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S S Taneja

Publications and source records attributed to S S Taneja.

12 recordsLinked to original sources
PubMed2003

Genetic counseling for prostate cancer risk.

Major risk factors for developing prostate cancer, including positive family history and African-American ethnicity, can be quantified for genetic counseling. Factors increasing familial risk for prostate cancer are closer degree of kinship, number of affected relatives, and early age of onset (< 50 years) among the affected relatives. Genetic testing may be useful for modification of risk, but currently should be performed only within the context of a well-designed research study that will determine penetrance and genotype-phenotype correlation of specific mutations. Even in the absence of genetic testing, African-American men and men with a strong family history of prostate cancer may opt to initiate screening by prostate specific antigen (PSA) and digital rectal exam (DRE) screening at age 40.

Adult↗
PubMed2001

Androgen stimulated cellular proliferation in the human prostate cancer cell line LNCaP is associated with reduced retinoblastoma protein expression.

To elucidate the mechanism of androgen-dependent cellular proliferation in prostate cancer, androgen-dependent alterations of individual cell cycle regulatory proteins in the androgen-sensitive prostate cancer cell line LNCaP were evaluated. LNCaP cells were deprived of androgens by culture in steroid-depleted media for 5 days, which resulted in the maximal accumulation of cells in G(0)/G(1) phase of the cell cycle. The mitogenic concentration of the synthetic androgen R1881 was established as 0.1 nM using cell proliferation assay. Protein and mRNA levels of particular cyclins, cyclin-dependent kinases (Cdks), cyclin-dependent kinase inhibitors (Ckis), and the retinoblastoma proteins (Rb) were assessed. Androgen stimulation resulted in a post-transcriptional reduction in Rb protein levels, an increase in Rb phosphorylation at serine 780 and an accumulation of high molecular weight Rb protein species. Androgen stimulation also induced the expression of the Cdk2 and Cdk1 as well as their regulatory partners, cyclin A and cyclin B, resulting in a corresponding increase in cyclin A/Cdk2 activity in vitro. Pulse-chase showed decreased Rb protein stability in androgen-treated LNCaP cells. Collectively, our findings suggest a novel mechanism of androgen-dependent prostate cancer growth in which androgen stimulation results in decreased Rb protein expression in LNCaP cells. The observation of decreased Rb protein stability in the setting of increased phosphorylation supports the concept of phosphorylation mediated protein degradation. We propose that the observed reduction in Rb protein level occurs through Rb degradation via the ubiquitin/proteasome pathway, and is preceded by selective Rb phosphorylation by cyclin A/Cdk2 and cyclin B/Cdk1.

Androgens↗
PubMed2001

Volume-specific cutoffs are necessary for reproducible application of prostate-specific antigen density of the transition zone in prostate cancer detection.

OBJECTIVES: To determine the effect of prostate volume on the specificity of prostate-specific antigen density (PSAD) and PSAD of the transition zone (PSA-TZ) in the detection of prostate cancer. METHODS: Between February 1994 and April 1998, transrectal ultrasound-guided prostate needle biopsies were performed in 235 men with serum prostate-specific antigen (PSA) levels between 4.0 and 10.0 ng/mL. The PSAD and PSA-TZ specificities were calculated at 95% sensitivity cutoff levels generated from the whole group, as well as from cohorts stratified by transition zone index or prostate volume. RESULTS: Statistical significance was noted between the benign (n = 176) and prostate cancer (n = 59) groups for all tested PSA parameters. At 95% sensitivity, PSA-TZ carried a specificity of 37.5% compared with 29.6% for PSAD. When applying a single 95% sensitivity cutoff derived from the entire group to individual volume-stratified cohorts, the specificity decreased to 0% in glands less than 30 g in size. A 95% sensitivity PSA-TZ cutoff generated individually for volume-stratified cohorts of glands less than 30, 30 to 40, and 40 to 60 g resulted in more consistent specificity of 28.2%, 35.2%, and 45.7% for each cohort, respectively. CONCLUSIONS: Unlike whole group-derived cutoffs, the use of volume-specific PSA-TZ cutoffs allows consistently high specificity in all volume-stratified cohorts. The discrepancies in the PSA-TZ and PSAD specificities in published reports are likely due to the application of published cutoffs to populations of differing prostate volumes. The use of volume-specific cutoffs results in reproducible specificity in populations with differing prostate volume distribution, and thereby definitively resolves the differences in PSA-TZ specificity reported in published reports.

Biomarkers, Tumor↗
PubMed2001

Is repeat prostate biopsy for high-grade prostatic intraepithelial neoplasia necessary after routine 12-core sampling?

