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Dive into the research topics where George P. Hemstreet is active.

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Featured researches published by George P. Hemstreet.


Journal of The National Comprehensive Cancer Network | 2016

NCCN Guidelines Insights: Prostate Cancer Early Detection, Version 2.2016

Peter R. Carroll; J. Kellogg Parsons; Gerald L. Andriole; Robert R. Bahnson; Erik P. Castle; William J. Catalona; Douglas M. Dahl; John W. Davis; Jonathan I. Epstein; Ruth Etzioni; Thomas A. Farrington; George P. Hemstreet; Mark H. Kawachi; Simon P. Kim; Paul H. Lange; Kevin R. Loughlin; William T. Lowrance; Paul Maroni; James L. Mohler; Todd M. Morgan; Kelvin A. Moses; Robert B. Nadler; Michael A. Poch; Charles D. Scales; Terrence M. Shaneyfelt; Marc C. Smaldone; Geoffrey A. Sonn; Preston Sprenkle; Andrew J. Vickers; Robert W. Wake

The NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Prostate Cancer Early Detection provide recommendations for prostate cancer screening in healthy men who have elected to participate in an early detection program. The NCCN Guidelines focus on minimizing unnecessary procedures and limiting the detection of indolent disease. These NCCN Guidelines Insights summarize the NCCN Prostate Cancer Early Detection Panels most significant discussions for the 2016 guideline update, which included issues surrounding screening in high-risk populations (ie, African Americans, BRCA1/2 mutation carriers), approaches to refine patient selection for initial and repeat biopsies, and approaches to improve biopsy specificity.


Journal of Cellular Biochemistry | 1999

Alterations of the actin polymerization status as an apoptotic morphological effector in HL-60 cells.

Jianyu Rao; Yu Sheng Jin; QinLong Zheng; Jeanne Cheng; Jennifer Tai; George P. Hemstreet

The alterations of the cytoskeletal actin network have been implicated as a morphological effector in apoptosis. However, studies directly linking actin change to the morphological events in apoptosis are lacking. This study quantitatively examined the effect of actin alteration on the camptothecin (CPT)‐induced apoptotic process in HL‐60 cells. Actin alteration was induced by two distinctive types of agent: the polymerization‐stimulating agent, Jasplakinolide (Jas), and the polymerization‐blocking agent, cytochalasin B (CB). The actin polymerization status was measured by two complementary methods: the cell pellet‐based DNase I inhibition method, and the individual cell‐based quantitative fluorescence image analysis (QFIA) assay. Actin polymerization induced by Jas caused apoptosis directly. By contrast, CB, an actin polymerization‐blocking agent, partially inhibited CPT‐induced apoptosis. A similar inhibition of the CPT‐induced apoptosis response was observed with a more specific actin depolymerization agent, cytochalasin E. The alterations of the actin polymerization status occurred in three sequential steps during the apoptotic process: first polymerization, followed by depolymerization, and finally degradation. However, compared with CPT‐induced apoptosis, Jas‐induced apoptosis was characterized by pronounced actin polymerization that corresponded morphologically with prominent membrane blebbing, but less apoptotic body formation. Furthermore, DNase I activity, which is normally inhibited by G‐actin, was specifically detected in Jas‐treated cells. These results show that the regulation of actin polymerization is an important apoptotic morphological effector, whereas the alterations of the actin polymerization status by chemicals have profound effects not only on altering the morphology of apoptotic cells, but on apoptosis induction in HL‐60 cells as well. J. Cell. Biochem. 75:686–697, 1999.


Biochemical and Biophysical Research Communications | 2003

Protein kinase C μ is down-regulated in androgen-independent prostate cancer

Meena Jaggi; Prema S. Rao; David J. Smith; George P. Hemstreet; K.C. Balaji

Abstract Progression to androgen independence (AI) is the main cause of death in prostate cancer. Our prior differential gene expression studies by microarray analysis in progressive prostate cancer cell line model identified dysregulation of protein kinase C μ (PKCμ) expression in prostate cancer. In this study, quantitative ribonuclease protection assay and immunoblot analysis demonstrate down regulation of PKCμ at transcription and translational level, respectively, in AI C4-2 cells compared to its parental androgen dependent (AD) LNCaP prostate cancer cells. Significantly lower PKCμ kinase activity was confirmed in C4-2 cells by in vitro kinase assay. Immunohistochemical studies of prostate cancer tissue from patient progressing to AI prostate cancer demonstrated that PKCμ expression is decreased in 100% of AI human prostate cancers. The consistent down regulation of PKCμ in cell line models and human prostate cancer tissues suggests a possible functionally significant role for PKCμ in progression to AI in prostate cancer.


