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Dive into the research topics where Aaron M. Udager is active.

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Featured researches published by Aaron M. Udager.


Blood | 2008

The PHD fingers of MLL block MLL fusion protein-mediated transformation.

Andrew G. Muntean; Diane Giannola; Aaron M. Udager; Jay L. Hess

Chromosomal translocations involving the mixed lineage leukemia (MLL) gene are associated with aggressive acute lymphoid and myeloid leukemias. These translocations are restricted to an 8.3-kb breakpoint region resulting in fusion of amino terminal MLL sequences in frame to 1 of more than 60 different translocation partners. The translocations consistently delete the plant homeodomain (PHD) fingers and more carboxyl terminal MLL sequences. The function of the PHD fingers is obscure and their specific role in transformation has not been explored. Here we show that inclusion of the PHD fingers in the MLL fusion protein MLL-AF9 blocked immortalization of hematopoietic progenitors. Inclusion of 2 or more PHD fingers reduced association with the Hoxa9 locus and suppressed Hoxa9 up-regulation in hematopoietic progenitors. These data provide an explanation for why MLL translocation breakpoints exclude the PHD fingers and suggest a possible role for these domains in regulating the function of wild-type MLL.


Neoplasia | 2014

A Novel RNA In Situ Hybridization Assay for the Long Noncoding RNA SChLAP1 Predicts Poor Clinical Outcome After Radical Prostatectomy in Clinically Localized Prostate Cancer

Rohit Mehra; Yang Shi; Aaron M. Udager; John R. Prensner; Anirban Sahu; Matthew K. Iyer; Javed Siddiqui; Xuhong Cao; John T. Wei; Hui Jiang; Felix Y. Feng; Arul M. Chinnaiyan

Long noncoding RNAs (lncRNAs) are an emerging class of oncogenic molecules implicated in a diverse range of human malignancies. We recently identified SChLAP1 as a novel lncRNA that demonstrates outlier expression in a subset of prostate cancers, promotes tumor cell invasion and metastasis, and associates with lethal disease. Based on these findings, we sought to develop an RNA in situ hybridization (ISH) assay for SChLAP1 to 1) investigate the spectrum of SChLAP1 expression from benign prostatic tissue to metastatic castration-resistant prostate cancer and 2) to determine whether SChLAP1 expression by ISH is associated with outcome after radical prostatectomy in patients with clinically localized disease. The results from our current study demonstrate that SChLAP1 expression increases with prostate cancer progression, and high SChLAP1 expression by ISH is associated with poor outcome after radical prostatectomy in patients with clinically localized prostate cancer by both univariate (hazard ratio = 2.343, P = .005) and multivariate (hazard ratio = 1.99, P = .032) Cox regression analyses. This study highlights a potential clinical utility for SChLAP1 ISH as a novel tissue-based biomarker assay for outcome prognostication after radical prostatectomy.


Developmental Biology | 2011

Hedgehog signaling controls homeostasis of adult intestinal smooth muscle

William J. Zacharias; Blair B. Madison; Katherine E. Kretovich; Katherine D. Walton; Neil Richards; Aaron M. Udager; Xing Li; Deborah L. Gumucio

The Hedgehog (Hh) pathway plays multiple patterning roles during development of the mammalian gastrointestinal tract, but its role in adult gut function has not been extensively examined. Here we show that chronic reduction in the combined epithelial Indian (Ihh) and Sonic (Shh) hedgehog signal leads to mislocalization of intestinal subepithelial myofibroblasts, loss of smooth muscle in villus cores and muscularis mucosa as well as crypt hyperplasia. In contrast, chronic over-expression of Ihh in the intestinal epithelium leads to progressive expansion of villus smooth muscle, but does not result in reduced epithelial proliferation. Together, these mouse models show that smooth muscle populations in the adult intestinal lamina propria are highly sensitive to the level of Hh ligand. We demonstrate further that Hh ligand drives smooth muscle differentiation in primary intestinal mesenchyme cultures and that cell-autonomous Hh signal transduction in C3H10T1/2 cells activates the smooth muscle master regulator Myocardin (Myocd) and induces smooth muscle differentiation. The rapid kinetics of Myocd activation by Hh ligands as well as the presence of an unusual concentration of Gli sties in this gene suggest that regulation of Myocd by Hh might be direct. Thus, these data indicate that Hh is a critical regulator of adult intestinal smooth muscle homeostasis and suggest an important link between Hh signaling and Myocd activation. Moreover, the data support the idea that lowered Hh signals promote crypt expansion and increased epithelial cell proliferation, but indicate that chronically increased Hh ligand levels do not dampen crypt proliferation as previously proposed.


