Seth K. Bechis

GATA-3 links tumor differentiation and dissemination in a luminal breast cancer model

How breast cancers are able to disseminate and metastasize is poorly understood. Using a hyperplasia transplant system, we show that tumor dissemination and metastasis occur in discrete steps during tumor progression. Bioinformatic analysis revealed that loss of the transcription factor GATA-3 marked progression from adenoma to early carcinoma and onset of tumor dissemination. Restoration of GATA-3 in late carcinomas induced tumor differentiation and suppressed tumor dissemination. Targeted deletion of GATA-3 in early tumors led to apoptosis of differentiated cells, indicating that its loss is not sufficient for malignant conversion. Rather, malignant progression occurred with an expanding GATA-3-negative tumor cell population. These data indicate that GATA-3 regulates tumor differentiation and suppresses tumor dissemination in breast cancer.

Impact of Age at Diagnosis on Prostate Cancer Treatment and Survival

PURPOSE Older men are more likely to be diagnosed with high-risk prostate cancer and to have lower overall survival. As a result, age often plays a role in treatment choice. However, the relationships among age, disease risk, and prostate cancer-specific survival have not been well established. PATIENTS AND METHODS We studied men in the Cancer of the Prostate Strategic Urologic Research Endeavor (CaPSURE) database with complete risk, treatment, and follow-up information. High-risk patients were identified by using the validated Cancer of the Prostate Risk Assessment (CAPRA) score. Competing risks regression was used to identify the independent impact of age on cancer-specific survival. We also analyzed the effect of local treatment on survival among older men with high-risk disease. RESULTS In all, 26% of men age ≥ 75 years presented with high-risk disease (CAPRA score 6 to 10). Treatment varied markedly with age across risk strata; older men were more likely to receive androgen deprivation monotherapy. Controlling for treatment modality alone, or for treatment and risk, age did not independently predict cancer-specific survival. Furthermore, controlling for age, comorbidity, and risk, older men with high-risk tumors receiving local therapy had a 46% reduction in mortality compared with those treated conservatively. CONCLUSION Older patients are more likely to have high-risk prostate cancer at diagnosis and less likely to receive local therapy. Indeed, underuse of potentially curative local therapy among older men with high-risk disease may in part explain observed differences in cancer-specific survival across age strata. These findings support making decisions regarding treatment on the basis of disease risk and life expectancy rather than on chronologic age.

Nucleotide-dependent domain movement in the ATPase domain of a human type IIA DNA topoisomerase.

Type IIA DNA topoisomerases play multiple essential roles in the management of higher-order DNA structure, including modulation of topological state, chromosome segregation, and chromatin condensation. These diverse physiologic functions are all accomplished through a common molecular mechanism, wherein the protein catalyzes transient cleavage of a DNA duplex (the G-segment) to yield a double-stranded gap through which another duplex (the T-segment) is passed. The overall process is orchestrated by the opening and closing of molecular “gates” in the topoisomerase structure, which is regulated by ATP binding, hydrolysis, and release of ADP and inorganic phosphate. Here we present two crystal structures of the ATPase domain of human DNA topoisomerase IIα in different nucleotide-bound states. Comparison of these structures revealed rigid-body movement of the structural modules within the ATPase domain, suggestive of the motions of a molecular gate.

GATA-3 and the regulation of the mammary luminal cell fate

The GATA family of transcription factors plays essential roles in the specification and maintenance of differentiated cell types. GATA-3 was identified in a microarray screen of the mouse mammary gland as the most highly expressed transcription factor in the mammary epithelium and is expressed exclusively in the luminal epithelial cell population. Targeted deletion of GATA-3 in mammary glands leads to profound defects in mammary development and inability to specify and maintain the luminal cell fate in the adult mouse. In breast cancer, GATA-3 has emerged as a strong predictor of tumor differentiation, estrogen-receptor status, and clinical outcome. GATA-3 maintains tumor differentiation and suppresses tumor dissemination in a mouse model of breast cancer. This review explores our current understanding of GATA-3 signaling in luminal cell differentiation, both in mammary development and breast cancer.

