Citations

SummaryLong‐term outcomes and updated clinical efficacy and safety data were evaluated for newly‐diagnosed multiple myeloma patients treated on a phase II study of bortezomib and pegylated liposomal doxorubicin (PegLD). Out of 61 patients, the overall response rate was 57% and the near‐complete/complete response rate was 7%. Patients aged ≥65 years old had a higher incidence of treatment‐related ≥Grade 3 non‐haematological toxicity (80% vs. 51%, P = 0·020). Median overall survival was 5·6 years and negatively impacted by the presence of International Staging System stage III disease, underscoring the need for novel treatment strategies for this group of patients.

Vasculogenesis and angiogenesis are controlled by vascular permeability factor/vascular endothelial growth factor A (VEGF). Dysregulation of these physiological processes contributes to the pathologies of heart disease, cancer and stroke. Rho GTPase proteins play an integral role in VEGF-mediated formation and maintenance of blood vessels. The regulatory functions of RhoA and RhoB in vasculogenesis and angiogenesis are well defined, whereas the purpose of RhoC remains poorly understood. Here, we describe how RhoC promotes vascular homeostasis by modulating endothelial cell migration, proliferation, and permeability. RhoC stimulates proliferation of human umbilical vein endothelial cells (HUVEC) by stabilizing nuclear β-catenin, which promotes transcription of cyclin D1 and subsequently drives cell cycle progression. RhoC negatively regulates endothelial cell migration through MAPK and downstream MLC-2 signaling and decreases vascular permeability through downregulation of the phospholipase Cγ (PLCγ)/Ca2+/eNOS cascade in HUVEC. Using a VEGF-inducible zebrafish (Danio rerio) model, we observed significantly less vascular permeability in RhoC morpholino (MO)-injected zebrafish than control MO-injected zebrafish. Taken together, our findings suggest RhoC is a key regulator of vascular homeostasis in endothelial cells.

Circulating tumor cells (CTCs) in blood are associated with poor survival of patients with breast, prostate, or colon cancer. We hypothesized that CTCs are associated with poor survival of patients with cholangiocarcinoma (CCA). Eighty‐eight patients with CCA were prospectively enrolled at Mayo Clinic Rochester between June 2010 and September 2014. The CellSearch system by Veridex was used for detection of CTCs in peripheral blood. Associations between CTC, patient and tumor characteristics, and survival were examined using the Cox's proportional hazards model. Fifteen patients (17%) were positive for CTC ≥2 and 8 patients (9%) for CTC ≥5. CTCs were associated with tumor extent. CTC ≥2 (hazard ratio [HR]: 2.5; 95% confidence interval [CI]: 1.1‐5.4; P = 0.02) and CTC ≥5 (HR, 4.1; 95% CI: 1.4‐10.8; P = 0.01) were both independent predictors of survival. In subgroup analyses, CTC ≥2 (HR, 8.2; 95% CI: 1.8‐57.5; P < 0.01) and CTC ≥5 (HR, 7.7; 95% CI: 1.4‐42.9; P = 0.02) were both associated with shorter survival among patients with metastasis. There was a trend toward association of CTC ≥5 with shorter survival in patients with nonmetastatic CCA (HR, 4.3; 95% CI: 1.0‐13.8; P = 0.06). CTC ≥2 (HR, 10.5; 95% CI: 2.2‐40.1; P < 0.01) and CTC ≥5 (HR, 10.2; 95% CI: 1.5‐42.3; P = 0.02) were both associated with shorter survival among patients with perihilar/distal CCA. CTC ≥5 was associated with shorter survival of patients with intrahepatic CCA (HR, 4.2; 95% CI: 1.1‐14.1; P = 0.04). Conclusion: CTCs were associated with more‐aggressive tumor characteristics and independently associated with survival in patients with CCA. Assessment of CTCs may be useful for identifying CCA patients at risk of early mortality. (Hepatology 2016;63:148–158)