Developmental Dynamics | 2009

Dynamic patterning at the pylorus: formation of an epithelial intestine-stomach boundary in late fetal life.

Xing Li; Aaron M. Udager; Chunbo Hu; Xiaotan T. Qiao; Neil Richards; Deborah L. Gumucio

In the adult mouse, distinct morphological and transcriptional differences separate stomach from intestinal epithelium. Remarkably, the epithelial boundary between these two organs is literally one cell thick. This discrete junction is established suddenly and precisely at embryonic day (E) 16.5, by sharpening a previously diffuse intermediate zone. In the present study, we define the dynamic transcriptome of stomach, pylorus, and intestinal tissues between E14.5 and E16.5. We show that establishment of this boundary is concomitant with the induction of over a thousand genes in intestinal epithelium, and these gene products provide intestinal character. Hence, we call this process intestinalization. We identify specific transcription factors (Hnf4γ, Creb3l3, and Tcfec) and examine signaling pathways (Hedgehog and Wnt) that may play a role in this process. Finally, we define a unique expression domain at the pylorus itself and detect novel pylorus‐specific patterns for the transcription factor Gata3 and the secreted protein nephrocan. Developmental Dynamics 238:3205–3217, 2009.


European Urology | 2016

Overexpression of the Long Non-coding RNA SChLAP1 Independently Predicts Lethal Prostate Cancer

Rohit Mehra; Aaron M. Udager; Thomas U. Ahearn; Xuhong Cao; Felix Y. Feng; Massimo Loda; Joshua Petimar; Philip W. Kantoff; Lorelei A. Mucci; Arul M. Chinnaiyan

The long noncoding RNA SChLAP1 is overexpressed in a subset of prostate cancers (PCa), and high SChLAP1 expression by in situ hybridization (ISH) independently predicts biochemical recurrence after radical prostatectomy. Importantly, although biochemical recurrence is a significant clinical outcome, it is not a validated surrogate for PCa-related mortality. Thus, we evaluated the association between SChLAP1 expression and development of lethal PCa in a large cohort of American men with PCa and long-term follow-up. SChLAP1 ISH was performed on tissue microarrays containing representative formalin-fixed, paraffin-embedded PCa tissue from all patients and scored using a semiquantitative method (ISH score range 0-400). Hazard ratios (HRs) for the association between SChLAP1 expression and time to development of lethal PCa were estimated using multivariable Cox regression analysis. Of the 937 patients evaluated, 89 (9.5%) had high SChLAP1 expression (ISH score ≥100), which in patients treated with radical prostatectomy was strongly associated with development of lethal PCa independent of age, Gleason score, pathologic stage, and PTEN status (HR 2.2, 95% confidence interval 1.1-4.1). These results suggest that SChLAP1 may be a useful tissue-based biomarker for identifying PCa patients at higher risk of lethal progression. PATIENT SUMMARY We examined expression of the RNA molecule SChLAP1 in a large group of prostate cancer patients with long-term follow-up and found that patients with high SChLAP1 expression had a significantly higher chance of developing lethal disease.