Diabetic Kidney Stone Formers Excrete More Oxalate and Have Lower Urine pH Than Nondiabetic Stone Formers

PURPOSE The epidemiological relationship between nephrolithiasis and type 2 diabetes mellitus is well-known. Patients with diabetes mellitus are at increased risk for nephrolithiasis and those with nephrolithiasis are at risk for diabetes mellitus. We examined 24-hour urine composition in stone formers with and without diabetes mellitus. MATERIALS AND METHODS We retrospectively reviewed a database of 462 stone forming patients to examine the relationship between hypertension and 24-hour urine composition. Multivariate linear regression models were adjusted for age, race, gender, body mass index, hypertension, relevant medications and 24-hour urine constituents. RESULTS On univariate analysis diabetic patients had significantly greater urine volume than nondiabetic patients (2.5 vs 2.1 l daily, p = 0.004). Those with diabetes mellitus also excreted less daily potassium (61.1 vs 68.8 mEq, p = 0.04), phosphate (0.84 vs 1.0 gm, p = 0.002) and creatinine (1405.5 vs 1562.8 mg, p = 0.03), and had significantly lower daily urine pH (5.78 vs 6.09, p <0.001) and CaP supersaturation (0.49 vs 1.20, p <0.001) than nondiabetic patients. On multivariate analysis compared to patients without diabetes mellitus those with type II diabetes mellitus had significantly lower urine pH (-0.34, 95% CI -0.48 to -0.21) and significantly greater urine oxalate (6.43 mg daily, 95% CI 1.26 to 11.60) and volume (0.38 l daily, 95% CI 0.13 to 0.64). CONCLUSIONS Results show that of stone formers patients with type II diabetes mellitus excrete significantly greater urinary oxalate and significantly lower urine pH than those without diabetes mellitus. These findings are important for treating nephrolithiasis since they may influence dietary counseling, medical management and stone prevention.

Personalized Medicine for the Management of Benign Prostatic Hyperplasia

PURPOSE Benign prostatic hyperplasia affects more than 50% of men by age 60 years, and is the cause of millions of dollars in health care expenditure for the treatment of lower urinary tract symptoms and urinary obstruction. Despite the widespread use of medical therapy, there is no universal therapy that treats all men with symptomatic benign prostatic hyperplasia. At least 30% of patients do not respond to medical management and a subset require surgery. Significant advances have been made in understanding the natural history and development of the prostate, such as elucidating the role of the enzyme 5α-reductase type 2, and advances in genomics and biomarker discovery offer the potential for a more targeted approach to therapy. We review the current understanding of benign prostatic hyperplasia progression as well as the key genes and signaling pathways implicated in the process such as 5α-reductase. We also explore the potential of biomarker screening and gene specific therapies as tools to risk stratify patients with benign prostatic hyperplasia and identify those with symptomatic or medically resistant forms. MATERIALS AND METHODS A PubMed® literature search of current and past peer reviewed literature on prostate development, lower urinary tract symptoms, benign prostatic hyperplasia pathogenesis, targeted therapy, biomarkers, epigenetics, 5α-reductase type 2 and personalized medicine was performed. An additional Google Scholar™ search was conducted to broaden the scope of the review. Relevant reviews and original research articles were examined, as were their cited references, and a synopsis of original data was generated with the goal of informing the practicing urologist of these advances and their implications. RESULTS Benign prostatic hyperplasia is associated with a state of hyperplasia of the stromal and epithelial compartments, with 5α-reductase type 2 and androgen signaling having key roles in the development and maintenance of the prostate. Chronic inflammation, multiple growth factor and hormonal signaling pathways, and medical comorbidities have complex roles in prostate tissue homeostasis as well as its evolution into the clinical state of benign prostatic hyperplasia. Resistance to medical therapy with finasteride may occur through silencing of the 5α-reductase type 2 gene by DNA methylation, leading to a state in which 30% of adult prostates do not express 5α-reductase type 2. Novel biomarkers such as single nucleotide polymorphisms may be used to risk stratify patients with symptomatic benign prostatic hyperplasia and identify those at risk for progression or failure of medical therapy. Several inhibitors of the androgen receptor and other signaling pathways have recently been identified which appear to attenuate benign prostatic hyperplasia progression and may offer alternative targets for medical therapy. CONCLUSIONS Progressive worsening of lower urinary tract symptoms and bladder outlet obstruction secondary to benign prostatic hyperplasia is the result of multiple pathways including androgen receptor signaling, proinflammatory cytokines and growth factor signals. New techniques in genomics, proteomics and epigenetics have led to the discovery of aberrant signaling pathways, novel biomarkers, DNA methylation signatures and potential gene specific targets. As personalized medicine continues to develop, the ability to risk stratify patients with symptomatic benign prostatic hyperplasia, identify those at higher risk for progression, and seek alternative therapies for those in whom conventional options are likely to fail will become the standard of targeted therapy.

