Faculty Bibliography

Recognition of tumor cells by cytolytic T lymphocytes depends on cell surface MHC class I expression. As a mechanism to evade T cell recognition, many malignant cancer cells, including those of prostate cancer, down-regulate MHC class I. For the majority of human cancers, the molecular mechanism of MHC class I down regulation is unclear, although it is well established that MHC class I down-regulation is often associated with the down-regulation of multiple genes devoted to antigen presentation. Since the promyelocytic leukemia (PML) proto-oncogene controls multiple antigen-presentation genes in some murine cancer cells, we analyzed the expression of proto-oncogene PML and MHC class I in high-grade prostate cancer. We found that 30 of 37 (81%) prostate adenocarcinoma cases with a Gleason grade of 7-8 had more than 50% down-regulation of HLA class I expression. Among these, 22 cases (73.3%) had no detectable PML protein, while 4 cases (13.3%) showed partial PML down-regulation. In contrast, all 7 cases of prostate cancer with high expression of cell surface HLA class I had high levels of PML expression. Concordant down-regulation of HLA and PML was observed in different histological patterns of prostate adenocarcinoma. These results suggest that in high-grade prostate cancer, malfunction of proto-oncogene PML is a major factor in the down-regulation of cell surface HLA class I molecules, the target molecules essential for the direct recognition of cancer cells by cytolytic T lymphocytes

The androgen receptor (AR), a ligand-activated transcription factor of the steroid receptor superfamily, plays an important role in normal prostate growth and in prostate cancer. The recent identification of various AR co-factors prompted us to evaluate their possible roles in prostate tumorigenesis. To this end, we analyzed the expression of AR and eight of its co-factors by quantitative in situ RNA hybridization in 43 primary prostate cancers with different degrees of differentiation. Our results revealed nearly constant expression of AR and heterogeneous expression of AR co-factors, with increased expression of PIAS1 and Ran/ARA24, decreased expression of ELE1/ARA70, and no change in TMF1/ARA160, ARA54, SRC1, or TRAP220. Interestingly, whereas TMF1/ARA160, ELE1/ARA70, ARA54, RAN/ARA24, and PIAS1 were preferentially expressed in epithelial cells, another co-factor, ARA55, was preferentially expressed in stromal cells. Although the changes in levels of these co-activators did not correlate with Gleason score, their occurrence in high-grade prostatic intraepithelial neoplasia, suggests their involvement in initiation (or an early stage) of cancer. In addition, human prostate tumor cell proliferation and colony formation were markedly reduced by ELE1/ATRA70. Together, these findings indicate that changes in levels of expression of AR co-factors may play important, yet different, roles in prostate tumorigenesis

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

Prostate cancer is the most common male malignancy in western countries. Although primary prevention of prostate cancer is not possible, screening using prostate-specific antigen (PSA) may eliminate prostate cancers by definitive treatments. Prevention of clinically detectable prostate cancer requires earlier chemoprevention interventions. Because prostate cancer is histologically present in 30-50% of 30- to 50-year-old men, effective chemoprevention needs to inhibit not only prostate carcinogenesis but also growth and progression of these cancers. A prostate carcinogenesis animal model has been used to screen chemopreventive agents; inhibitory effects were found with 9-cis-retinoic acid, dehydroepiandrosterone, fluasterone, and the Bowman-Birk inhibitor and an isoflavone mixture which both occur in soy. Such results can be used to select agents for clinical trials. Besides large-scale long-duration prevention trials, trials of short/intermediate duration using smaller cohorts prior to or following radical prostatectomy may provide excellent and cost-effective approaches for chemopreventive agent efficacy testing. Intervention prior to surgery allows measurements of intervention agents and intermediate end-points in the prostate. These peri-surgical trials only assess inhibition of growth and progression of preexisting cancer, not real preventive effects, but they focus on clinically significant cancers. Such trials are an essential step in the development of antiprostate cancer chemoprevention agents