Annals of Oncology | 2016

Frequent PD-L1 expression in primary and metastatic penile squamous cell carcinoma: potential opportunities for immunotherapeutic approaches

Aaron M. Udager; Tzu-Ying Liu; Stephanie L. Skala; Martin J. Magers; Andrew S. McDaniel; Daniel E. Spratt; Felix Y. Feng; Javed Siddiqui; Xuhong Cao; Kristina Fields; Todd M. Morgan; Ganesh S. Palapattu; Alon Z. Weizer; Arul M. Chinnaiyan; Ajjai Alva; Jeffery S. Montgomery; Scott A. Tomlins; Hui Jiang; Rohit Mehra

BACKGROUND Despite aggressive multimodal therapy, locally advanced and/or metastatic penile squamous cell carcinoma (SqCC) is associated with significant morbidity and mortality, indicating a need for new therapeutic options. Given the emerging clinical utility of immunotherapeutics, we sought to assess the incidence and potential clinical significance of PD-L1 expression in penile SqCC. PATIENTS AND METHODS Using an anti-PD-L1 primary antibody (clone 5H1), immunohistochemistry was carried out on whole tumor sections from 37 patients with penile SqCC treated at our institution between 2005 and 2013. PD-L1-positive tumors were defined as those with membranous staining in ≥5% of tumor cells. Association between PD-L1 expression and clinicopathologic parameters was examined using Fishers exact test. Correlation between PD-L1 expression in primary tumors and matched metastases was assessed using the Spearman rank correlation coefficient (ρ). The difference in cancer-specific mortality between PD-L1-positive and -negative groups was examined using the log-rank test. RESULTS Twenty-three (62.2%) of 37 primary tumors were positive for PD-L1 expression, and there was strong positive correlation of PD-L1 expression in primary and metastatic samples (ρ = 0.72; 0.032 < P < 0.036). Primary tumor PD-L1 expression was significantly associated with usual type histology (P = 0.040) and regional lymph node metastasis (P = 0.024), as well as decreased cancer-specific survival (P = 0.011). CONCLUSIONS The majority of primary penile SqCC tumors express PD-L1, which is associated with high-risk clinicopathologic features and poor clinical outcome. These data provide a rational basis for further investigation of anti-PD-1 and anti-PD-L1 immunotherapeutics in patients with advanced penile SqCC.


The American Journal of Surgical Pathology | 2014

Hereditary leiomyomatosis and renal cell carcinoma (HLRCC): a rapid autopsy report of metastatic renal cell carcinoma.

Aaron M. Udager; Ajjai Alva; Ying Bei Chen; Javed Siddiqui; Amir Lagstein; Satish K. Tickoo; Victor E. Reuter; Arul M. Chinnaiyian; Rohit Mehra

Rapid (“warm”) autopsies of patients with advanced metastatic cancer provide invaluable insight into the natural history, pathobiology, and morphology of advanced and treatment-resistant tumors. Here, we report a rapid autopsy case of a hereditary leiomyomatosis and renal cell carcinoma (HLRCC) patient with advanced metastatic renal cell carcinoma (RCC)—the first such case described for either a primary renal tumor or HLRCC-related cancer. Mutations in the fumarate hydratase (FH) gene underlie HLRCC, a rare syndrome involving cutaneous and uterine leiomyomata and aggressive kidney tumors. Loss of heterozygosity at the wild-type FH gene locus results in profound cellular metabolic derangement, “pseudohypoxic” upregulation of hypoxia-inducible factor 1&agr; (HIF-1&agr;)-dependent transcription, and aberrant protein succination; these molecular changes drive oncogenesis of kidney tumors in HLRCC patients. The current index patient had a high-grade RCC with classic morphologic features of HLRCC, including large nuclei with prominent eosinophilic nucleoli and perinucleolar clearing. In addition, this patient’s RCC demonstrated extensive sarcomatoid and rhabdoid features—morphologies not previously well described in HLRCC-associated kidney tumors. Here, we report the extent of metastatic dissemination and supplement this unique tumor morphology with mitochondrial enzyme histochemistry and extended immunohistochemical analysis. Tumor cells strongly expressed PAX8, vimentin, CD10, and the HIF target GLUT1 and showed increased nuclear p53 accumulation; the expression of other RCC markers was negative. We also detail microscopic tubular epithelial changes in the grossly uninvolved ipsilateral renal parenchyma and demonstrate sporadic, aberrant upregulation of the HIF targets GLUT1 and CAIX in dysplastic peritumoral tubules.


