reported features potentially predictive of malignancy include size ≥7 cm, gross hemorrhage, necrosis, grade 2 or 3 nuclear atypia, and mitoses ≥2/10 HPFs; however, no subsequent studies have corroborated these findings. Herein, we evaluated a series of 25 tumors (21 SCT, 4 LCT) to explore their clinicopathologic and molecular features. Patients ranged from 16 to 79 years (median: 53 y) and all tumors were FIGO stage I. Recurrences occurred in 3 patients, all of whom died from disease. At least 1 atypical feature was identified in 63% of SCT/LCT and included hemorrhage (n=9), grade 2 or 3 atypia (n=7), mitoses≥2/10 HPFs (n=7), size≥7.0 cm (n=6), and necrosis (n=2); only malignant SCTs demonstrated 4 or 5 atypical features. Next-generation sequencing revealed malignant SCTs were genomically unstable, with uncommon and nonrecurring gene-level alterations ( MDM2/CDK4 coamplification, ATRX rearrangement, BAP1 mutation). One SCT with limited follow-up harbored FH and TP53 mutations and occasional arm-level copy number alterations, while all other sequenced tumors (n=7) were genomically stable; 1 had a CTNNB1 mutation and another a CASP10 mutation. In summary, the presence of at least 1 atypical feature is common in SCT/LCT, but most patients demonstrate a benign clinical course. Genomic alterations are infrequent but occur in malignant SCTs as well as a subset of benign SCTs. Molecular analysis of additional malignant SCTs is necessary to identify recurring and/or potentially actionable targets.

BCL3 expression promotes resistance to alkylating chemotherapy in gliomas.

The response of patients with gliomas to alkylating chemotherapy is heterogeneous. However, there are currently no universally accepted predictors of patient response to these agents. We identify the nuclear factor κB (NF-κB) co-regulator B cell CLL/lymphoma 3 (BCL-3) as an independent predictor of response to temozolomide (TMZ) treatment. In glioma patients with tumors that have a methylated O6-methylguanine DNA methyltransferase (MGMT) promoter, high BCL-3 expression was associated with a poor response to TMZ. Mechanistically, BCL-3 promoted a more malignant phenotype by inducing an epithelial-to-mesenchymal transition in glioblastomas through promoter-specific NF-κB dimer exchange. Carbonic anhydrase II (CAII) was identified as a downstream factor promoting BCL-3-mediated resistance to chemotherapy. Experiments in glioma xenograft mouse models demonstrated that the CAII inhibitor acetazolamide enhanced survival of TMZ-treated animals. Our data suggest that BCL-3 might be a useful indicator of glioma response to alkylating chemotherapy and that acetazolamide might be repurposed as a chemosensitizer for treating TMZ-resistant gliomas.

Afatinib Activity in Platinum-Refractory Metastatic Urothelial Carcinoma in Patients With ERBB Alterations.

PURPOSE: Somatic mutations and copy number variation in the ERBB family are frequent in urothelial carcinoma (UC) and may represent viable therapeutic targets. We studied whether afatinib (an oral, irreversible inhibitor of the ErbB family) has activity in UC and if specific ERBB molecular alterations are associated with clinical response. PATIENTS AND METHODS: In this phase II trial, patients with metastatic platinum-refractory UC received afatinib 40 mg/day continuously until progression or intolerance. The primary end point was 3-month progression-free survival (PFS3). Prespecified tumor analysis for alterations in EGFR, HER2, ERBB3, and ERBB4 was conducted. RESULTS: The first-stage enrollment goal of 23 patients was met. Patient demographic data included: 78% male, median age 67 years (range, 36 to 82 years), hemoglobin < 10 g/dL in 17%, liver metastases in 30%, median time from prior chemotherapy of 3.6 months, and Eastern Cooperative Oncology Group performance status ≤ 1 in 100%. No unexpected toxicities were observed; two patients required dose reduction for grade 3 fatigue and rash. Overall, five of 23 patients (21.7%) met PFS3 (two partial response, three stable disease). Notably, among the 21 tumors analyzed, five of six patients (83.3%) with HER2 and/or ERBB3 alterations achieved PFS3 (PFS = 10.3, 7.0, 6.9, 6.3, and 5.0 months, respectively) versus none of 15 patients without alterations (P < .001). Three of four patients with HER2 amplification and three of three patients with ERBB3 somatic mutations (G284R, V104M, and R103G) met PFS3. One patient with both HER2 amplification and ERBB3 mutation never progressed on therapy, but treatment was discontinued after 10.3 months as a result of depressed ejection fraction. The median time to progression/discontinuation was 6.6 months in patients with HER2/ERBB3 alterations versus 1.4 months in patients without alterations (P < .001). CONCLUSION: Afatinib demonstrated significant activity in patients with platinum-refractory UC with HER2 or ERBB3 alterations. The potential contribution of ERBB3 to afatinib sensitivity is novel. Afatinib deserves further investigation in molecularly selected UC.

Discovery of previously unidentified genomic disorders from the duplication architecture of the human genome.

Genomic disorders are characterized by the presence of flanking segmental duplications that predispose these regions to recurrent rearrangement. Based on the duplication architecture of the genome, we investigated 130 regions that we hypothesized as candidates for previously undescribed genomic disorders. We tested 290 individuals with mental retardation by BAC array comparative genomic hybridization and identified 16 pathogenic rearrangements, including de novo microdeletions of 17q21.31 found in four individuals. Using oligonucleotide arrays, we refined the breakpoints of this microdeletion, defining a 478-kb critical region containing six genes that were deleted in all four individuals. We mapped the breakpoints of this deletion and of four other pathogenic rearrangements in 1q21.1, 15q13, 15q24 and 17q12 to flanking segmental duplications, suggesting that these are also sites of recurrent rearrangement. In common with the 17q21.31 deletion, these breakpoint regions are sites of copy number polymorphism in controls, indicating that these may be inherently unstable genomic regions.

Drosophila myb exerts opposing effects on S phase, promoting proliferation and suppressing endoreduplication.

Drosophila melanogaster possesses a single gene, Dm myb, that is closely related to the vertebrate family of Myb genes, which encode transcription factors that are involved in regulatory decisions affecting cell proliferation, differentiation and apoptosis. The vertebrate Myb genes have been specifically implicated in regulating the G(1)/S transition of the cell cycle. Dm myb is expressed in all proliferating tissues, but not at detectable levels in endoreduplicating cells. Analysis of loss-of-function mutations in Dm myb revealed a block at the G(2)/M transition and mitotic defects, but did not directly implicate Dm myb function in the G(1/)S transition. We have used the Gal4-UAS binary system of ectopic expression to further investigate the function of Dm myb. Our results demonstrate that depending upon the type of cell cycle, ectopic Dm myb activity can exert opposing effects on S phase: driving DNA replication and promoting proliferation in diploid cells, even when developmental signals normally dictate cell cycle arrest; but suppressing endoreduplication in endocycling cells, an effect that can be overcome by induction of E2F. We also show that a C-terminally truncated DMyb protein, which is similar to an oncogenic form of vertebrate Myb, has more potent effects than the full-length protein, especially in endoreduplicating tissues. This finding indicates that the C terminus acts as a negative regulatory domain, which can be differentially regulated in a tissue-specific manner. Our studies help to resolve previous discrepancies regarding myb gene function in Drosophila and vertebrates. We conclude that in proliferating cells, Dm myb has the dual function of promoting S phase and M phase, while preserving diploidy by suppressing endoreduplication.