Aejaz Nasir

Efficacy and Safety of Abemaciclib, an Inhibitor of CDK4 and CDK6, for Patients with Breast Cancer, Non-Small Cell Lung Cancer, and Other Solid Tumors.

UNLABELLEDnWe evaluated the safety, pharmacokinetic profile, pharmacodynamic effects, and antitumor activity of abemaciclib, an orally bioavailable inhibitor of cyclin-dependent kinases (CDK) 4 and 6, in a multicenter study including phase I dose escalation followed by tumor-specific cohorts for breast cancer, non-small cell lung cancer (NSCLC), glioblastoma, melanoma, and colorectal cancer. A total of 225 patients were enrolled: 33 in dose escalation and 192 in tumor-specific cohorts. Dose-limiting toxicity was grade 3 fatigue. The maximum tolerated dose was 200 mg every 12 hours. The most common possibly related treatment-emergent adverse events involved fatigue and the gastrointestinal, renal, or hematopoietic systems. Plasma concentrations increased with dose, and pharmacodynamic effects were observed in proliferating keratinocytes and tumors. Radiographic responses were achieved in previously treated patients with breast cancer, NSCLC, and melanoma. For hormone receptor-positive breast cancer, the overall response rate was 31%; moreover, 61% of patients achieved either response or stable disease lasting ≥6 months.nnnSIGNIFICANCEnAbemaciclib represents the first selective inhibitor of CDK4 and CDK6 with a safety profile allowing continuous dosing to achieve sustained target inhibition. This first-in-human experience demonstrates single-agent activity for patients with advanced breast cancer, NSCLC, and other solid tumors. Cancer Discov; 6(7); 740-53. ©2016 AACR.See related commentary by Lim et al., p. 697This article is highlighted in the In This Issue feature, p. 681.

A Phase 1 Dose Escalation, Pharmacokinetic, and Pharmacodynamic Evaluation of eIF-4E Antisense Oligonucleotide LY2275796 in Patients with Advanced Cancer

Purpose: The antisense oligonucleotide LY2275796 blocks expression of cap-binding protein eukaryotic initiation factor 4E (eIF-4E), an mRNA translation regulator upregulated in tumors. This phase I study sought an appropriate LY2275796 dose in patients with advanced tumors. Experimental Design: A 3-day loading dose, then weekly maintenance doses, were given to 1 to 3 patient cohorts, beginning with 100 mg and escalating. Plasma samples were collected to determine LY2275796 concentrations and tumor biopsies to quantify eIF-4E mRNA/protein. Results: Thirty patients with stage 4 disease received 1 or more LY2275796 dose. A dose-limiting toxicity was observed at 1,200 mg, with 1,000 mg the maximum-tolerated dose. Across all dose levels, most patients (87%) had only grade 1 to 2 toxicities. LY2275796 pharmacokinetics supported the dosing regimen. Comparison of pre- and postdose biopsies showed eIF-4E decreased in most patients. Fifteen patients had progressive disease, and 7 patients achieved stable disease (minimum of 6 weeks) as best response, with 2 patients on therapy for more than 3 months (one with melanoma, one with cystadenocarcinoma of the head/neck). Conclusions: LY2275796 was well tolerated up to 1,000 mg. Because tumor eIF-4E expression was decreased, but no tumor response observed, LY2275796 should be studied combined with other treatment modalities. Clin Cancer Res; 17(20); 6582–91. ©2011 AACR.

Tumor Cell Expression of Vascular Endothelial Growth Factor Receptor 2 Is an Adverse Prognostic Factor in Patients with Squamous Cell Carcinoma of the Lung

