Faculty Bibliography

Preneoplastic lesions for renal oncocytosis have not been well defined. We have attempted to identify the putative in-situ or dysplastic change in nephrectomy specimens with oncocytosis. Cases of multiple oncocytoma previously identified in radical nephrectomy specimens (n = 5) were reviewed for early lesions of renal oncocytosis by light microscopic analysis and by immunohistochemical studies for p53, bcl2 and MIB-1. Microscopic analysis showed that the renal cortical regions in all cases contain isolated groups of tubules partially or completely replaced by oncocytic cells with morphologic features resembling tumor cells in oncocytosis. The oncocytic cells within these tubules are increased in number and are arranged either as solid groups or as single layers in cystically dilated tubules, and may assume a hobnail appearance. They can be distinguished from small foci of oncocytosis as they do not form a coalescent group but are separated in part by intervening normal-appearing tubules. Cytologically, the cells have abundant eosinophilic, granular cytoplasm with a low nuclear/cytoplasmic ratio and demonstrate distinct cell borders. A very characteristic feature of these cells is the retraction space ('windows') between the oncocytic cells. Nuclear features of these cells are not distinctive from normal tubules. Immunostaining with Bcl-2, p53 and MIB-1 antibodies also does not differentiate the putative preneoplastic lesions from normal tubules. Thus, recognition of a putative dysplastic lesion for oncocytosis is possible by routine microscopic analysis. Identification of this lesion in a biopsy or partial nephrectomy specimen should raise the possibility of the existence of renal oncocytosis (multifocality), leading to adequate clinical management

Overexpression of HMGA2 is common in uterine leiomyomas (ULM). The expression of HMGA2 in its malignant counterpart - uterine leiomyosarcomas (ULMS) remains undetermined. Recently it has been shown that repression of HMGA2 by microRNA let-7s is a critical molecular regulatory mechanism associated with tumour growth in many tumours and cell types, including leiomyomas. To test whether HMGA2 and let-7s play a role in ULMS, we examined the levels of endogenous HMGA2 and let-7 expression and found a significant correlation between these two molecules in a case-matched cohort of human ULMS. We found that overexpression of HMGA2 and let-7-mediated HMGA2 repression is a relevant molecular alteration in ULMS. Disrupting the control of HMGA2 and let-7 pairs promotes ULMS cell growth in vitro

The following abstracts are compiled from Check Sample exercises published in 2008. These peer-reviewed case studies assist laboratory professionals with continuing medical education and are developed in the areas of clinical chemistry, cytopathology, forensic pathology, hematology, microbiology, surgical pathology, and transfusion medicine. Abstracts for all exercises published in the program will appear annually in AJCP

Histone deacetetylases (HDACs) are a group of corepressors of transcriptional activators and their levels of expression are potentially dysregulated in prostate cancer. Certain inhibitors of histone deacetylases show anti-tumor activity in prostate cancer cell lines. Here, we systemically studied the expression of HDACs in human prostate cancer and the suppression of prostate cancer growth and invasion by HDAC inhibitor SAHA. HDAC1-5 showed increased expression using a combination of DNA microarray, in-situ hybridization, and immunohistochemistry in benign and malignant human prostate tissue as well as RT-PCR and Western blot analysis on various PCa cell lines. Importantly, HDAC inhibitor SAHA suppressed, in particular, prostate cancer cell growth and invasion determined using cell proliferation and Matrigel invasion assays. The findings of this study show that the expression of HDACs and their associated corepressors are increased in prostate cancer in humans and HDAC inhibitor SAHA could serve as a potential therapeutic agent in prostate cancer in addition to anti-androgens

Androgen receptor (AR) is expressed in both stromal and epithelial cells of the prostate. The majority of studies on AR expression and function in prostate cancer is focused on malignant epithelial cells rather than stromal cells. In this study, we examined the levels of stromal AR in androgen-dependent and -independent prostate cancer and the function of stromal AR in prostate cancer growth and invasion. We showed that stromal AR levels were decreased in the areas surrounding cancerous tissue, especially in androgen-independent cancer. Using two telomerase-immortalized human stromal cell lines, one AR-positive and the other AR-negative, we demonstrated that stromal cells lacking AR stimulated cell proliferation of co-cultured prostate cancer cells in vitro and enhanced tumour growth in vivo when co-injected with PC3 epithelial cells in nude mice. In contrast, stromal cells expressing AR suppressed prostate cancer growth in vitro and in vivo. In parallel with cancer growth, in vitro invasion assays revealed that stromal cells lacking AR increased the invasion ability of PC3 cell by one order of magnitude, while stromal cells expressing AR reduced this effect. These results indicate a negative regulation of prostate cancer growth and invasion by stromal AR. This provides potentially new mechanistic insights into the failure of androgen ablation therapy, and the reactivation of stromal AR could be a novel therapeutic approach for treating hormone refractory prostate cancer.

