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Mark A Rubin

Publications and source records attributed to Mark A Rubin.

107 records · Page 6Linked to original sources
PubMed2002

Preoperative parameters for predicting early prostate cancer recurrence after radical prostatectomy.

OBJECTIVES: To determine whether easily measurable prostate biopsy features could complement Gleason score, prostate-specific antigen (PSA), or clinical stage in predicting recurrence-free survival after prostatectomy. Information relating preoperative parameters to recurrence-free survival is needed to counsel patients with newly diagnosed prostate cancer regarding expectations for postprostatectomy cancer control. METHODS: The data of a cohort of 588 consecutive prostatectomy patients (median age 61 years, range 39 to 83) with ascertained preoperative data and up to 4 years of postprostatectomy follow-up were analyzed. Bivariate and multivariate Cox proportional hazards analysis evaluated preoperative factors (clinical stage, PSA, biopsy Gleason score, greatest percentage of a biopsy core involved by cancer [GPC], number of biopsy cores containing cancer, perineural invasion) to identify those relating significantly to recurrence-free survival. Functional forms of these factors were evaluated to optimize accuracy in predicting cancer control. RESULTS: The baseline parameters significantly affecting PSA-free survival included PSA level (P <0.01), biopsy Gleason score (P = 0.04), and GPC (P <0.01). Although clinical stage and perineural invasion had a marginal association with PSA-free survival as univariate factors, this association was not independently significant in multivariable analysis. The multivariate Cox model using PSA, Gleason score, and GPC was highly predictive of PSA free-survival (chi-square = 48.2, P = 0.0001). A set of plots representing these data can be used to identify the risk of early postoperative PSA recurrence on the basis of specific preoperative PSA, Gleason score, and GPC values. CONCLUSIONS: These findings provide a highly significant model and a simple tool for assisting preoperative patient counseling regarding predicted cancer control after radical prostatectomy.

Adult↗
PubMed2002

Prostate cancer involving the bladder neck: recurrence-free survival and implications for AJCC staging modification. American Joint Committee on Cancer.

OBJECTIVES: In the American Joint Committee on Cancer (AJCC) TNM staging system, prostate cancer involving the bladder neck after radical prostatectomy is considered pT4 disease, suggesting a high risk of recurrence. The recurrence risk with pathologic invasion of the bladder neck, however, has not been definitively compared with that associated with extra-organ disease. We therefore compared the recurrence risk in cases with bladder neck involvement with that of cases with extraprostatic extension and/or seminal vesicle invasion. METHODS: The study cohort was composed of 1123 men with clinically localized prostate cancer treated with prostatectomy as monotherapy. The preoperative prostate-specific antigen (PSA) level, bladder neck involvement, margin positivity, Gleason score, and other pathologic categories were assessed as covariates contributing to the PSA-recurrence risk in univariate and multivariable models. RESULTS: Bladder neck involvement was found in 60 (5%) of 1123 cases. In univariate analysis, the bladder neck was the site-specific margin with the greatest PSA-recurrence risk of focal involvement (relative risk 1.52, 95% confidence interval [CI] 1.15 to 2.00, P = 0.0030). The PSA-recurrence relative risk with extraprostatic extension was 3.05 (95% CI 2.13 to 4.38, P <0.0001) and with seminal vesicle invasion was 8.59 (95% CI 5.76 to 12.82, P <0.0001). In the multivariable model, the PSA-recurrence risk with bladder neck involvement (relative risk 1.19, 95% CI 0.72 to 1.96, P = 0.5) was not a significant independent prognostic factor. Extraprostatic extension (relative risk 2.25, 95% CI 1.54 to 3.27, P <0.0001) and seminal vesicle invasion (relative risk 4.12, 95% CI 2.57 to 6.62, P <0.0001) were significant independent predictors of PSA recurrence. CONCLUSIONS: Any staging system should be evidence based. The current AJCC system for staging bladder neck involvement, however, is contrary to the available evidence. Reclassification of bladder neck involvement as part of the pT3 category should be considered.