Abstract Background: Triple negative breast cancer (TNBC) represents 15% of all breast cancers, and is characterized by an aggressive clinical course. While efforts are ongoing to characterize the molecular basis for variation in TNBC, there are conflicting data regarding the impact of prognostic factors such as age and Ki-67 typically used for treatment decisions in other breast cancer subtypes. We identified a retrospective cohort of women with ER- breast cancer with long term follow-up, and performed central confirmation of ER, PR, HER2, Ki-67 and histological classification to assess the association of Ki-67 and histologic subtype on clinical outcome in TNBC pateints (pts). Methods: 9,836 women who underwent breast cancer surgery at Mayo Clinic Rochester from 1985-2005 were identified. Pts were excluded due to: ER+ disease (7363); prior cancer (553); non-invasive disease (465); bilateral breast cancer (167); metastatic disease [at diagnosis or within 60 days of surgery (110)]; ER- disease treated with neoadjuvant chemotherapy (121) or adjuvant hormonal therapy (112); or tumor block exhausted (94). For all others, centralized ER/PR/HER2 identified the following for exclusion, &gt;1% ER staining (n=76), &gt; 1% PR (n=14) and HER2+ (n=144) by IHC (3+) or FISH amplification. 225 cases are still undergoing review. For the centrally confirmed pts with TNBC (n=392), Ki-67 and histological characterization (WHO subtypes) were assessed. Results: Patient characteristics are listed in the table. The median age for all TNBC’s was 45 (range 29-88) and nearly all tumors were grade 3 (91%) with high proliferation (63% with Ki-67 &gt; 30%). The median follow-up was &gt;10 years, where 139 pts had a disease event: progression (86) or second primary (53) and 53 died without a disease event. The 10 yr DFS rate was 55.8% (95%CI: 48.8-63.9%) among the 238 pts who did not receive adjuvant chemotherapy (AdjCT) and 58.9% (95% CI: 48.9-70.9%) among the 102 pts administered AdjCT. In pts without adjCT, DFS was found to differ with respect to number of positive LNs (0 vs. 1-4 vs. 4+; log rank p=0.003) and medullary histology (log rank p=0.015) but not with age (&lt; 50 vs. ≥ 50), tumor size (&lt; 2.0 vs. 2-5 vs. ≥ 5.0 cm) or Ki-67 (0-15% vs. 15.1-30% vs. &gt;30 %). Conclusions: Our findings confirm the poor prognosis of TNBC. The medullary histological subtype is associated with significantly better prognosis than other TNBC subtypes (10 year DFS rate of 78.5%; 95%CI: 59.1-99.9% in pts not treated with adjCT). After central confirmation, neither age nor Ki-67 provide additional prognostic information. Patient characteristicsMedian Age (range)45(29-88) n%Histology Apocrine287.1Carcinoma, anaplastic or undiffrentiated9323.7Central scar/necrotizing348.7Clear Cell297.4Infiltrating ductal ca7118.1Large Cell neuroendocrine143.6Medullary and atypical medullary4311.0Metaplastic ca246.1Trabecular ca338.4other histologies235.9Grade 130.82317.9335891.3Tumor Size 0.1-2 cm19650&gt; 2.0 cm19549.6not stated10.3Nodal status 0251641-38220.94-9338.410+225.6not evaluated41.0Ki-67 0-157719.615.1-306516.6&gt;30%24763.3not done20.5Adjuvant Chemotherapy Yes10226.0No23860.7unknown5213.3 Citation Format: Ahmed Elkhanany, Vera J Suman, Victoria Cafourek, Judith A Gilbert, James N Ingle, Fergus Couch, Daniel W Vissscher, Matthew P Goetz. Triple negative breast cancer: The role of classic histological and prognostic factors on disease free survival [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P5-02-11.

Abstract Targeted BRAF inhibition in melanoma yields frequent and dramatic responses, which are unfortunately followed by almost universal development of therapeutic resistance. In contrast to MAP kinase pathway activation, (e.g., differential BRAF splicing, MEK1 mutations), direct gatekeeper mutations, seen with other targeted therapies, have not yet been reported in association with resistance to targeted BRAF inhibition. Through a combination of genomic profiling of clonal diversity and molecular modeling, we documented a new molecular mechanism of vemurafenib resistance in a melanoma patient, occurring by selection of a pre-existing clonal subpopulation harboring a novel mutation in the vemurafenib-binding site of BRAF. We assessed melanoma clonal diversity using a novel approach for studying tumor heterogeneity in solid tumors, based on separating cellular subpopulations by nuclear flow sorting coupled to next generation sequencing. This approach identified distinct, coexisting melanoma subpopulations prior to initiation of vemurafenib. While vemurafenib treatment suppressed multiple clonal populations, a distinct population was noted at the time of relapse, harboring both the common activating V600E and a novel L567V mutation in the vemurafenib-binding site. Molecular modeling predicted that L567V would interfere with drug binding leading to decreased therapeutic response. Using a lentiviral expression system we assessed the functional effects of the L567V mutation both alone, and in combination with V600E. Assessment of the kinase activity in an in vitro kinase assay using MEK as a substrate indicates that the L567V mutant retains kinase activity. However, expression in a panel of melanoma cell lines demonstrates that while both the V600E single mutant and the L567V single mutant respond to BRAF inhibition by decreasing the levels of phospho-Erk, the double mutant actually responds to treatment by increasing phospho-Erk levels. This is also reflected in the increased viability of cells expressing double mutant in presence of increasing drug levels (PLX4720), compared to either of the single mutants. Taken together, the data suggest that the BRAF L567V/V600E double mutant confers insensitivity to vemurafenib, and that patients harboring both mutations may demonstrate clinically significant resistance to vemurafenib. Further, this data illustrates the role of clonal heterogeneity in mediating key clinical events including response to therapy and development of resistance, a major challenge of targeted BRAF therapies. Citation Format: Aleksandar Sekulic, Ashani T. Weeraratna, Jefferey L. MacKeigan, Amanpreet Kaur, Michael O'Connell, Megan L. Goodall, Michael Barrett, Elizabeth Lenkiewitz, Tara Holley, Victoria Zismann, Michael Gordon, Gideon Bollag, Chao Zhang, Jeffrey M. Trent. Discovery and molecular modeling of a novel mutation in the vemurafenib binding site of BRAF associated with therapeutic resistance in a patient with metastatic melanoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr LB-213. doi:10.1158/1538-7445.AM2014-LB-213

