Biomedical subjects

Samir S Taneja

Publications and source records attributed to Samir S Taneja.

At least 37 records · Page 2Linked to original sources

PubMed2004

Neutral endopeptidase protein expression and prognosis in localized prostate cancer.

PURPOSE: Neutral endopeptidase (NEP) is a cell-surface peptidase that inactivates neuropeptide growth factors implicated in prostate cancer progression. The clinical significance of decreased NEP expression observed in prostate cancer is unclear. We investigated whether decreased NEP expression in localized prostate cancers is associated with prostate-specific antigen (PSA) relapse after radical prostatectomy. EXPERIMENTAL DESIGN: NEP expression patterns were examined by immunohistochemistry in 223 men, who underwent radical prostatectomy between 1990 and 2000 at the Veterans Administration Medical Center (New York, NY) with available representative tissues and adequate follow up. We also examined whether hypermethylation of the NEP promoter contributes to down-regulation of NEP protein expression in a subset of patients that showed decreased NEP expression (n = 22). RESULTS: Three patterns of NEP expression were observed: (a) membranous expression similar to benign prostate epithelium (n = 82; 37%); (b) complete loss of NEP expression in prostate cancer compared with adjacent benign prostate glands (n = 105; 47%); and (c) heterogeneous NEP expression (n = 36; 16%). In a multivariate analysis, complete loss of NEP expression was associated with PSA relapse after controlling for grade, stage, pretreatment PSA, and race simultaneously (hazard ratio, 1.99; 95% confidence interval, 1.13-3.52; two-sided chi(2) P = 0.017). In addition, DNA hypermethylation of the NEP promoter was frequently (73%) identified in a subset of 22 of cases that showed decreased NEP expression. CONCLUSION: Our data suggest that decreased NEP expression might contribute to progression of localized prostate cancer after surgery. Data also suggest that methylation is an important mechanism of NEP protein silencing. Larger prospective studies are required for confirmation.

DNA Methylation↗

PubMed2004

ART-27, an androgen receptor coactivator regulated in prostate development and cancer.

Androgen receptor trapped clone-27 (ART-27) is a newly described transcriptional coactivator that binds to the N terminus of the androgen receptor (AR). Given the vital importance of AR signaling in prostate growth and differentiation, we investigated the role of ART-27 in these processes. Immunohistochemical studies indicate that ART-27 protein is expressed in differentiated epithelial cells of adult human prostate and breast tissue. In prostate, ART-27 is abundant in AR-positive prostate luminal epithelial cells, in contrast to the stroma, where cells express AR but not ART-27. The use of a rat model of androgen depletion/reconstitution indicates that ART-27 expression is associated with the elaboration of differentiated prostate epithelial cells. Interestingly, regulated expression of ART-27 in the androgen-sensitive LNCaP prostate cancer cell line inhibits androgen-mediated cellular proliferation and enhances androgen-mediated transcription of the prostate-specific antigen (PSA) gene. Consistent with a growth suppressive function, we show that ART-27 expression levels are negligible in human prostate cancer. Importantly, examination of ART-27 protein expression in early fetal prostate development demonstrates that ART-27 is detected only when the developing prostate gland has proceeded from a solid mass of undifferentiated cells to a stage in which differentiated luminal epithelial cells are evident. Thus, ART-27 is an AR cofactor shown to be subject to both cell type and developmental regulation in humans. Overall, the results suggest that decreased levels of ART-27 protein in prostate cancer tissue may occur as a result of de-differentiation, and indicate that ART-27 is likely to regulate a subset of AR-responsive genes important to prostate growth suppression and differentiation.

Androgens↗

PubMed2004

Renal imaging: what the urologist wants to know.

Preoperative imaging in renal surgery is of utmost importance in contemporary surgical practice. From a diagnostic standpoint, imaging discovers many renal tumors incidentally before they become symptomatic. These tumors often are amenable to partial renal resection or minimally invasive surgical approaches. In general, surgical interventions for renal abnormalities have evolved to a less invasive endourologic or laparoscopic approach. Selection of the appropriate surgical intervention for renal tumors, collecting system tumors, and hydronephrosis depends heavily on the anatomy of the renal pathology. Thus, renal imaging is crucial in clinical decision-making. This article reviews the contribution of imaging to the surgical management of renal tumors, upper tract urothelial tumors, and ureteropelvic junction obstruction.