Analysis of Variance↗
PubMed2002

A functional thrombin receptor (PAR1) is expressed on bone-derived prostate cancer cell lines.

OBJECTIVES: To identify genes important in prostate cancer metastatic to bone. Bone-specific metastasis is a common feature of prostate cancer and a significant cause of morbidity. METHODS: To identify factors involved in organ-specific metastasis, we used cDNA microarray analysis to compare a bone-derived cell line, VCaP, with a soft tissue-derived cell line, DuCaP. Both cell lines were derived from the same patient and spontaneously passaged. RESULTS: Forty-five genes were differentially expressed, and only seven of these also had increased expression in VCaP compared with normal prostatic tissue. Of these, protease-activated receptor 1 (PAR1) was verified as having increased expression by reverse transcriptase-polymerase chain reaction and Northern blot analysis, as well as by immunohistochemistry. PAR1 expression in a panel of prostate cancer cell lines demonstrated increased expression in those cell lines derived from bone metastases. Alpha-thrombin stimulation of the VCaP cells produced a dose-dependent mobilization of intracellular calcium compared with DuCaP, suggesting that PAR1 expressed on the VCaP prostate cancer cell line is functional. CONCLUSIONS: These data indicate that a functional PAR1 is expressed on prostate cancer cell lines. The prostate cancer cell lines expressing PAR1 appear to have an association with increased bone metastases.

Bone Neoplasms↗
PubMed2002

Inadequate formalin fixation decreases reliability of p27 immunohistochemical staining: probing optimal fixation time using high-density tissue microarrays.

Immunohistochemical analysis of molecular targets in clinical tissues is increasingly becoming central to our ability to render diagnoses, to predict prognosis, to select patients for appropriate therapies, and to provide surrogate end points for therapeutic monitoring. For example, reduction of immunohistochemical staining for the cyclin-dependent kinase inhibitor p27(Kip1) has been proposed as a potential prognostic biomarker in prostate, breast, and gastrointestinal tumors. We observed that with our standard formalin fixation in rapidly processed (same-day) radical prostatectomy specimens, there is often a gradient of p27(Kip1) staining in normal prostate epithelium, with more staining near the periphery and less staining toward the center of the sample. This raised the hypothesis that the reliability of staining for p27(Kip1) is decreased in inadequately fixed tissues. The implications of this, if true, are that many studies using p27(Kip1) for prognostic purposes may be subject to unpredictable artifacts, and hence unreliable results, if the fixation of the specimens is not well controlled. The objectives of the present study were (1) to formally test the hypothesis that inadequate fixation time is responsible for apparent loss of p27(Kip1) nuclear staining and (2) to test a recently proposed method for improving the uniformity of immmunohistochemical staining using formalin injection. Prostate tissue sections from radical prostatectomy specimens were either processed immediately (zero time fixation) or fixed for 1, 2, 3, or 8 days in 10% neutral buffered formalin before processing into paraffin. To assure identical antigen retrieval and immunohistochemical staining conditions for specimens fixed for different lengths of time, 2 high-density tissue microarrays (TMAs), containing 564 tissue samples (0.6 mm in diameter) were constructed. Based on an estimate of the percentage of nuclei in normal prostatic epithelial secretory cells with strong staining, quality of p27(Kip1) staining was graded in a blinded fashion with respect to fixation time. There was a significant increase in the percentage of cores that were scored as "strong" as fixation time increased from 0 (same-day processing) to 1 or more days (P <.0001). Interestingly, even at 8 days of fixation, there was excellent staining that was superior to the same-day processing. Based on these results, we conclude the following: (1) for large clinical specimens that have been fixed briefly to decrease diagnostic turn-around time, the reliability of interpretation of immunohistochemical staining may be quite limited; (2) for p27(Kip1), decreased antigen staining as a result of the widely held concept of "overfixation" is much less of a problem than "underfixation"; (3) formalin injection produces a marked improvement in staining for several markers, including p27(Kip1); and (4) high-density TMAs, which assure identical test conditions, provide an excellent platform on which to evaluate the effects of tissue fixation on immunohistochemical staining.