CONTEXT: Placental transmogrification of the lung is a term introduced to describe a peculiar histologic pattern characterized by formation of placental villuslike structures in the lung parenchyma. It has been reported to occur in association with bullous emphysema and lipomatosis. OBJECTIVES: To study the relationship between placental transmogrification and pulmonary hamartomas. DESIGN AND METHODS: Reports of 38 cases of pulmonary hamartomas during 18 years (1982-1999) were reviewed. All histologic slides of these cases were examined for the presence of villuslike papillary projections and placenta-like structures. Hamartomas with prominent papillary projections or placenta-like structures were further investigated to assess the histogenesis and proliferation of epithelial and stromal cells. Immunohistochemical analysis was performed on paraffin-embedded tissue using monoclonal antibodies against Ki-67 and thyroid transcription factor 1 (TTF-1) and polyclonal antibodies against c-Kit antigen (a stem cell factor receptor/mast cell growth factor receptor) in conjunction with Leder stain for naphthol-ASD-chloroacetate esterase. RESULTS: Placental transmogrification was identified in 6 of 38 cases of pulmonary fibrochondromatous hamartomas. The histologic change consisted of an abundant myxoid or edematous fibroadipose stroma with a respiratory epithelial lining, resulting in papillary projections that resembled immature placental villi. Epithelium lining the papillary projections was positive for TTF-1 (70%-90%) and Ki-67 (3%-5%). In contrast, stromal cells were negative for TTF-1 with only rare cells immunoreactive for Ki-67. A number of stromal spindle cells and occasional cells in epithelium were c-Kit immunoreactive; however, concurrent Leder stain demonstrated that these c-Kit-positive cells were mast cells and not stem cells. CONCLUSIONS: Placental transmogrification is frequently associated with pulmonary fibrochondromatous hamartomas and may be induced by or associated with a proliferation of lining epithelial components in the hamartomas. The significance of numerous mast cells within stroma of placental transmogrification is unclear and their possible role in inducing stromal proliferation needs to be further evaluated

The antiproliferative B-cell translocation gene 2 (BTG2(TIS21/PC3)) is emerging as an important regulator of cell cycle dynamics. BTG2(TIS21/PC3) expression increases in response to the induction of DNA damage, cell differentiation, cell quiescence, cell contact, and as part of a positive feedback mechanism in response to growth stimulation. The objective of the present study was to provide further insight into the biological function of BTG2(TIS21/PC3) by determining the expression levels and cellular localization of BTG2(TIS21/PC3) in a spectrum of normal human tissues and to determine the proliferative indices (based on Ki-67 staining) and apoptotic indices (based on TUNEL assay) in those cell populations where BTG2(TIS21/PC3) was differentially expressed. Highest levels of BTG2(TIS21/PC3) expression were seen in kidney proximal tubules, lung alveolar bronchial epithelium and in the basal cell layer of prostate acini. BTG2(TIS21/PC3) was expressed at significantly different levels within the different epithelial populations of the kidney (proximal vs distal tubules) and prostate (acinar basal cells vs lumenal cells). Moderate levels of expression were seen in the acinar cells of breast and pancreas and in the mucosal epithelium of the intestine. Low levels of expression were seen in neurons, hepatocyctes, the zona granulosa of the ovary, round spermatids and thyroid follicles. Our results therefore indicate an imperfect correlation between the terminally differentiated phenotype and BTG2(TIS21/PC3) expression, but no correlation between basal cellular proliferative or apoptotic indices and BTG2(TIS21/PC3) expression levels

Retrorectal cyst hamartoma (RCH) is a rare benign cystic lesion located in the retrorectal space. Malignancy arising in such lesions is very uncommon. In this study, 2 cases of mucinous adenocarcinoma arising in RCH are presented. In one case, dysplastic epithelium lined the cyst wall, surrounding the area of carcinoma and suggesting a dysplasia-carcinoma progression in RCH. Adenocarcinoma and the dysplastic epithelium were strongly positive for p53 and Ki-67 and showed negative staining for p21 by immunohistochemistry. These findings are suggestive of a mutation in the p53 gene in the adenocarcinoma and in dysplastic epithelium lining the cysts, similar to the dysplasia-carcinoma sequence described for the development of colonic adenocarcinoma