Hypertension is Associated With Increased Urinary Calcium Excretion in Patients With Nephrolithiasis

PURPOSE The epidemiological relationship between nephrolithiasis and hypertension is well-known. Patients with hypertension are at increased risk for nephrolithiasis and those with nephrolithiasis are at risk for hypertension. Urine calcium or urine citrate may be related to hypertension status. We examined the relationship between hypertension and 24-hour urine composition in patients with nephrolithiasis. MATERIALS AND METHODS We retrospectively reviewed the database on 462 stone forming patients to examine the relationship between hypertension and 24-hour urine composition. Multivariate linear regression models were adjusted for age, race, gender, body mass index, diabetes mellitus and 24-hour urine constituents. Nominal logistic regression was also done to examine the hypertension prevalence by quintile of calcium and citrate excretion. RESULTS On adjusted multivariate analysis compared with normotensive stone formers those with hypertension excreted 25.6 mg per day more urine calcium, corresponding to a 12% increase in urinary calcium excretion. The relative risk of hypertension was significantly associated with quintile of calcium excretion but not with quintile of citrate excretion (1.29, 95% CI 1.02 to 1.61 vs 0.94, 95% CI 0.78 to 1.14). CONCLUSIONS In stone formers hypertension was associated only with significantly increased urine calcium. This association is important when treating patients with nephrolithiasis since those with hypertension may require unique dietary and medical therapy.

The Role of Race in Determining 24-Hour Urine Composition in White and Asian/Pacific Islander Stone Formers

PURPOSE We examined differences in 24-hour urine composition between white and Asian/Pacific Islander stone formers. MATERIALS AND METHODS We retrospectively reviewed the 24-hour urinalysis database at a metabolic stone clinic. We identified and included in the study patients 18 years old or older who presented for the initial metabolic stone evaluation when race was marked as white or Asian/Pacific Islander in the electronic medical record. Univariate analysis was done to compare 24-hour urine composition between white and Asian/Pacific Islander stone formers. We performed multivariate linear regression adjusted for possible confounders, including age, gender, body mass index, hypertension, diabetes mellitus, thiazide use, potassium citrate use and 24-hour urine chemistry (volume, pH, calcium, citrate, creatinine, oxalate, magnesium, phosphate, potassium, sodium, sulfate and uric acid). RESULTS Included in analysis were 371 white and 91 Asian/Pacific Islander patients. On univariate analysis Asian/Pacific Islander patients excreted significantly greater uric acid, and significantly less citrate, magnesium, phosphate and creatinine than white patients. On multivariate analysis Asian/Pacific Islander patients excreted significantly greater uric acid, and significantly less urine citrate, phosphate, creatinine and volume than white patients. CONCLUSIONS Significant differences exist in 24-hour urine chemistry between white and Asian/PI stone formers. Knowledge of these differences would be useful to evaluate and treat these patients, and prevent stone recurrence.