The Prostate | 2014

Frequent discordance between ERG gene rearrangement and ERG protein expression in a rapid autopsy cohort of patients with lethal, metastatic, castration-resistant prostate cancer.

Aaron M. Udager; Yang Shi; Scott A. Tomlins; Ajjai Alva; Javed Siddiqui; Xuhong Cao; Kenneth J. Pienta; Hui Jiang; Arul M. Chinnaiyan; Rohit Mehra

ERG rearrangements in localized prostate cancer can be detected with high sensitivity and specificity by immunohistochemistry (IHC). However, recent data suggest that ERG IHC may be less sensitive for ERG rearrangements in castration‐resistant prostate cancer (CRPC). Thus, we sought to examine ERG protein expression in a cohort of rapid autopsy patients with lethal metastatic CRPC (mCRPC).


Cancer Journal | 2014

Current and proposed molecular diagnostics in a genitourinary service line laboratory at a tertiary clinical institution.

Aaron M. Udager; Ajjai Alva; Rohit Mehra

AbstractThe idea that detailed knowledge of molecular oncogenesis will drive diagnostic, prognostic, and therapeutic clinical decision making in an increasingly multidisciplinary practice of oncologic care has been anticipated for many years. With the recent rapid advancement in our understanding of the molecular underpinnings of genitourinary malignancies, this concept is now starting to take shape in the fields of prostate, kidney, bladder, testicular, and penile cancer. Such breakthroughs necessitate the development of robust clinical-grade assays that can be quickly made available for patients to facilitate diagnosis in challenging cases, risk-stratify patients for subsequent clinical management, select the appropriate targeted therapy from among increasingly diverse and numerous options, and enroll patients in advanced clinical trials. This rapid translation of basic and clinical cancer research requires a streamlined, multidisciplinary approach to clinical assay development, termed here the molecular diagnostics service line laboratory. In this review, we summarize the current state and explore the future of molecular diagnostics in genitourinary oncology to conceptualize a genitourinary service line laboratory at a tertiary clinical institution.


American Journal of Pathology | 2014

Primary urethral clear-cell adenocarcinoma: comprehensive analysis by surgical pathology, cytopathology, and next-generation sequencing.

Rohit Mehra; Pankaj Vats; Shanker Kalyana-Sundaram; Aaron M. Udager; Michael Roh; Ajjai Alva; Jincheng Pan; Robert J. Lonigro; Javed Siddiqui; Alon Z. Weizer; Cheryl T. Lee; Xuhong Cao; Yi Mi Wu; Dan R. Robinson; Saravana M. Dhanasekaran; Arul M. Chinnaiyan

Primary clear-cell adenocarcinoma of the urethra, a rare tumor that histomorphologically resembles clear-cell carcinoma of the female genital tract, occurs predominantly in women and is associated with a relatively poor prognosis. The histogenesis of this rare urethral neoplasm has not been completely resolved, but it is thought to arise from either müllerian rests or metaplastic urothelium. Herein, we present comprehensive surgical pathological and cytopathological findings from a patient with primary urethral clear-cell adenocarcinoma and describe next-generation sequencing results for this patients unique tumor-the first such reported characterization of molecular aberrations in urethral clear-cell adenocarcinoma at the transcriptomic and genomic levels. Transcriptome analysis revealed novel gene fusion candidates, including ANKRD28-FNDC3B. Whole-exome analysis demonstrated focal copy number loss at the SMAD4 and ARID2 loci and 38 somatic mutations, including a truncating mutation in ATM and a novel nonsynonymous mutation in ALK.

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Rohit Mehra

University of Michigan

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