Decision Making↗

PubMed2004

Preoperative renal tumor evaluation by three-dimensional magnetic resonance imaging: Staging and detection of multifocality.

OBJECTIVES: To evaluate, retrospectively, the staging accuracy of three-dimensional magnetic resonance imaging (3D-MRI) in our institution as a prelude to a prospective comparison of 3D-MRI and 3D computed tomography (CT) for preoperative planning of partial nephrectomy. In recent years, the use of 3D-CT for preoperative evaluation and surgical planning in patients undergoing nephron-sparing surgery has gained considerable popularity. METHODS: The images of 26 consecutive patients evaluated by 3D-MRI as part of the preoperative imaging studies for renal tumor were evaluated retrospectively and compared with the surgical pathologic findings to evaluate the ability of 3D-MRI to predict tumor multifocality, tumor stage, collecting system invasion, and venous invasion. RESULTS: 3D-MRI accurately predicted tumor multifocality in 1 of 2 cases. Imaging identified five of seven multifocal lesions. Two subcentimeter lesions were missed. Preoperative staging was correct in 29 of 30 lesions (97% accuracy). One T3b tumor was incorrectly staged as T2. Venous invasion was identified in 2 of 3 cases (67% sensitivity), but no false-positive results were seen. 3D-MRI had 100% sensitivity and 88% specificity in the prediction of collecting system invasion. CONCLUSIONS: The staging accuracy of 3D-MRI appears to be quite good. Given the accuracy of this technique, along with the popularity of 3D imaging before renal surgery, these results provide the impetus for a future study directly comparing 3D-CT with 3D-MRI in the capacity of surgical preoperative planning.

Carcinoma, Papillary↗

PubMed2004

Imaging in the diagnosis and management of prostate cancer.

The current diagnosis and management of prostate cancer is largely based on the use of serum prostate-specific antigen (PSA) and pathologic risk factors such as Gleason score and clinical stage. The use of serum PSA in clinical practice has resulted in significant stage migration and, as such, imaging modalities historically utilized to stage prostate cancer are no longer able to reliably identify the small amounts of prostate cancer most often found at presentation. Molecular imaging techniques have focused on improving sensitivity and specificity for cancer detection through knowledge of specific attributes of disease biology. The evolution of imaging techniques has created a new role for imaging in the management of prostate cancer.

Journal Article↗

PubMed2004

ProstaScint(R) Scan: Contemporary Use in Clinical Practice.

Indium In 111 capromab pendetide (ProstaScint(R); Cytogen Corporation, Princeton, NJ), a radiolabeled monoclonal antibody to prostate-specific membrane antigen, offers a potential means of localizing sites of soft tissue metastasis in prostate cancer patients. Although the test was previously limited by poor positive predictive value and specificity owing to the inherent limitations of single photon emission computed tomography, improvements in techniques of anatomic localization, along with increased reader experience, have significantly improved its accuracy. In addition to the conventional roles for ProstaScint, such as staging and detection of relapse, a number of new potential applications have emerged.

Journal Article↗

PubMed2003

Volume indexes of total, free, and complexed prostate-specific antigen enhance prediction of extraprostatic disease extension in men with nonpalpable prostate cancer.