A robust immunohistochemical (IHC) assay for VEGFR2 was developed to investigate its utility for patient tailoring in clinical trials. The sensitivity, specificity, and selectivity of the IHC assay were established by siRNA knockdown, immunoblotting, mass spectrometry, and pre-absorption experiments. Characterization of the assay included screening a panel of multiple human cancer tissues and an independent cohort of non-small cell lung carcinoma (NSCLC, nu200a=u200a118) characterized by TTF-1, p63, CK5/6, and CK7 IHC. VEGFR2 immunoreactivity was interpreted qualitatively (VEGFR2 positive/negative) in blood vessels and by semi-quantitative evaluation using H-scores in tumor cells (0–300). Associations were determined among combinations of VEGFR2 expression in blood vessels and tumor cells, and clinico-pathologic characteristics (age, sex, race, histologic subtype, disease stage) and overall survival using Kaplan-Meier analyses and appropriate statistical models. VEGFR2 expression both in blood vessels and in tumor cells in carcinomas of the lung, cervix, larynx, breast, and others was demonstrated. In the validation cohort, 99/118 (83.9%) NSCLC tissues expressed VEGFR2 in the blood vessels and 46/118 (39.0%) showed high tumor cell positivity (H-score ≥10). Vascular and tumor cell expression were inversely correlated (pu200a=u200a0.0175). High tumor cell expression of VEGFR2 was associated with a 3.7-fold reduction in median overall survival in lung squamous-cell carcinoma (SCC, nu200a=u200a25, pu200a=u200a0.0134). The inverse correlation between vascular and tumor cell expression of VEGFR2 and the adverse prognosis associated with high VEGFR2 expression in immunohistochemically characterized pulmonary SCC are new findings with potential therapeutic implications. The robustness of this novel IHC assay will support further evaluation of its utility for patient tailoring in clinical trials of antiangiogenic agents.

Neuroendocrine Neoplasms of the Colon and Rectum

Neuroendocrine neoplasms of the colon and rectum are derived from the same stem cell which gives rise to glandular cells and other cells lining the epithelium. Neuroendocrine carcinomas are more common in the colon, whereas neuroendocrine tumors are more common in the rectum. In the colon neuroendocrine carcinomas can be seen mixed with other types of tumors including adenocarcinomas. These tumors are mainly nonfunctional, but the neuroendocrine tumors in the cecum and right colon which composed of EC cells can be functional and in rare cases can cause carcinoid syndrome. These neoplasms share some of the molecular changes that are seen in these neoplasms in other parts of the GI system.

Stromal-Based Signatures for the Classification of Gastric Cancer

Treatment of metastatic gastric cancer typically involves chemotherapy and monoclonal antibodies targeting HER2 (ERBB2) and VEGFR2 (KDR). However, reliable methods to identify patients who would benefit most from a combination of treatment modalities targeting the tumor stroma, including new immunotherapy approaches, are still lacking. Therefore, we integrated a mouse model of stromal activation and gastric cancer genomic information to identify gene expression signatures that may inform treatment strategies. We generated a mouse model in which VEGF-A is expressed via adenovirus, enabling a stromal response marked by immune infiltration and angiogenesis at the injection site, and identified distinct stromal gene expression signatures. With these data, we designed multiplexed IHC assays that were applied to human primary gastric tumors and classified each tumor to a dominant stromal phenotype representative of the vascular and immune diversity found in gastric cancer. We also refined the stromal gene signatures and explored their relation to the dominant patient phenotypes identified by recent large-scale studies of gastric cancer genomics (The Cancer Genome Atlas and Asian Cancer Research Group), revealing four distinct stromal phenotypes. Collectively, these findings suggest that a genomics-based systems approach focused on the tumor stroma can be used to discover putative predictive biomarkers of treatment response, especially to antiangiogenesis agents and immunotherapy, thus offering an opportunity to improve patient stratification. Cancer Res; 76(9); 2573-86. ©2016 AACR.

Neuroendocrine Neoplasms of the Appendix

Primary neoplasms of the appendix showing neuroendocrine differentiation include neuroendocrine tumors (NETs), neuroendocrine carcinomas (NECs), and mixed adenoneuroendocrine carcinomas (MANECs), including goblet cell carcinoids. NETs comprise 50–77 % of all appendiceal neoplasms and 19 % of all gastrointestinal (GI) NETs. Primary NECs of the appendix are extremely rare and exhibit immunohistopathologic profile similar to NECs at other sites within the GI tract. MANECs arise from a pre-existing goblet cell carcinoid (GCC) and consist of a mixture of exocrine (signet ring type or poorly differentiated) and endocrine carcinoma components, with one component exceeding 30 %. Appendiceal NETs are more frequent in females, and most are diagnosed incidentally in the distal third (75 %) of the appendix. Mean age at presentation is 32–43 years; tubular NETs occur at younger age compared to goblet cell carcinoids. Most appendiceal neoplasms are clinically silent or may simulate acute appendicitis with intermittent abdominal pain or pain localized in the right lower abdomen. Carcinoid syndrome is rare and suggests extensive metastatic disease. Most appendiceal NETs are enterochromaffin cell (EC cell) serotonin-producing neoplasms. Less frequent subtypes include L cell NETs and tubular carcinoids. The latter can be misdiagnosed as metastatic adenocarcinoma as it lacks direct contact with the appendiceal mucosa. GCCs are relatively rare, while primary NECs, or MANECs, are extremely rare, but can pose diagnostic challenges for practicing pathologists and need careful sampling, review, and workup. The vast majority of patients with NETs of the appendix have favorable prognosis, with 88–94 % 5-year survival for localized disease and 25–31 % with distant metastatic disease. Prognosis of GCC is intermediate between carcinoids and appendiceal adenocarcinomas with an overall 5-year survival of 76 %. Since patients with appendiceal NETs are at increased risk for other GI malignancies, follow-up with colonoscopic screening is warranted.