Cell Cycle Proteins↗
PubMed2002

Spatial receptive field organization of macaque V4 neurons.

Subfield analysis of the receptive fields (RFs) of parafoveal V4 complex cells demonstrates directly that most RFs are tiled by overlapping second-order excitatory inputs that for any given V4 cell are predominantly selective to the same preferred values of spatial frequency and orientation. These results extend hierarchical principles of RF organization in the spatial, orientation and spatial frequency domains, first recognized in V1, to an intermediate extrastriate cortex. Spatial interaction studies across subfields demonstrate that the responses of V4 neurons to paired stimuli may either decrease or increase as a function of inter-stimulus distance across the width axis. These intra-RF suppressions and facilitations vary independently in magnitude and spatial extent from cell to cell. These results taken together with the relatively large RF sizes of V4 neurons - as compared with RF sizes of their afferent inputs - lead us to hypothesize a novel property, namely that classes of stimulus configurations that enhance areal summation while reducing suppressive interactions between excitatory inputs will evoke especially robust responses. We tested, and found support for, this hypothesis by presenting stimuli consisting of optimally tuned sine-wave gratings visible only within an annular region and found that such stimuli vigorously activate V4 neurons at firing rates far higher than those evoked by comparable stimuli to either the full-field or central core. On the basis of these results we propose a framework for a new class of neural network models for the spatial RF organizations of prototypic V4 neurons.

Animals↗
PubMed2002

Tissue microarray sampling strategy for prostate cancer biomarker analysis.

High-density tissue microarrays (TMA) are useful for profiling protein expression in a large number of samples but their use for clinical biomarker studies may be limited in heterogeneous tumors like prostate cancer. In this study, the optimization and validation of a tumor sampling strategy for a prostate cancer outcomes TMA is performed. Prostate cancer proliferation determined by Ki-67 immunohistochemistry was tested. Ten replicate measurements of proliferation using digital image analysis (CAS200, Bacus Labs, Lombard, IL, USA) were made on 10 regions of prostate cancer from a standard glass slide. Five matching tissue microarray sample cores (0.6 mm diameter) were sampled from each of the 10 regions in the parallel study. A bootstrap resampling analysis was used to statistically simulate all possible permutations of TMA sample number per region or sample. Statistical analysis compared TMA samples with Ki-67 expression in standard pathology immunohistochemistry slides. The optimal sampling for TMA cores was reached at 3 as fewer TMA samples significantly increased Ki-67 variability and a larger number did not significantly improve accuracy. To validate these results, a prostate cancer outcomes tissue microarray containing 10 replicate tumor samples from 88 cases was constructed. Similar to the initial study, 1 to 10 randomly selected cores were used to evaluate the Ki-67 expression for each case, computing the 90th percentile of the expression from all samples used in each model. Using this value, a Cox proportional hazards analysis was performed to determine predictors of time until prostate-specific antigen (PSA) recurrence after radical prostatectomy for clinically localized prostate cancer. Examination of multiple models demonstrated that 4 cores was optimal. Using a model with 4 cores, a Cox regression model demonstrated that Ki-67 expression, preoperative PSA, and surgical margin status predicted time to PSA recurrence with hazard ratios of 1.49 (95% confidence interval [CI] 1.01-2.20, p = 0.047), 2.36 (95% CI 1.15-4.85, p = 0.020), and 9.04 (95% CI 2.42-33.81, p = 0.001), respectively. Models with 3 cores to determine Ki-67 expression were also found to predict outcome. In summary, 3 cores were required to optimally represent Ki-67 expression with respect to the standard tumor slide. Three to 4 cores gave the optimal predictive value in a prostate cancer outcomes array. Sampling strategies with fewer than 3 cores may not accurately represent tumor protein expression. Conversely, more than 4 cores will not add significant information. This prostate cancer outcomes array should be useful in evaluating other putative prostate cancer biomarkers.