AIMS/OBJECTIVE:Lobular endocervical glandular hyperplasia of the uterine cervix is a rare pseudoneoplastic lesion of the uterine cervix, described recently. Our aim was to characterize the clinicopathological and immunohistochemical features of lobular endocervical glandular hyperplasia, to elucidate its pyloric gland phenotype, and to distinguish it from adenoma malignum of the uterine cervix. METHODS AND RESULTS/RESULTS:Nine cases of lobular endocervical glandular hyperplasia were studied histologically and immunohistochemically. The average age of the nine patients was 48.8 years (range 38-64 years). Six cases were found incidentally, whereas in three cases a watery vaginal discharge and imaging studies suggested adenoma malignum preoperatively. Microscopically, lobular endocervical glandular hyperplasia ranged from 1 mm to 20 mm (mean 6.8 mm) in the largest horizontal extent and 1 mm to 10 mm (mean 3.9 mm) in depth, and was characterized by lobular arrangements of small glands composed of low columnar cells with pale eosinophilic cytoplasm and bland nuclei. Three cases showed a pseudo-invasive growth. Intracytoplasmic mucin was predominantly PAS-positive, and seven cases showed immunoreactivity for M-GGMC-1, an antibody that reacts with pyloric gland-type mucin. Only focal and faint reactivity for CEA was seen, and ER was negative in all cases. The cytokeratin profile was CK7+/20- in all cases, in keeping with their Müllerian derivation. All three lesions examined contained chromogranin-positive endocrine cells. After surgery all patients are well without recurrent disease (mean follow-up was 48.4 months). CONCLUSIONS:Lobular endocervical glandular hyperplasia is a morphologically distinct pseudoneoplastic glandular lesion, which has unique phenotypic characteristics shared by pyloric glands of the stomach. Although most are found incidentally, some cases may show clinical and radiological features resembling those of adenoma malignum.

B cell translocation gene 2 (BTG2) is a p53 target that negatively regulates cell cycle progression in response to DNA damage and other stress. The objective of this study was to examine the expression, regulation and tumor suppressor properties of BTG2 in prostate cells. By immunohistochemistry BTG2 protein was detected in approximately 50% of basal cells in benign glands from the peripheral zone of the human prostate. BTG2 was expressed in all hyperproliferative atrophic peripheral zone lesions examined (simple atrophy, post-atrophic hyperplasia and proliferative inflammatory atrophy), but was undetectable or detectable at very low levels in the hyperproliferative epithelial cells of HGPIN and prostate cancer. BTG2 mRNA was detected in non-malignant prostate epithelial (PE) cells and in LNCaP cells, but not in PC-3 cells, consistent with p53-dependent regulation. In PE cells BTG2 protein was detected in areas of cell confluence by immunohistochemistry. BTG2 protein in LNCaP cells was undetectable by immunohistochemistry but was detected by immunoblotting at 8- to 9-fold lower levels than in PE cells. BTG2 protein levels were shown to be regulated by the ubiquitin-proteosome system. Forced expression of BTG2 in PC-3 cells was accompanied by a decreased rate of cell proliferation and decreased tumorigenicity of these cells in vivo. Taken together, these findings suggest that BTG2 functions as a tumor suppressor in prostate cells that is activated by cell quiescence, cell growth stimuli as part of a positive feedback mechanism and in response to DNA damage or other cell stress. The low steady-state levels of BTG2 protein in HGPIN and prostate cancer, a potential consequence of increased proteosomal degradation, may have important implications in the initiation and progression of malignant prostate lesions. Furthermore, these findings suggest that a significant component of the p53 G(1) arrest pathway might be inactivated in prostate cancer even in the absence of genetic mutations in p53