Age and Obesity Promote Methylation and Suppression of 5α-Reductase 2: Implications for Personalized Therapy of Benign Prostatic Hyperplasia

PURPOSE In men with symptomatic benign prostatic hyperplasia 5α-reductase inhibitors are a main modality of treatment. More than 30% of men do not respond to the therapeutic effects of 5α-reductase inhibitors. We have found that a third of adult prostate samples do not express 5α-reductase type 2 secondary to epigenetic modifications. We evaluated whether 5α-reductase type 2 expression in benign prostatic hyperplasia specimens from symptomatic men was linked to methylation of the 5α-reductase type 2 gene promoter. We also identified associations with age, obesity, cardiac risk factors and prostate specific antigen. MATERIALS AND METHODS Prostate samples from men undergoing transurethral prostate resection were used. We determined 5α-reductase type 2 protein expression and gene promoter methylation status by common assays. Clinical variables included age, body mass index, hypertension, hyperlipidemia, diabetes, prostate specific antigen and prostate volume. Univariate and multivariate statistical analyses were performed followed by stepwise logistic regression modeling. RESULTS Body mass index and age significantly correlated with methylation of the 5α-reductase type 2 gene promoter (p <0.05) whereas prostate volume, prostate specific antigen or benign prostatic hyperplasia medication did not correlate. Methylation highly correlated with 5α-reductase protein expression (p <0.0001). In a predictive model increasing age and body mass index significantly predicted methylation status and protein expression (p <0.01). CONCLUSIONS Increasing age and body mass index correlate with increased 5α-reductase type 2 gene promoter methylation and decreased protein expression in men with symptomatic benign prostatic hyperplasia. These results highlight the interplay among age, obesity and gene regulation. Our findings suggest an individualized epigenetic signature for symptomatic benign prostatic hyperplasia, which may be important to choose appropriate personalized treatment options.

Primary genitourinary melanoma: Epidemiology and disease-specific survival in a large population-based cohort

BACKGROUND Primary genitourinary (GU) melanoma is a rare disease, which is poorly characterized. OBJECTIVE To examine clinical characteristics and survival outcomes of primary GU melanoma among men and women. DESIGN, SETTING, AND PARTICIPANTS Retrospective study using the Surveillance, Epidemiology, and End Results database (1973-2010) was used to identify primary GU melanoma cases by tumor site and histology codes. We examined associations of GU melanoma with demographic, clinical, and pathologic characteristics, as well as disease-specific survival (DSS). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS DSS was calculated using the Kaplan-Meier method. Cox-proportional hazard models were used to calculate hazard ratios and 95% CI for factors associated with worse DSS. RESULTS AND LIMITATIONS A total of 1,586 histologically confirmed cases of primary GU melanoma were identified with a median age of 66.1 years (IQR: 55-80). Incidence of primary GU melanoma was 0.2cases/million among men and 1.80cases/million among women. Overall, 60.1% of patients had localized disease at presentation and 90.5% of patients had cancer-directed surgery. Patients with urothelial melanoma had the worst 5- and 10-year DSS (39% and 29%, respectively). Women with vulvar/vaginal melanoma had worse 5- and 10-year DSS compared to men with penile/scrotal melanoma. In multivariate analysis, decreased survival was associated with increasing age, distant stage, and lymph node involvement. Results are limited by the lack of standardized staging for primary GU melanoma and the retrospective design of our study. CONCLUSIONS Patients with primary GU melanoma present with advanced stage and have a poor prognosis. Women have worse DSS compared to men. DSS is negatively associated with advanced age at diagnosis, higher stage, and lymph node involvement. PATIENT SUMMARY Clinicians and patients must be aware of the poor disease-specific outcomes associated with primary GU melanoma. Most importantly, women fare worse than men and mucosal melanomas have worse outcomes compared to cutaneous melanomas.