Cancer | 1993

Bladder cancer risk assessment with quantitative fluorescence image analysis of tumor markers in exfoliated bladder cells

C.T. Rebecca B. Bonner M.S.; Jian Yu Rao; George P. Hemstreet; Yves Fradet; Kyung Whan Min; Robert E. Hurst

Background. The detection of potentially highly curable low‐grade bladder cancers by noninvasive techniques remains an unsolved problem. Conventional cytology detects such tumors with 50% sensitivity, and addition of DNA measurements to cytology only improves sensitivity incrementally. Tumor‐associated antigens potentially offer an additional diagnostic marker.


Sarcoma | 2010

Clinical features of sarcomatoid carcinoma (carcinosarcoma) of the urinary bladder: analysis of 221 cases.

Jue Wang; Fen Wei Wang; Chad A. LaGrange; George P. Hemstreet; Anne Kessinger

Background. Urinary bladder sarcomatoid carcinoma (carcinosarcoma) is rare. The objective of this study was to examine the epidemiology, natural history, and prognostic factors of urinary bladder carcinosarcoma using population-based registry. Methods. The Surveillance, Epidemiology, and End Results (SEER) Program database was used to identify cases by tumor site and histology codes. The association between clinical and demographic characteristics and long-term survival was examined. Results. A total of 221 histology confirmed cases were identified between 1973 and 2004, this accounted for approximately 0.11% of all primary bladder tumors during the study period. Median age of the patients was 75 years (range 41–96). Of the patients with a known tumor stage (N = 204), 72.5% had a regional or distant stage; 98.4% of patients with known histology grade (N = 127), had poorly or undifferentiated histology. Multiple primary tumors were indentified in about 40% of study subjects. The majority of patients (95.9%) received cancer directed surgery, 35.8% had radical or partial cystectomy, 15.8% of patients received radiation therapy combination with surgery. The median overall survival was 14 months (95% CI 7–21 months). 1-, 5-, and 10-year cancer specific survival rate were 53.9%, 28.4% and 25.8%. In a multivariate analysis, only tumor stage was found to be a significant prognostic factor for disease-specific survival. Conclusions. Urinary bladder carcinosarcoma commonly presented as high grade, advanced stage and aggressive behavior with a poor prognosis. Emphasis on early detection, including identification of risk factors is needed to improve the outcome for patients with this malignancy.


Clinical Cancer Research | 2008

Phase III prevention trial of fenretinide in patients with resected non-muscle-invasive bladder cancer.

Anita L. Sabichi; Seth P. Lerner; E. Neely Atkinson; H. Barton Grossman; Nancy P. Caraway; Colin P. Dinney; David F. Penson; Surena F. Matin; Ashish M. Kamat; Louis L. Pisters; Daniel W. Lin; Ruth L. Katz; Dean E. Brenner; George P. Hemstreet; Mary Wargo; Archie Bleyer; William H. Sanders; John L. Clifford; Howard L. Parnes; Scott M. Lippman

Purpose: The study aims to evaluate the efficacy and toxicity of fenretinide in preventing tumor recurrence in patients with transitional cell carcinoma (TCC) of the bladder. Experimental Design: We conducted a multicenter phase III, randomized, placebo-controlled trial of fenretinide (200 mg/day orally for 12 months) in patients with non–muscle-invasive bladder TCC (stages Ta, Tis, or T1) after transurethral resection with or without adjuvant intravesical Bacillus Calmette-Guerin (BCG). Patients received cystoscopic evaluation and bladder cytology every 3 months during the 1-year on study drug and a final evaluation at 15 months. The primary endpoint was time to recurrence. Results: A total of 149 patients were enrolled; 137 were evaluable for recurrence. The risk of recurrence was considered to be “low” in 72% (no prior BCG) and intermediate or high in 32% (prior BCG) of the evaluable patients. Of the lower-risk group, 68% had solitary tumors and 32% had multifocal, low-grade papillary (Ta, grade 1 or grade 2) tumors. The 1-year recurrence rates by Kaplan-Meier estimate were 32.3% (placebo) versus 31.5% (fenretinide; P = 0.88 log-rank test). Fenretinide was well tolerated and had no unexpected toxic effects; only elevated serum triglyceride levels were significantly more frequent on fenretinide (versus placebo). The Data Safety and Monitoring Board recommended study closure at 149 patients (before reaching the accrual goal of 160 patients) because an interim review of the data showed a low likelihood of detecting a difference between the two arms, even if the original accrual goal was met. Conclusions: Although well tolerated, fenretinide did not reduce the time-to-recurrence in patients with Ta, T1, or Tis TCC of the bladder.