Biomarkers↗
PubMed2002

Alpha-Methylacyl-CoA racemase: a novel tumor marker over-expressed in several human cancers and their precursor lesions.

alpha-Methylacyl-CoA racemase (AMACR) is a mitochondrial and peroxisomal enzyme involved in the metabolism of branched-chain fatty acid and bile acid intermediates. Recently, AMACR has been demonstrated to be over-expressed in localized and metastatic prostate cancer, suggesting that it may be an important tumor marker. This study examines AMACR expression in a variety of human cancers and their precursor lesions. A survey of online Expressed Sequence Tags (ESTs) and Serial Analysis of Gene Expression (SAGE) databases revealed that AMACR was over-expressed in multiple cancers. The findings were confirmed by AMACR immunohistochemistry performed on several tissue microarrays containing common human tumors, including prostate, colon, and breast. Based on prior work, AMACR protein expression was divided into two categories: negative (negative to weak staining intensity) and positive (moderate to strong staining intensity). AMACR protein over-expression was found in a number of cancers, including colorectal, prostate, ovarian, breast, bladder, lung, and renal cell carcinomas, lymphoma, and melanoma. Greatest over-expression was seen in colorectal and prostate cancer with positive staining in 92% and 83% cases, respectively. AMACR over-expression was present in 44% of breast cancer cases. AMACR was also over-expressed in precursor lesions. Sixty-four percent of high-grade prostatic intraepithelial neoplasia and 75% colonic adenomas demonstrated positive AMACR protein expression. Reverse transcriptase-polymerase chain reaction for AMACR using laser capture microdissected prostate tissue confirmed gene over-expression at the mRNA level. In conclusion, our study suggests that AMACR is potentially an important tumor marker for several cancers and their precursor lesions, especially those linked to high-fat diets.

Adenoma↗
PubMed2002

Comparison of the basal cell-specific markers, 34betaE12 and p63, in the diagnosis of prostate cancer.

The basal cell-specific cytokeratin antibody (34betaE12) is widely used to aid in the diagnosis of cancer in challenging prostate needle biopsies (NBX) and transurethral resections of the prostate (TURP). Because prostate carcinoma (PCa) lacks basal cells, the absence of basal cell as determined by 34betaE12 can aid in the confirmation of a histologically suspicious lesion. However, false-negative staining occurs because of patchy cytoplasmic staining, making a definitive diagnosis difficult. A recently identified basal cell marker p63, a p53 homologue, stains basal cell nuclei but not secretory cells. The aim of this study is to determine if the p63 antibody offers any clinically useful advantage over 34betaE12 in the diagnosis of challenging atypical prostate lesions. Ninety-four cases, comprised of 25 consecutive prostate NBX and 2 TURP with an atypical suspicious focus, 55 NBX cases of histologically unequivocal PCa and 12 TURP specimen removed for benign prostate hyperplasia, were stained with the monoclonal antibodies 34betaE12 and 4A4 anti-p63. Basal cell staining intensity, percentage basal cell-positive glands in benign, malignant, and atypical foci, and number of benign glands not staining were evaluated for 34betaE12 and p63 stains. A total of 67 prostate NBX cases, including one TURP, were diagnosed with PCa, 1 atypical small acinar proliferation, 10 benign, and 4 cases excluded because of lost tissue on step sections. None of the 67 PCa NBX cases demonstrated 34betaE12 or p63 immunoreactivity (100% specific). Whereas 57 of 108 (53%) prostate NBX cores from 78 cases demonstrated a similar percentage of basal cell staining for both antibodies, 45 of 108 (41%) NBX cores demonstrated a higher percentage of p63 basal cell staining in benign glands. Only 6 of 108 NBX (6%) cores had a higher percentage of basal cell staining with 34betaE12 (Wilcoxon signed rank test, p <0.0001). Lack of basal cell staining in more than two benign glands occurred in 25 of 108 (23%) and 10 of 108 (9%) prostate NBX cores stained with 34betaE12 and p63, respectively. In the vast majority of atypical cases, both 34betaE12 and p63 staining differences were not clinically significant, except in 2 of 27 (7%) cases p63 offered diagnostic utility beyond the 34betaE12 immunostain. p63 in these cases demonstrated discontinuous but strong staining in atypical glands and adjacent benign glands, whereas 34betaE12 failed to stain optimally in this critical area. For 12 TURP cases the mean percentage basal cell positivity in benign glands was 75% and 95% for 34betaE12 and p63, respectively (p = 0.006). Lack of basal cell staining in more than two glands occurred in 12 of 12 (100%) and 2 of 12 (17%) TURP specimens stained with 34betaE12 and p63, respectively (p <0.0001). In summary, 34betaE12 and p63 are highly specific for basal cells and therefore are negative in areas of PCa. p63 is more sensitive than 34betaE12 in staining benign basal cells, particularly for TURP specimens, offering slight advantage over 34betaE12 in diagnostically challenging cases. p63 may be used as an alternative to 34betaE12 stain for difficult prostate lesions.

