Pre-neoplastic lesions of the prostate

Androgen Metabolism Gene Polymorphisms, Associations with Prostate Cancer Risk and Pathological Characteristics: A Comparative Analysis between South African and Senegalese Men

Prostate cancer is the most common cancer in men in developed countries and the leading cause of mortality in males in less developed countries. African ethnicity is one of the major risk factors for developing prostate cancer. Pathways involved in androgen metabolism have been implicated in the etiology of the disease. Analyses of clinical data and CYP3A4, CYP3A5, and SRD5A2 genotypes were performed in South African White (120 cases; 134 controls), Mixed Ancestry (207 cases; 167 controls), and Black (25 cases; 20 controls) men, as well as in Senegalese men (86 cases; 300 controls). Senegalese men were diagnosed earlier with prostate cancer and had higher median PSA levels compared to South African men. Metastasis occurred more frequently in Senegalese men. Gene polymorphism frequencies differed significantly between South African and Senegalese men. The CYP3A4 rs2740574 polymorphism was associated with prostate cancer risk and tumor aggressiveness in South African men, after correction for population stratification, and the SRD5A2 rs523349 CG genotype was inversely associated with high-stage disease in Senegalese men. These data suggest that variants previously associated with prostate cancer in other populations may also affect prostate cancer risk in African men.

Screening for Prostate Cancer by Digital Rectal Examination and PSA Determination in Senegal

Objectives. The goal of our study was to investigate the prevalence of prostate cancer in an unselected population of Senegalese men. Patients and Methods. We conducted the study over two years (2008 and 2009) on an unselected population of 572 Senegalese men, aged 35 and older. The following parameters have been investigated: the subject's age, the presence or absence of urination disorders, the family's history of prostate cancer or prostate surgery, the aspects of the prostate on digital rectal examination (DRE), the total PSA level, and the outcomes of the prostate biopsies. Data entry was performed with Epi Info 6 software and was analyzed and recorded using Excel software. We performed mean and frequency calculations. Results. The mean age of our patients was 65.5 years, with extremes of 38 and 93 years. Age groups from 50 to 59 and from 60 to 69 were the most represented. DRE was normal in the age group from 35 to 39, and only one patient in the age group from 40 to 49 had a prostate nodule. PSA level was greater than or equal to 4 ng/mL in 66 cases. A total of 5.4% patients had a PSA level greater than or equal to 10 ng/mL. Only two patients in the age group from 40 to 49 had a PSA level greater than 4 ng/mL. Of the 72 biopsies we performed, prostatic adenocarcinoma was found in 30.6% of the cases. It is the only type of prostate cancer we found in our series. The cases of prostate cancer were mostly observed in the age groups from 60 to 69 and from 70 to 79. No cases were detected for ages younger than 50. DRE gave indications of possible adenocarcinoma in 27.30% cases. Its sensitivity was 27%, while its positive predictive value was estimated at 35%. Of all positive biopsies, 4.5% had a PSA level between 0 and 3.9 ng/mL. In this case, the sensitivity of PSA was 95.5%, and the positive predictive value was 31.8%. High-grade intraepithelial neoplasiae were observed in 21 cases. Conclusion. Prostate cancer is frequent in Senegal, and screening remains the best way for early diagnosis.

Immunohistochemical study of cell proliferation, Bcl-2, p53, and caspase-3 expression on preneoplastic changes induced by cadmium and zinc chloride in the ventral rat prostate

This work was directed to evaluate immunoexpression of markers for apoptosis, resistance to apoptosis, and cell proliferation, as well as estimates of nuclear size in ventral prostate of rats treated with cadmium chloride and cadmium+zinc chloride because a possible protective effect of zinc has been postulated. The following variables were studied: volume fraction (VF) of Bcl-2 immunostaining, percentage of cells immunoreactive to proliferating cell nuclear antigen (LIPCNA) and p53 (LIp53), numerical density of caspase-3 immunoreactive cells (NV caspase-3), and estimates of volume-weighted mean nuclear volume (upsilonV). The LIPCNA and VF of Bcl-2 were significantly increased in the treated animals. The dysplasias (independent of their origin) showed a significant increase of the LIp53, NV caspase-3, and upsilonV in comparison with normal acini from treated and control animals. It can be concluded that cell proliferation is enhanced in long-term cadmium-exposed rats, and exposure to zinc combined with cadmium had no effect on any of the variables studied when comparing with normal acini. The increase of nuclear upsilonV could indicate a more aggressive behavior for pretumoral lesions.