Urologia Internationalis | 2015

Molecular markers for bladder cancer screening, early diagnosis, and surveillance: The WHO/ICUD consensus

Bernd J. Schmitz-Dräger; Michael J. Droller; Vinata B. Lokeshwar; Yair Lotan; M'Liss A. Hudson; Bas W.G. van Rhijn; M. Marberger; Yves Fradet; George P. Hemstreet; Per Malmström; Osamu Ogawa; Pierre I. Karakiewicz; Shahrokh F. Shariat

Due to the lack of disease-specific symptoms, diagnosis and follow-up of bladder cancer has remained a challenge to the urologic community. Cystoscopy, commonly accepted as a gold standard for the detection of bladder cancer, is invasive and relatively expensive, while urine cytology is of limited value specifically in low-grade disease. Over the last decades, numerous molecular assays for the diagnosis of urothelial cancer have been developed and investigated with regard to their clinical use. However, although all of these assays have been shown to have superior sensitivity as compared to urine cytology, none of them has been included in clinical guidelines. The key reason for this situation is that none of the assays has been included into clinical decision-making so far. We reviewed the current status and performance of modern molecular urine tests following systematic analysis of the value and limitations of commercially available assays. Despite considerable advances in recent years, the authors feel that at this stage the added value of molecular markers for the diagnosis of urothelial tumors has not yet been identified. Current data suggest that some of these markers may have the potential to play a role in screening and surveillance of bladder cancer. Well-designed protocols and prospective, controlled trials will be needed to provide the basis to determine whether integration of molecular markers into clinical decision-making will be of value in the future.


The Journal of Urology | 1991

Identification of a High Risk Subgroup of Grade 1 Transitional Cell Carcinoma Using Image Analysis Based Deoxyribonucleic Acid Ploidy Analysis of Tumor Tissue

George P. Hemstreet; Scott Rollins; Philip Jones; Jianyu Rao; Robert E. Hurst; Rebecca B. Bonner; Tommy Hewett; Bobby G. Smith

The use of deoxyribonucleic acid (DNA) cytometry to identify a subset of patients with grade 1, stage Ta or T1 transitional cell carcinoma at high risk for death or recurrence was investigated in a retrospective study using paraffin blocks from 88 low grade transitional cell carcinomas of the bladder with an absorptiometric video-based image analysis system. Tumors were evaluated for ploidy (70 diploid, 16 aneuploid and 2 tetraploid) and the presence of cells with greater than 5C DNA. Survival analysis of 62 patients with adequate followup (15 to 20 years) showed that 43 of 62 (69%) suffered recurrences and 13 (21%) died of bladder cancer. The single most important predictors of death and recurrence were stem line aneuploidy and the presence of cells with greater than 5C DNA, respectively.


Cancer | 2000

Loss of tissue transglutaminase as a biomarker for prostate adenocarcinoma

Paul J. Birckbichler; Rebecca B. Bonner; Robert E. Hurst; Barbara L. Bane; Jan V. Pitha; George P. Hemstreet

Additional molecular tissue biomarkers for prostate carcinoma are needed to stratify patients with clinically suspicious findings, such as an elevated prostate specific antigen (PSA) with a negative biopsy, according to risk.


International Journal of Cancer | 2006

NAT2 slow acetylation and bladder cancer in workers exposed to benzidine

Tania Carreón; Avima M. Ruder; Paul A. Schulte; Richard B. Hayes; Nathaniel Rothman; Martha A. Waters; Delores J. Grant; Robert Boissy; Douglas A. Bell; Fred F. Kadlubar; George P. Hemstreet; Songnian Yin; Grace K. LeMasters

This study expands a previous study of NAT2 polymorphisms and bladder cancer in male subjects occupationally exposed only to benzidine. The combined analysis of 68 cases and 107 controls from a cohort of production workers in China exposed to benzidine included 30 new cases and 67 controls not previously studied. NAT2 enzymatic activity phenotype was characterized by measuring urinary caffeine metabolite ratios. PCR‐based methods identified genotypes for NAT2, NAT1 and GSTM1. NAT2 phenotype and genotype data were consistent. A protective association was observed for the slow NAT2 genotype (bladder cancer OR = 0.3; 95% CI = 0.1 = 1.0) after adjustment for cumulative benzidine exposure and lifetime smoking. Individuals carrying NAT1wt/*10 and NAT1*10/*10 showed higher relative risks of bladder cancer (OR = 2.8, 95% CI = 0.8–10.1 and OR = 2.2, 95% CI = 0.6–8.3, respectively). No association was found between GSTM1 null and bladder cancer. A metaanalysis risk estimate of case‐control studies of NAT2 acetylation and bladder cancer in Asian populations without occupational arylamine exposures showed an increased risk for slow acetylators. The lower limit of the confidence interval (OR = 1.4; 95% CI = 1.0–2.0) approximated the upper confidence interval for the estimate obtained in our analysis. These results support the earlier finding of a protective association between slow acetylation and bladder cancer in benzidine‐exposed workers, in contrast to its established link as a risk factor for bladder cancer in people exposed to 2‐naphthylamine and 4‐aminobiphenyl. Study findings suggest the existence of key differences in the metabolism of mono‐ and diarylamines. Published 2005 Wiley‐Liss, Inc.

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Jianyu Rao

University of California

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Paul A. Schulte

National Institute for Occupational Safety and Health

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Yves Fradet

University of Oklahoma

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K.C. Balaji

University of Massachusetts Medical School

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Mark H. Kawachi

City of Hope National Medical Center

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Paul H. Lange

University of Washington

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