Adenocarcinoma↗
PubMed2002

Mediastinal seminoma in a patient with Wiskott-Aldrich syndrome.

Shortness of breath developed in an 18-year-old man with Wiskott-Aldrich syndrome, and he was found to have a large mediastinal mass. The gallium scan was positive, and biopsy indicated a seminoma. After treatment with four cycles of chemotherapy, the mass completely resolved. Despite severe thrombocytopenia, he required only two platelet transfusions during therapy. Although lymphomas make up the vast majority of mediastinal tumors in patients with Wiskott-Aldrich syndrome, a positive gallium scan should not preclude the diagnosis of seminoma or the need for confirmatory tissue diagnosis. This report shows the possibility of uneventful and successful treatment of malignancy in a patient with Wiskott-Aldrich syndrome and severe thrombocytopenia.

Adolescent↗
PubMed2002

Gene-expression profiles in hereditary breast cancer.

DNA microarray technology is revolutionizing the way fundamental biologic questions are addressed in the postgenomic era. In this study by Hedenfalk et al., the authors attempted to identify discrete gene expression profiles for patients with known hereditary breast cancers caused by mutations in BRCA1 and BRCA2, both of which increase the lifetime risk of developing breast cancer. The genome-wide perspective identified discrete sets of genes that discriminated between BRCA, BRCA2, and sporadic breast tumors. This commentary discusses some limitations of studying a small number of cases. The authors also address the need for validation on independent tumor sets, and the potential benefit of multivariable-type analyses to consider other potential confounding factors such as tumor grade, receptor status, tumor stage, and treatment information.

BRCA1 Protein↗
PubMed2002

Huntingtin-interacting protein 1 is overexpressed in prostate and colon cancer and is critical for cellular survival.

Huntingtin-interacting protein 1 (HIP1) is a cofactor in clathrin-mediated vesicle trafficking. It was first implicated in cancer biology as part of a chromosomal translocation in leukemia. Here we report that HIP1 is expressed in prostate and colon tumor cells, but not in corresponding benign epithelia. The relationship between HIP1 expression in primary prostate cancer and clinical outcomes was evaluated with tissue microarrays. HIP1 expression was significantly associated with prostate cancer progression and metastasis. Conversely, primary prostate cancers lacking HIP1 expression consistently showed no progression after radical prostatectomy. In addition, the expression of HIP1 was elevated in prostate tumors from the transgenic mouse model of prostate cancer (TRAMP). At the molecular level, expression of a dominant negative mutant of HIP1 led to caspase-9-dependent apoptosis, suggesting that HIP1 is a cellular survival factor. Thus, HIP1 may play a role in tumorigenesis by allowing the survival of precancerous or cancerous cells. HIP1 might accomplish this via regulation of clathrin-mediated trafficking, a fundamental cellular pathway that has not previously been associated with tumorigenesis. HIP1 represents a putative prognostic factor for prostate cancer and a potential therapy target in prostate as well as colon cancers.

Animals↗
PubMed2002

Differential expression of cytokeratins 8 and 20 distinguishes craniopharyngioma from rathke cleft cyst.