OBJECTIVES: To determine whether repeat biopsy is necessary when the diagnosis of high-grade prostatic intraepithelial neoplasia (HGPIN) is made with a 12-core biopsy. Repeated biopsy has been recommended for individuals with HGPIN noted on sextant prostate biopsy because of the high likelihood of cancer detection. Recently, we have recommended the routine use of 12 cores, rather than 6, to improve cancer detection. METHODS: The charts of all patients undergoing prostate biopsy during a 2-year period at the Manhattan Veterans Administration Medical Center were reviewed. Patients diagnosed with HGPIN on a 12-core biopsy were identified, and those undergoing a repeat 12-core biopsy within 1 year of the initial biopsy were evaluated to determine the rate of cancer detection. RESULTS: A total of 619 men underwent biopsy during the study period. Of 103 men diagnosed with HGPIN, 43 underwent a repeat biopsy within 1 year at the discretion of the managing urologist. The mean age and median prostate-specific antigen level of those undergoing a repeat biopsy was 65.5 years and 5.37 ng/mL, respectively. At the time of the repeat biopsy, 1 patient was found to have cancer (2.3%), 20 had HGPIN (46.5%), 20 had benign pathologic findings (46.5%), and 1 patient (2.3%) had atypical small acinar proliferation. CONCLUSIONS: A repeat biopsy after the diagnosis of HGPIN on 12-core prostate biopsy rarely results in cancer detection. In the absence of other factors increasing the suspicion of cancer, immediate repeat biopsy for HGPIN diagnosed on a 12-core biopsy is unnecessary.

Aged↗
PubMed1999

Does site specific labeling of sextant biopsy cores predict the site of extracapsular extension in radical prostatectomy surgical specimen.

PURPOSE: We determine whether site specific labeling of sextant prostate biopsy cores predicts the site of extracapsular extension in a radical prostatectomy specimen, thereby justifying increased cost of pathological evaluation. MATERIALS AND METHODS: Between January 1994 and December 1997, 407 radical prostatectomies were performed at our institution by a single surgeon (H. L.). Surgical specimens showing extracapsular extension were examined by a single pathologist (J. M.) to identify the site of extension. Several different methods of submitting transrectal ultrasound guided biopsy cores were used since the majority of cases did not undergo biopsy at our institution. In 243 cases sextant biopsies were labeled right versus left. Of these cases 103 specimen cores were individually labeled. The ability of the positive biopsy core location to predict the location of extracapsular extension in the surgical specimen was determined. Univariate and multivariate logistic regression analyses were performed to assess the ability of biopsy core characteristics, including Gleason score, percentage of cancer in the core, core location and number of positive cores in the specimen, to predict the site of extracapsular extension. A similar analysis was performed for the 243 cases with right versus left core labeling. RESULTS: The positive predictive value was 8.9+/-2.2% for a single positive core to identify the location of extracapsular extension correctly in the individually labeled core cases. The absence of cancer in a sextant biopsy had a negative predictive value of 96.9+/-1.4%. The overall sensitivity was 59.4+/-3.8% for a positive biopsy core. In the right versus left core cases the positive predictive value was 12.9+/-3.0% with a sensitivity of 85.1+/-3.2%. In an individual core Gleason score 8 or greater and/or cancer in more than 50% of tissue enhanced the positive predictive value but not to a clinically useful level. Multivariate logistic regression identified Gleason score, number of positive ipsilateral cores and base position of the positive biopsy as the most predictive variables for the site of extracapsular extension. CONCLUSIONS: When submitting biopsy specimens by individually labeled core or right versus left core, the positive predictive value of an individual positive core for the location of extracapsular extension is not sufficient to guide the surgical decision to spare or excise a neurovascular bundle. Therefore, the clinical information provided by individually labeled or right versus left core labeling does not justify the increased associated costs.

Biopsy↗
PubMed1998

Prospects for gene therapy in human prostate cancer.

Prostate cancer is the most common neoplasm in men and a significant cause of mortality in affected patients. Despite significant advances, current methods of treatment are effective only in the absence of metastatic disease. Gene therapy offers a renewed hope of using the differential characteristics of normal and malignant tissue in constructing treatment strategies. Several clinical trials in prostate cancer gene therapy are currently under way, using immunomodulatory genes, anti-oncogenes, tumor suppressor genes and suicide genes. A continued understanding of the etiological mechanisms involved in the establishment and progression of prostate cancer, along with advances in gene therapy technology, should make gene therapy for prostate cancer therapeutically valuable in the future.

Cancer Vaccines↗
PubMed1995

Gene therapy: principles and potential.

Gene therapy is a new and provocative means of treating human malignancy. Insight into the mechanisms of growth and growth regulation within cancer cells has offered multiple potential methods for genetic intervention. The application of gene therapy to prostate cancer is in its infancy. The development of both adenoviral and retroviral replication deficient vectors has provided the ability consistently to transfer genes into cancer cells. Although the ideal gene for transfer has not yet been clearly identified, many genes capable of altering the biological behaviour of prostate cancer exist. Selection of the appropriate gene is highly dependent on the desired therapeutic outcome. A gene therapy strategy, whether dependent on ex vivo or in vivo transfection, must ultimately be tailored to meet the specific needs of the disease to be treated. The potential to treat locally confined disease, preventing subsequent metastasis, or widespread metastatic disease exists. The ultimate success of a prostate cancer gene therapy strategy will rely on comprehensive investigation of the biology of the tumour and careful planning of an effective intervention.

Cytokines↗
PubMed1994

Management of disseminated kidney cancer.

The approach to disseminate renal cell carcinoma (RCC) has evolved significantly in recent years, largely owing to the progress of biologic therapy development. With increasing knowledge of biologic therapy come several dilemmas, including the choice of cytokine therapy, the appropriate mode of delivery, the selection of candidates for given therapeutic options, and the role of cytoreductive nephrectomy in immunotherapy protocols. This article reviews the historical development of immunotherapy and the lessons learned from previous experience and offers a logical approach to the patient with disseminated RCC.

Carcinoma, Renal Cell↗