OBJECTIVES: To analyze the ability of volume-adjusted total, complexed, and free prostate-specific antigen (PSA) to predict organ-confined cancer at radical prostatectomy in patients with nonpalpable disease. METHODS: Collected sera were assayed for total PSA (tPSA), complexed PSA (cPSA), and free PSA (fPSA) in 78 men who underwent radical prostatectomy with nonpalpable prostate cancer. The pathologic results (organ-confined versus extraprostatic extension [EPE]), tPSA, cPSA, fPSA/tPSA ratio, cPSA/tPSA ratio, fPSA/cPSA ratio, tPSA density (tPSAD), cPSA density (cPSAD), and fPSA density (fPSAD) were compared by the Mann-Whitney U test and receiver operating characteristic curves. RESULTS: Fifteen men (19.2%) had pathologic EPE. After stratifying the patients on the basis of the Beckman tPSA, the cPSAD, tPSAD, and fPSAD were significant predictors of EPE when comparing their respective medians in individuals with tPSA greater than 4.0 ng/mL. Statistically significant differences were noted between patients with and without EPE for tPSAD (P = 0.0015), cPSAD (P = 0.0018), and fPSAD (P = 0.0022), but not for the fPSA/tPSA, cPSA/tPSA, and fPSA/cPSA ratios. The area under the receiver operating characteristic curve was similar for tPSA (0.539) and cPSA (0.542), as it was for tPSAD (0.708), cPSAD (0.700), and fPSAD (0.731). The specificity and diagnostic accuracy of tPSAD, cPSAD, and fPSAD were significantly greater than those of tPSA and cPSA (specificity P <0.001; diagnostic accuracy P <0.05). CONCLUSIONS: In men with nonpalpable prostate cancer, the density parameters of tPSA, cPSA, and fPSA performed equivalently and appeared to enhance the predictability of EPE.

Adenocarcinoma↗

PubMed2003

The role of partial nephrectomy for renal cell carcinoma in contemporary practice.

Partial nephrectomy has proved to be a safe and effective treatment modality, even for patients with normal contralateral kidneys. The indications for elective partial nephrectomy continue to evolve as contemporary series demonstrate low morbidity approaching that of radical nephrectomy. Furthermore, patients who undergo partial nephrectomy have a significantly decreased risk of future renal insufficiency. As such, a rationale exists for expanding indications in an era of excellent technical outcomes and increased patient longevity. Characterization of newer diagnostic (three-dimensional imaging) and treatment (laparoscopic partial nephrectomy, cryosurgery) modalities will allow continued evolution of nephron-sparing techniques.

Carcinoma, Renal Cell↗

PubMed2003

Complexed prostate specific antigen improves specificity for prostate cancer detection: results of a prospective multicenter clinical trial.

PURPOSE: Complexed (c) prostate specific antigen (PSA) has been shown to enhance specificity for prostate cancer (CaP) detection over total PSA (tPSA), although a large multi-institutional prospective evaluation was required to confirm these findings. We compared the clinical performance of cPSA with tPSA as a first line test for CaP detection and secondarily to determine if PSA ratios, namely percent free PSA (fPSA) and percent cPSA, can provide further enhancement in diagnostic performance over cPSA or tPSA. MATERIALS AND METHODS: Consecutive men scheduled for initial biopsy of the prostate were enrolled prospectively at each of 7 university centers and community based urology practices. Serum was collected and tested with the Immuno 1 (Bayer Diagnostics, Tarrytown, New York), tPSA and cPSA, and Access (Beckman, Inc., San Diego, California) fPSA and tPSA methods. RESULTS: A total of 831 patients were evaluated, of whom 313 (37.5%) were diagnosed with CaP. ROC curve analysis performed from the results of all samples and those within the clinically relevant cPSA ranges of 1.5 to 3.2, 1.5 to 5.1, 1.5 to 8.3 and 3.2 to 8.3 ng/ml (tPSA 2 to 4, 2 to 6, 2 to 10 and 4 to 10 ng/ml, respectively) indicated a significant improvement in the AUC ROC curve for cPSA compared with tPSA (p < or =0.001). Using cutoff points that provide a sensitivity of 80% to 95% for CaP detection within the 1.5 to 8.3 ng/ml cPSA range cPSA provided a statistically significant enhancement in specificity over tPSA of 6.2% to 7.9%. Within the cPSA range of 1.5 to 3.2 ng/ml using a cutoff point of 2.5 ng/ml for tPSA and 2.2 ng/ml for cPSA provided a specificity of 21.2% and 35%, respectively, and 85% sensitivity for CaP detection. PSA ratios provided no further enhancement in specificity over cPSA within these ranges. CONCLUSIONS: The use of cPSA as a single test provided improved specificity over tPSA. Percent fPSA and percent cPSA offered little to no additional benefit in the differentiation of benign and malignant disease at clinically relevant cPSA concentrations.