Neuroendocrine Neoplasms of the Stomach

Based on rising incidence in recent decades, gastric neuroendocrine tumors (G-NETs) or gastric carcinoids (GCs) are being increasingly identified at endoscopy, both as polypoid and nonpolypoid gastric lesions. There are four types of G-NETs with important epidemiological, pathophysiological, histopathologic, and endoscopic differences that affect their diagnosis, prognosis, and patient management. The underlying pathogenetic mechanism, hypergastrinemia, results from achlorhydria in patients with chronic atrophic gastritis (type I G-NETs) and from gastrinoma in patients with MEN1 (multiple endocrine neoplasia type I) syndrome (type II G-NETs). Both ECL-cell dysplasia and severe hyperplasia increase risk for G-NET development in type A chronic atrophic gastritis with hypergastrinemia/G-cell hyperplasia. Type III G-NETs occur sporadically, independent of gastrin levels. The histologic typing, grading, and Ki67 index are important for prognostication and patient management. Type I G-NETs 1 cm should be resected due to small risk of lymph node metastases. Both type I G-NETs >1 cm and type II G-NETs should be evaluated for invasion beyond the submucosa prior to endoscopic resection. Type III G-NETs should be managed similar to gastric adenocarcinoma. The treatment of advanced G-NETs needs to be multimodal and best accomplished in subspecialty referral centers with advanced clinical, pathologic, and imaging expertise. In order to succeed with more personalized patient management strategies, analytical and clinical validation of relevant biomarkers will be critical in the near future.

Differential expression of VEGFR2 protein in HER2 positive primary human breast cancer: potential relevance to anti-angiogenic therapies

BackgroundClinically relevant predictive biomarkers to tailor anti-angiogenic therapies to breast cancer (BRC) patient subpopulations are an unmet need.MethodsWe analyzed tumor vascular density and VEGFR2 protein expression in various subsets of primary human BRCs (186 females; Mean age: 59xa0years; range 33–88xa0years), using a tissue microarray. Discrete VEGFR2+xa0and CD34+xa0tumor vessels were manually scored in invasive ductal, lobular, mixed ductal-lobular and colloid (Nxa0=xa0139, 22, 18, 7) BRC cores.ResultsThe observed CD34+xa0and VEGFR2+xa0tumor vascular counts in individual cases were heterogeneous. Mean CD34+xa0and VEGFR2+xa0tumor vessel counts were 11 and 3.4 per tumor TMA core respectively. Eighty-nine of 186 (48%) cases hadxa0>10 CD34+xa0tumor vessels, while 97/186 (52%) had fewer CD34+xa0vessels in each TMA core. Of 169 analyzable cores in the VEGFR2 stained TMA, 90 (53%) showed 1–5 VEGFR2+xa0tumor vessels/TMA core, while 42/169 (25%) cores had no detectable VEGFR2+xa0tumor vessels. Thirteen of 169 (8%) cases also showed tumor cell (cytoplasmic/membrane) expression of VEGFR2. Triple-negative breast cancers (TNBCs) appeared to be less vascular (Mean VDxa0=xa09.8, range 0–34) than other breast cancer subtypes. Overall, VEGFR2+xa0tumor vessel counts were significantly higher in HER2+xa0as compared to HR+xa0(pxa0=xa00.04) and TNBC (pxa0=xa00.02) tissues. Compared to HER2− cases, HER2+xa0breast cancers had higher VEGFR2+xa0tumor vessel counts (pxa0=xa00.007).ConclusionCharacterization of pathologic angiogenesis in HER2+xa0breast cancer provides scientific rationale for future investigation of clinical activity of agents targeting the VEGF/VEGFR2 axis in this clinically aggressive breast cancer subtype.