Abstract Small Cell Carcinoma of the Ovary Hypercalcemic Type (SCCOHT) is a rare and highly aggressive malignancy that affects children and young women at a mean age of 24 (range 14 months - 58 years). SCCOHT is refractory to standard of care therapy for ovarian cancer, with ∼75% mortality within 18 months of diagnosis. The early age of onset of SCCOHT and reports of familial occurrence in some cases, strongly suggest an underlying hereditary etiology. To understand the molecular pathogenesis of SCCOHT, we performed next-generation genomic sequencing on a series of tumor and germline samples from SCCOHT patients. This analysis revealed germline and somatic inactivating mutations in SMARCA4, a subunit of the SWI/SNF chromatin-remodeling complex, in 75% (9/12) of SCCOHT patients. Moreover, immunohistochemical (IHC) analysis of 15 tumors revealed that 87% (13/15) of tumors lacked SMARCA4 protein. The high prevalence of SMARCA4 mutations in SCCOHT has not been previously reported in other, more common ovarian carcinomas. We therefore examined the expression of SMARCA4 protein in 300 ovarian carcinomas of different histologies by IHC and found SMARCA4 protein loss in only 6 tumors. In addition, the BIN-67 SCCOHT cell line, which harbors 2 splice site mutations in SMARCA4, showed complete absence of SMARCA4 protein by Western blot while representative cell lines from 4 other ovarian carcinoma subtypes as well as immortalized granulosa cells (SVOG) and adult granulosa tumor cells (KGN) all maintained SMARCA4 expression. The prevalence of germline and sporadic SMARCA4 mutations as well as frequent SMARCA4 protein loss in SCCOHTs implicates this gene as a tumor suppressor in this cancer and more broadly suggests a role for the SWI/SNF complex in its pathogenesis. In addition to providing evidence to the pathogenesis of SCCOHT, this finding provides the opportunity to develop treatment approaches for SCCOHT based on targeting vulnerabilities of SMARCA4-deficient cells. Citation Format: Pilar Ramos, Anthony Karnezis, David Craig, Aleksandar Sekulic, Megan Russell, William Hendricks, Michael Barrett, Karey Shumansky, Yidong Yang, Sohrab Shah, Leah Prentice, Marco Marra, Jeffrey Kiefer, Victoria Zismann, Troy McEachron, Bodour Salhia, Joseph Pressey, John Farley, Stephen Anthony, Richard Roden, Heather Cunliffe, David Huntsman, Jeffrey Trent. The rare, highly malignant small cell carcinoma of the ovary displays common inactivating germline and somatic mutations in the tumor suppressor SMARCA4. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr LB-202. doi:10.1158/1538-7445.AM2014-LB-202

Abstract Despite remarkable therapeutic advances in malignant melanoma, an incomplete understanding of melanoma's extraordinary genetic diversity, complex disease course and ability to resist treatment continues to impede rational, curative clinical intervention. This is particularly true for the understudied “dark matter” of the melanoma genome, i.e. cases that lack mutations in the three most commonly-mutated melanoma genes (BRAF, NRAS, NF1) and that display extensive mutational heterogeneity. Clearly a pressing need exists for transformative approaches to melanoma medicine. We have therefore broadened our traditional focus on melanoma in human patients to include canine melanoma as a model of human disease. Given canine melanoma's clinicopathological resemblance to human non-cutaneous triple-negative subtypes, study of this disease in each species may inform the other. Further, the accelerated clinical course of canine melanoma and flexibility in veterinary clinical trial design may allow for evaluation of novel treatment designs that would not be possible in human cancer trials. Thus, we have undertaken a first-in-dog genomic characterization study of canine melanomas from a cohort of 37 dogs to further explore the landscape of this comparative model. This analysis combines comprehensive genomics (whole genome, whole genome long-insert, RNA sequencing, and array comparative genomic hybridization) in 7 matched canine melanoma/normal tissues with targeted analysis in an additional 27 tumors and 3 cell lines. These canine tumors display striking patterns of mutation and subtype heterogeneity resembling that of their non-cutaneous human counterparts with the majority being BRAF, NRAS, and NF1 wild type and lacking recurrent single nucleotide variants. Despite heterogeneity at the single nucleotide level, shared patterns of structural variation and gene expression exist and these patterns suggest core pathways that may define therapeutic vulnerabilities in these disease subtypes. These data provide the genomic framework for further clinical pursuit of melanoma in the canine model as a paradigm for drug development. Citation Format: William P. Hendricks, Victoria Zismann, Berry Button, Christophe Legendre, Waibhav Tembe, Holly Yin, Michael Bittner, Donald Berry, Matthew Huentelman, Chand Khanna, Patricia LoRusso, Matthew Breen, Aleksandar Sekulic, Jeffrey Trent. The genomic landscape of canine melanoma reveals broad mutational heterogeneity and recurrent patterns of structural variation. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3417. doi:10.1158/1538-7445.AM2014-3417