Aged↗

PubMed2003

Optimizing prostate biopsy strategies for the diagnosis of prostate cancer.

The importance of prostate biopsy in urologic practice has been magnified by the routine use of serum prostate-specific antigen in prostate cancer screening. Given the potential impact of the procedure on both patient care and health care costs, an optimal strategy for accurate and judicious detection of early prostate cancer is imperative. Maintaining maximal sensitivity and negative predictive value are equally important to the patient. In this article, we review recent modifications in prostate biopsy indications and techniques that may allow for a systematic biopsy approach to the patient in whom prostate cancer is suspected.

Journal Article↗

PubMed2003

A multidisciplinary approach to the management of hormone-refractory prostate cancer.

The patient with hormone-refractory prostate cancer (HRPC) presents unique management challenges for both the urologist and the medical oncologist. Because of a lack of effective treatment options, the management of patients with HRPC has historically been palliative. Over the past 10 years, the advent of relatively efficacious chemotherapeutic regimens, particularly taxane-based chemotherapy, has resulted in a desire to treat patients with HRPC more aggressively. The complex needs of these patients have made a multidisciplinary approach, inclusive of specialists with expertise in disease processes directly affecting the patient, the optimal means of treating HRPC. An understanding of the natural history and complications of HRPC, combined with a systemic evaluative process, can allow the multidisciplinary team to comprehensively address the needs of the individual patient with HRPC.

Journal Article↗

PubMed2003

A multidisciplinary approach to the management of hormone-refractory prostate cancer.

Journal Article↗

PubMed2002

Followup interval prostate biopsy 3 years after diagnosis of high grade prostatic intraepithelial neoplasia is associated with high likelihood of prostate cancer, independent of change in prostate specific antigen levels.

PURPOSE: Repeat biopsy has been advocated following the diagnosis of high grade prostatic intraepithelial neoplasia to exclude coexisting prostate cancer. We further define the natural history of high grade prostatic intraepithelial neoplasia by determining the incidence of prostate cancer 3 years following diagnosis. MATERIALS AND METHODS: A total of 31 men underwent followup interval biopsy 3 years after high grade prostatic intraepithelial neoplasia diagnosis in 1996 to 1997, regardless of change in serum prostate specific antigen (PSA) or digital rectal examination findings. A single pathologist reviewed all biopsy specimens. All men had a minimum of 12 biopsy cores taken at the time of diagnosis. RESULTS: A 3-year followup interval biopsy eight (25.8%) men had prostate cancer, 11 (35.5%) had high grade prostatic intraepithelial neoplasia only and 12 (38.7%) had no disease. Mean serum PSA at diagnosis and before the followup biopsy was 6.88 and 9.69 ng./dl., respectively (p = 0.008). Of the men 48% had less than a 1.0 unit increase in serum PSA. Upon univariate regression analysis change in serum PSA was not associated with the detection of prostate cancer (p >0.10). All 4 patients who subsequently underwent radical prostatectomy had organ confined disease. CONCLUSIONS: In a high proportion of men with high grade prostatic intraepithelial neoplasia prostate cancer will develop in a 3-year interval. Our findings support the concept that high grade prostatic intraepithelial neoplasia is a precursor to prostate cancer and that repeat biopsy at a delayed interval is recommended regardless of changes in PSA.

Adenocarcinoma↗

PubMed2002

Complexed prostate-specific antigen for early detection of prostate cancer in men with serum prostate-specific antigen levels of 2 to 4 nanograms per milliliter.