Breast Carcinomas with Neuroendocrine Features (Neuroendocrine Carcinomas of the Breast)

Breast carcinomas with neuroendocrine features (NEC) have only been recently recognized as a separate diagnostic entity by the World Health Organization classification. This category of tumors encompasses neuroendocrine tumor, well differentiated; neuroendocrine carcinoma, poorly differentiated/small cell carcinoma; and invasive breast carcinoma with neuroendocrine differentiation. Because of the lack of specific clinical or imaging features, diagnosis of NEC depends upon recognition of its histologic growth pattern and immunohistochemical (IHC) staining for neuroendocrine markers. Histologic features that suggest neuroendocrine differentiation include low nuclear grade, palisading of nuclei at the periphery of the tumor, and sparse cellular stroma. A number of diagnostic criteria have been proposed to render this diagnosis. Currently, it is accepted that the tumors should display morphological features similar to neuroendocrine carcinomas of the lung and gastrointestinal (GI) tract and/or should have proven neuroendocrine differentiation using IHC markers. An important issue when diagnosing breast carcinomas with neuroendocrine features is that it is necessary to differentiate them from metastatic neuroendocrine tumors to the breast. This distinction has important clinical implications and will directly impact patient care. In this review, we will highlight the pathological, molecular, and clinical characteristics of NEC in the breast as well as discuss the most current available literature.

Abstract 4175: Robust immunohistochemical assay to characterize human cancer tissues for prevalence of vascular endothelial growth factor receptor 3 (VEGFR3)

VEGFR3 plays a key role in the regulation of lymphangiogenesis in adults, and is also important for tumor angiogenesis and metastasis. In order to characterize human cancer tissues for imunohistochemical (IHC) localization and prevalence of VEGFR3 protein, we developed a robust IHC assay in our lab using a mouse monoclonal primary antibody (Millipore). To optimize the various assay parameters, we utilized high-quality VEGFR3 positive (and internal negative) control tissues (Kaposi9s sarcoma, angiosarcoma, lymph node). Reagent negative controls were satisfactory. Specificity of the primary anti-VEGFR3-antibody was supported by a discrete band at the expected molecular weight on western blots using a VEGFR3 transfected cell lysate and negative control cell lines. We also demonstrated lack of specific vascular VEGFR3 staining in pre-absorption experiments with VEGFR3 (but not VEGFR1 or 2) recombinant protein, supporting selectivity of the primary antibody for VEGFR3. Using the fully optimized assay, we stained a human multi-tumor screening tissue microarray (TMA) to demonstrate full range of specific vascular VEGFR3 staining in glioblastoma and carcinomas of the colon, breast, ovary, pancreas, lung, larynx, kidney, cervix, bladder, extrahepatic cholangiocarcinoma and malignant melanoma. Specific, unequivocal VEGFR3 immunoreactivity was interpreted qualitatively (VEGFR3 positive/negative) in tumor blood and lymphatic vessels. No tumor cell staining was seen. Some colon cancer tissues in multi-tumor TMA were VEGFR3+, while others were VEGFR3-. The observed variation in VEGFR3 expression and vascular distribution on screening TMA were further evaluated in two independent cohorts of well-characterized human colorectal cancer tissues (organ-specific TMAs) by a Board-certified, subspecialty GI pathologist (AN), with overall VEGFR3 prevalence rates of 62% (36 of 58 cases) and 56% (55 of 98 cases). Using CD34 and D2-40 IHC assays from a CLIA-certified lab, we confirmed IHC localization of VEGFR3 protein both in the stromal blood vessels and lymphatics within the invasive colorectal cancer stroma. In conclusion, following well-established IHC assay development and standardization protocols and efficient workflow paradigm, we have used a technically robust IHC assay to characterize routinely processed archival human cancer tissues and have demonstrated specific VEGFR3 expression patterns, tissue localization and prevalence in human colorectal cancer tissues. Based on its performance in our hands, this assay can be used to further evaluate patterns of VEGFR3 expression in areas of tumor angiogenesis in other human cancer tissues. Data-driven hypotheses generated from such investigations will be relevant to corroborate VEGF receptor biology and emerging clinical experience with anti-VEGF/anti-VEGFR therapies. Citation Format: Timothy R. Holzer, Drew M. Nedderman, Aejaz Nasir. Robust immunohistochemical assay to characterize human cancer tissues for prevalence of vascular endothelial growth factor receptor 3 (VEGFR3). [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4175. doi:10.1158/1538-7445.AM2015-4175