BACKGROUND: Craniopharyngiomas are epithelial neoplasms usually located in the sellar and suprasellar regions. Distinguishing craniopharyngioma from Rathke cleft cyst is sometimes difficult, and the distinction is clinically significant because Rathke cleft cysts have a better prognosis than craniopharyngiomas. DESIGN: We retrieved 10 cases with a primary diagnosis of craniopharyngioma and 5 cases with a diagnosis of Rathke cleft cyst for analysis. Five cases of normal pars intermedia of pituitary glands from autopsy served as controls. We evaluated the expression patterns of a broad range of low- to intermediate-molecular weight cytokeratins (CK7, CK8, CK10, CK17, CK18, CK19, and CK20) and high-molecular weight cytokeratins (K903: a combination of CK1, CK5, CK10, and CK14; and CK5/6) in these cases. RESULTS: Craniopharyngiomas had a cytokeratin expression pattern distinct from that of Rathke cleft cysts and pituitary gland pars intermedia: craniopharyngiomas did not express cytokeratins 8 and 20, whereas Rathke cleft cysts and pars intermedia of pituitary glands both expressed cytokeratins 8 and 20. CONCLUSION: The differential expression of cytokeratins distinguishes between craniopharyngioma and Rathke cleft cyst, and this difference could be useful for identifying craniopharyngioma in difficult cases in which only a small biopsy is available. The different cytokeratin profiles of craniopharyngioma and Rathke cleft cyst suggest that these lesions do not come from the same origin, or that they come from a different developmental stage of the pouch epithelium.

Adolescent↗
PubMed2002

Use of absorbable cyanoacrylate glue to repair an open cystotomy.

PURPOSE: A biodegradable cyanoacrylate glue was tested for its ability to close bladder injuries in an established porcine model. Inflammation and encrustation associated with this glue were examined in a rabbit model. MATERIALS AND METHODS: Four domestic pigs underwent transverse cystotomy, which was closed with absorbable cyanoacrylate glue. Four weeks later the bladder was distended with normal saline to evaluate the repair. A total of 45 rabbits underwent cystotomy, which was closed with polyglactin suture, absorbable cyanoacrylate glue or nonabsorbable 2-octyl cyanoacrylate glue. The bladder was harvested at 4 or 12 weeks to evaluate inflammation, microcalcification and encrustation. RESULTS: All 4 pig bladders tolerated a pressure of 200 mm. Hg 4 weeks after closure. In the rabbit bladders there was no difference in inflammation in the groups at 4 and 12 weeks. The absorbable glue and suture groups had less microcalcification than the 2-octyl cyanoacrylate glue group at 4 and 12 weeks (p = 0.01 and 0.02, respectively). Encrustation was less in the suture and absorbable glue groups than in the 2-octyl cyanoacrylate glue group at 4 and 12 weeks (p = 0.004 and 0.02, respectively). CONCLUSIONS: An experimental absorbable cyanoacrylate glue has the strength to seal a large cystotomy. The inflammatory response to absorbable glue is similar to that to suture at 12 weeks. Absorbable glue does not promote calcification. These properties may make it a suitable material for replacing or augmenting suture in the urinary tract.

Absorption↗
PubMedDate not supplied

Contemporary preoperative parameters predict cancer-free survival after radical prostatectomy: a tool to facilitate treatment decisions.