Complexed PSA (cPSA) has been shown to improve specificity in the detection of prostate cancer over that of total PSA (tPSA) testing in men with tPSA values greater than the cutoff value of 4.0 ng/mL. However, recent studies have reported a 25% incidence of prostate cancer in men with tPSA values in the 2.5- to 4.0-ng/mL range. We performed a multicenter study of cPSA in a population of men who underwent prostate biopsies because of elevated PSA levels or abnormal digital rectal examination (DRE). As part of this study, we sought to assess the clinical value of cPSA in comparison to tPSA, the free/tPSA ratio (f/tPSA) and the complexed/tPSA ratio (c/tPSA) in early detection of prostate cancer in men with tPSA values in the range of 2 to 4 ng/mL. The study was performed at 7 centers. Sera were drawn from men who underwent biopsy procedures consisting of >10 prostate tissue cores. Receiver operating characteristic (ROC) analysis was performed from the results of patients with tPSA values in the range of 2 to 4 ng/mL, including men with suspicious as well as unremarkable findings on DRE. Sera were collected and tested with the Bayer tPSA and cPSA assay and the Beckman free PSA and tPSA assays. ROC analysis was performed for all samples in the 2- to 4-ng/mL PSA range. At biopsy, 158 men had no evidence of malignancy and 57 (26.5%) were diagnosed with prostate cancer. ROC analysis indicated that the area under the curve (AUC) for cPSA was 0.64, which was statistically significantly greater than that achieved for tPSA (AUC, 0.57; P <0.0001). The AUC for f/tPSA and c/tPSA were 0.60 and 0.63, respectively, which was not statistically significantly different from that of tPSA or cPSA (P >or=0.252). A cutpoint of 2.5 ng/mL for tPSA and 2.1 ng/mL for cPSA provided a specificity of 20.3% and 34.2%, respectively, and sensitivity levels of 86%. Using cutpoints of 25% for f/tPSA and 74% for c/tPSA provided a specificity of 11.0% and 21.5%, respectively, and sensitivity levels of 97%. In all, >92% of the cancers treated with radical prostatectomy were organ confined, and the histologic grading of the tumors ranged from moderately to poorly differentiated with Gleason scores from 5 to 9. These data confirm that there is a high incidence of clinically significant prostate cancer in men with tPSA levels <4.0 ng/mL. Measurement of cPSA proved useful in stratifying men with tPSA values in the 2- to 4-ng/mL range into high- and low-risk groups for prostate cancer. The use of cPSA as a single test was found to enhance detection of prostate cancer over that of testing with tPSA and PSA ratios in men with tPSA values in the range of 2 to 4 ng/mL.

Adult↗

PubMed2002

Can volume measurement of the prostate enhance the performance of complexed prostate-specific antigen?

We assessed whether volume-based complexed prostate-specific antigen (cPSA) indices could enhance prostate cancer detection in men with serum total PSA (tPSA) between 2.5 and 10.0 ng/mL. Between December 1998 and April 2000, cPSA assay was measured in 480 men who underwent transrectal ultrasound-guided prostate biopsies at 7 institutions. We compared the usefulness of cPSA and its indices with the ratio of free PSA (fPSA) to tPSA (percent fPSA) for early detection of prostate cancer. Overall, 168 men (35%) had cancer. In the 341 men with tPSA between 4.01 and 10.0 ng/mL at approximately 90% sensitivity and areas under the receiver operating characteristics curve, the performances of volume-based parameters were significantly better (P <0.05) than those of tPSA and cPSA. In the 139 men with tPSA between 2.5 and 4.0 ng/mL, at 90% sensitivity, the specificity of the ratio of cPSA to tPSA (percent cPSA) was best, followed by cPSA density (cPSAD). In the 101 men with the history of a previous prostate biopsy, at approximately 90% sensitivity, the specificity of cPSAD was significantly better than those of tPSA and percent fPSA (P <0.05). In the 371 men with a total prostate volume of >or=30 cm(3) at approximately 90% sensitivity, the specificity of the cPSAD was significantly better than that of tPSA, percent fPSA, and cPSA (P <0.05). In the 109 men with a total prostate volume of <30 cm(3), at 90% sensitivity the specificity of cPSA and cPSAD was better than that of percent fPSA. In conclusion, volume-based cPSA can modestly enhance the performance of cPSA.

Humans↗

PubMed2002

Complexed prostate-specific antigen as a staging tool: results based on a multicenter prospective evaluation of complexed prostate-specific antigen in cancer diagnosis.