ARA70 is a coactivator of androgen receptor (AR), a ligand-dependent transcription factor that plays an important role in prostate cancer. There are 2 variants of ARA70, the full length 70 kd ARA70alpha isoform and the internally spliced 35 kd ARA70beta isoform. Recent studies have suggested different expression and roles of the 2 isoforms in several endocrine malignancies, including prostate, breast, and ovarian cancers. To study the roles of these isoforms in cancers, we produced isoform-specific polyclonal antibodies. The anti-ARA70alpha antibody was raised in rabbits against 326 amino acid peptide corresponding to the internal deletion missing from ARA70beta (ARA70id), whereas the anti-ARA70beta antibody was raised against 18 amino acid polypeptide spanning the splice junction, with Gln-Gln motif unique to ARA70beta. The antisera were affinity purified on CNBr-activated sepharose 4B, and their specificity tested against bacterially expressed, Ni-column-purified ARA70alpha, ARA70beta, and ARA70id. The anti-ARA70alpha antibody recognized ARA70alpha and ARA70id, but not ARA70beta. The anti-ARA70beta antibody was specific to ARA70beta and did not cross-react with ARA70alpha or ARA70id. We then used these antibodies to detect ARA70 isoforms in crude extracts made of prostate cancer cell lines and performed immunohistochemical localization of these proteins in prostate tissues. ARA70beta localized to the cytosol, whereas ARA70alpha was found in the nucleus, supporting the notion of their dissimilar functions

OBJECTIVES: The role of socioeconomic factors in the worse outcome of black men with prostate cancer remains unclear. To determine whether socioeconomic factors affect prostate cancer outcomes, we studied a cohort of only black patients to minimize known confounding factors. METHODS: We studied black men treated with radical prostatectomy at New York Veterans Administration Medical Center and Memorial Sloan-Kettering Cancer Center between 1990 and 2005. A centralized pathology review process determined the Gleason score of all cases. Prostate-specific antigen (PSA) recurrence at both sites was defined as PSA of 0.2 or greater with a confirmatory rise. By matching patients' home zip codes to the U.S. Census Bureau database, we obtained corresponding socioeconomic data regarding median household income (income) and percentage of population with a high school (degree). We analyzed income, education, and clinical and pathological parameters for the whole cohort. RESULTS: We studied 430 black patients. They resided in neighborhoods where median household income was $41,498.10 and mean percentage of high school graduates was 73.4%. A total of 88 patients (20.9%) had PSA recurrence. Median follow-up for survivors was 37 months. Neither income nor education evaluated as continuous or categorical variables were predictors of PSA recurrence. When evaluated as composite categorical variable, the combination of greater income and education did not predict disease-free survival. CONCLUSIONS: Data suggest that socioeconomic factors have limited impact on PSA recurrence in black men treated with radical prostatectomy. Thus, biologic factors might have a role in the poor outcomes in this population

Androgen receptor (AR) mediates transcriptional activation of diverse target genes through interactions with various coactivators that may alter its function and help mediate the switch between prostate cell proliferation and differentiation. We recently identified p44/MEP50 as an AR coactivator and further showed that it is expressed primarily in the nucleus and cytoplasm of benign prostate epithelial and prostate cancer cells, respectively. We also showed that haploinsufficiency in p44(+/-) mice causes prostate epithelial cell proliferation. To establish direct cause-and-effect relationships, we have used p44 fusion proteins that are selectively expressed in the nucleus or cytoplasm of prostate cancer cells (LNCaP), along with RNAi analyses, to examine effects of p44 both in vitro and in vivo (in tumor xenografts). We show that preferential expression of p44 in the nucleus inhibits proliferation of LNCaP cells in an AR-dependent manner, whereas preferential expression of p44 in the cytoplasm enhances cell proliferation. These effects appear to be mediated, at least in part, through the regulation of distinct cell-cycle regulatory genes that include p21 (up-regulated by nuclear p44) and cyclin D2 and CDK6 (up-regulated by cytoplasmic p44). Importantly, we also demonstrate that altered p44 expression is associated with androgen-independent prostate cancer. Our results indicate that nuclear p44 and cytoplasmic p44 have distinct and opposing functions in the regulation of prostate cancer cell proliferation