Prostate specific antigen (PSA) screening has heralded stage migration in prostate cancer toward cancers that may be readily eliminated by primary intervention. We sought to identify contemporary, preprostatectomy measures of cancer severity useful and significant for predicting postprostatectomy, recurrence-free survival. The association of baseline variables clinical variables (age, clinical stage, serum PSA, and race) and prostate biopsy parameters (Gleason score, presence of perineural invasion, number of biopsy cores with cancer, and the greatest percentage of a biopsy core occupied by cancer--GPC) with recurrence-free survival was evaluated by multivariate Cox proportional hazards regression among consecutive patients that underwent radical prostatectomy as primary therapy between 1994 and 2002. Tables were generated depicting expected 5-year recurrence-free survival after prostatectomy. From 1414 patients, 183 developed biochemical recurrence, 8 died from prostate cancer, and 31 died of all causes. Multivariable Cox regression found that clinical stage, PSA, Gleason score, and the greatest percentage of a biopsy core involved by cancer (GPC), were each significant determinants of post-prostatectomy, PSA recurrence-free survival (P < 0.05 for each). Gleason score and GPC were also significantly associated with clinical recurrence-free survival and cancer death, whereas other biopsy parameters and PSA were not. The amount of cancer in a biopsy core is a significant predictor of recurrence-free survival after prostatectomy, and is a simple clinical measure that complements baseline PSA, and Gleason score in predicting outcome. Tabulated 5-year PSA-free survival outcomes, stratified by these preoperative parameters, provide a basis for preoperative counseling of patients regarding postprostatectomy cancer control expectations.

Adenocarcinoma↗
PubMedDate not supplied

Postprostatectomy cancer-free survival of African Americans is similar to non-African Americans after adjustment for baseline cancer severity.

African American men with localized prostate cancer are less likely than White men to receive a radical prostatectomy. This disparity may exist because African American men have prostate cancers that are more biologically aggressive. We investigated if similar stage cancers of African American men and White men show differences in cancer control after radical prostatectomy. Men with localized prostate cancer who underwent radical prostatectomy during a 6-yr period were stratified by race, and time to prostate-specific antigen recurrence was measured. We used Chi-square and t-tests to compare baseline clinical and pathological factors based on race. Cox proportional hazards model was used to determine effects of race on cancer control while controlling for baseline measures of cancer severity. There were 1,228 cases evaluated. At baseline, African American men were treated at a significantly younger age than White men (P = 0.0027) but showed no significant difference in prostate-specific antigen PSA, Gleason score, pathology stage, maximum tumor dimension, and surgical margin status. Multivariable Cox proportional hazards analysis controlling for cancer severity at prostatectomy revealed that cancer-free survival was not worse among African Americans compared to other subjects (P = 0.16). The responsiveness of prostate cancers among African American men to radical prostatectomy was similar to White men of similar stage and grade. Early detection in African American men may facilitate diagnosis of cancer amenable to prostatectomy. Studies are needed to evaluate the possible interaction of prostate cancer stage and grade shift in African American men and the disease free survival in this population.

Black or African American↗
PubMedDate not supplied

Expression of the platelet-derived growth factor receptor in prostate cancer and treatment implications with tyrosine kinase inhibitors.

The platelet-derived growth factor receptor (PDGFR) is a receptor tyrosine kinase overexpressed in a subset of solid tumors and therefore is the target of drugs inhibiting this function such as imatinib mesylate (Gleevec). Thus far, drug therapy has played a limited role in the treatment of localized prostate cancer (PCa). This study characterizes PDGFR-beta expression in a wide spectrum of PCa samples to provide empirical data as part of a rational treatment strategy. A survey of five published prostate expression array studies, including 100 clinically localized PCa, did not identify tumors with increased PDGFR-beta expression level. Protein expression of PDGFR-beta, as determined by immunohistochemistry, revealed 5% of clinically localized PCa and 16% of metastatic PCa cases to show moderate or strong expression. To develop a strategy to detect patients most likely to profit from Gleevec treatment, we analyzed cDNA expression array data from 10,000 transcripts for PDGFR-beta expression and divided tumors in groups based on PDGFR-beta expression level. Performing a supervised analysis to identify potential comarkers of PDGFR-beta in PCa, we identified a set of genes whose expression was associated with PDGFR-beta status including early growth response 1 (Egr1), an upstream effector of PDGF (4.2-fold upregulation), alpha-methylacyl-CoA racemase, as well as v-Maf and neuroblastoma suppressor of tumorigenicity (both with a 2.2-fold downregulation). Taken together, this study suggests that only a small subset of PCas may be amenable to tyrosine kinase inhibitors specific for PDGFR.

Antineoplastic Agents↗