Within a 7-site prospective evaluation of the Bayer complexed prostate-specific antigen PSA (cPSA) assay, we analyzed the ability of cPSA to predict extracapsular extension (ECE) before radical prostatectomy. Included in this analysis were 152 men diagnosed with cancer, who subsequently underwent radical prostatectomy. Sera were tested with the Bayer total PSA (tPSA) and cPSA assays, and the Beckman free PSA (fPSA) and tPSA assays. Treating surgical pathology result as a binary variable (organ confined vs ECE), mean tPSA, cPSA, fPSA/tPSA (f/tPSA) ratios, tPSA density (tPSAD), and cPSA density (cPSAD) were compared by receiver operating characteristic (ROC) curves and univariate analysis. In all, 28 men (18.4%) had pathologically identified ECE. Between those with and without ECE, significant differences were observed for tPSA (P = 0.0127), cPSA (P = 0.0120), tPSAD (P = 0.0001), and cPSAD (P = 0.0002), but not f/tPSA (P = 0.3774) or c/tPSA (P = 0.2882). All tested parameters except f/tPSA (P = 0.376) and c/tPSA (P = 0.288) predicted ECE (P <0.05) by logistic regression. The ROC area under the curve (AUC) was identical for tPSA and cPSA (0.621) and for tPSAD (0.692) and cPSAD (0.691). Kendall-tau correlation coefficients also demonstrated the strongest correlation with ECE for cPSAD and tPSAD. Either alone or as a tPSAD calculation, cPSA carries equivalent staging ability to tPSA. The use of f/tPSA appears to be less effective in staging than either cPSA or tPSA, whereas the use of either cPSAD or tPSAD provides maximal staging accuracy. Therefore, cPSA could be applied as an accurate predictor of ECE independently or in a nomogram along with other predictive variables.

Aged↗

PubMed2002

Identification and characterization of ART-27, a novel coactivator for the androgen receptor N terminus.

The androgen receptor (AR) is a ligand-regulated transcription factor that stimulates cell growth and differentiation in androgen-responsive tissues. The AR N terminus contains two activation functions (AF-1a and AF-1b) that are necessary for maximal transcriptional enhancement by the receptor; however, the mechanisms and components regulating AR transcriptional activation are not fully understood. We sought to identify novel factors that interact with the AR N terminus from an androgen-stimulated human prostate cancer cell library using a yeast two-hybrid approach designed to identify proteins that interact with transcriptional activation domains. A 157-amino acid protein termed ART-27 was cloned and shown to interact predominantly with the AR(153-336), containing AF-1a and a part of AF-1b, localize to the nucleus and increase the transcriptional activity of AR when overexpressed in cultured mammalian cells. ART-27 also enhanced the transcriptional activation by AR(153-336) fused to the LexA DNA-binding domain but not other AR N-terminal subdomains, suggesting that ART-27 exerts its effect via an interaction with a defined region of the AR N terminus. ART-27 interacts with AR in nuclear extracts from LNCaP cells in a ligand-independent manner. Interestingly, velocity gradient sedimentation of HeLa nuclear extracts suggests that native ART-27 is part of a multiprotein complex. ART-27 is expressed in a variety of human tissues, including sites of androgen action such as prostate and skeletal muscle, and is conserved throughout evolution. Thus, ART-27 is a novel cofactor that interacts with the AR N terminus and plays a role in facilitating receptor-induced transcriptional activation.

Amino Acid Sequence↗

PubMedDate not supplied

The role of lymphadenectomy in the surgical management of renal cell carcinoma.

After decades of evaluation, the role of lymphadenectomy in the management of renal cell carcinoma remains a controversy. Contemporary series suggest that the true incidence of isolated lymph node metastases in clinically localized disease is small, and the location of such metastases is unpredictable. While several institutional series have suggested a therapeutic benefit for extended lymphadenectomy, there remains a lack of randomized data to support its routine use. Despite this, there remains a role for lymphadenectomy in individuals with high risk of lymph node metastasis or known lymphadenopathy in whom few other options exist for aggressive, potentially curative therapy.

Carcinoma, Renal Cell↗