An investigation into the spatial relationship between prostate intraepithelial neoplasia and cancer

The distribution of high grade prostate intraepithelial neoplasia (PIN) and cancer was analysed in 18 separate areas from 89 radical prostatectomy specimens that had been sectioned and digitally imaged. When the occurrence of each type of pathology was summated a predilection was demonstrated for both pathologies in the apex of the prostate and a linear relationship was found between the frequency of cancer and high grade PIN (r(2)=0.744, P<0.05). This relationship was strongest at the apex (r(2)=0.621, P<0.005), lower in the midgland (r(2)=0.828, P<0.05) and bordered on significance at the base (r(2)=0.621, P<0.063). These results support the theory that cancer could obliterate high grade PIN as it over grows the areas once occupied by PIN.Prostate Cancer and Prostatic Diseases (2001) 4, 97-100

Morphological identification of the patterns of prostatic intraepithelial neoplasia and their importance

High grade prostatic intraepithelial neoplasia (PIN) is the most likely precursor of prostatic carcinoma. PIN has a high predictive value as a marker for carcinoma, and its identification in biopsy specimens warrants repeat biopsy for concurrent or subsequent carcinoma. The only methods of detection are biopsy and transurethral resection; PIN does not greatly raise the concentration of serum prostate specific antigen (PSA) or its derivatives, does not induce a palpable mass, and cannot be detected by ultrasound. Androgen deprivation decreases the prevalence and extent of PIN, suggesting that this form of treatment might play a role in chemoprevention. Radiotherapy is also associated with a decreased incidence of PIN.

Pre- and postnatal testosterone administration induces proliferative epithelial lesions with neuroendocrine differentiation in the dorsal lobe of the rat prostate

BACKGROUND

Androgens are implicated in the pathogenesis of prostatic carcinoma. We have elucidated the role of pre- and postnatal testosterone administration in the occurrence of proliferative lesions as well as neuroendocrine (NE) cells in the rat prostatic complex.

METHODS

Female rats were given a single dose of 9 mg testosterone enantate i.m. on day 15 of pregnancy; it gave a high testosterone exposure to the fetus in the early organogenetic period of the rat prostatic complex. One group of the male offspring was followed without further testosterone treatment; a second group received testosterone only in the pubertal period; a third group was given testosterone from puberty and throughout life (46 weeks). These groups were compared to parallel groups (1A-1C) of male offspring without a testosterone supplement in pregnancy.

RESULTS

The serum testosterone concentrations in the rats receiving testosterone were significantly higher than those of control rats. Histopathologically, the testosterone-induced proliferative lesions, mainly hyperplastic, were almost exclusively located in the dorsal lobe. Chromogranin A-immunoreactive (CgA-IR) cells were rarely found normally, but occurred more often in the proliferative lesions (P < 0.001).

CONCLUSIONS

The incidence of proliferative lesions in rats exposed to testosterone only in puberty was comparable to the incidence found in those rats receiving testosterone in puberty and throughout life. This finding may have clinical implications for young athletes, who use testosterone as an anabolic drug. The occurrence of CgA-IR cells increased in proliferative lesions in the dorsal lobe of the rat prostatic complex.

Distinct altered patterns of p27KIP1 gene expression in benign prostatic hyperplasia and prostatic carcinoma

BACKGROUND

The p27KIP1 gene, whose protein product is a negative regulator of the cell cycle, is a potential tumor suppressor gene; however, no tumor-specific mutations of this gene have been found in humans. This study was undertaken to identify and to assess potential alterations of p27KIP1 gene expression in patients with benign prostatic hyperplasia (BPH) and patients with prostate cancer.

METHODS

We analyzed 130 prostate carcinomas from primary and metastatic sites, as well as prostate samples from normal subjects and from patients with BPH. Immunohistochemistry and in situ hybridization were used to determine the levels of expression and the microanatomical localization of p27 protein and messenger RNA (mRNA), respectively. Immunoblotting and immunodepletion assays were performed on a subset of the prostate tumors. Associations between alterations in p27KIP1 expression and clinicopathologic variables were evaluated with a nonparametric test. The Kaplan-Meier method and the logrank test were used to compare disease-relapse-free survival. Prostate tissues of p27Kip1 null (i.e., knock-out) and wild-type mice were also evaluated.

RESULTS

Normal human prostate tissue exhibited abundant amounts of p27 protein and high levels of p27KIP1 mRNA in both epithelial cells and stromal cells. However, p27 protein and p27KIP1 mRNA were almost undetectable in epithelial cells and stromal cells of BPH lesions. Furthermore, p27Kip1 null mice developed enlarged (hyperplastic) prostate glands. In contrast to BPH, prostate carcinomas were found to contain abundant p27KIP1 mRNA but either high or low to undetectable levels of p27 protein. Primary prostate carcinomas expressing lower levels of p27 protein appeared to be biologically more aggressive (two-sided P = .019 [Cox regression analysis]).

CONCLUSIONS/IMPLICATIONS

On the basis of these results, we infer that loss of p27Kip1 expression in the human prostate may be causally linked to BPH and that BPH is not a precursor to prostate cancer.

Altered expression of RET proto-oncogene product in prostatic intraepithelial neoplasia and prostate cancer

BACKGROUND

The RET proto-oncogene encodes a protein that belongs to the tyrosine kinase growth factor receptor family. Germline point mutations in RET are found in individuals with multiple endocrine neoplasia (MEN) syndromes, and gene rearrangements have been reported in papillary thyroid cancers. We recently identified transcripts of the RET proto-oncogene in human prostate cancer xenografts and prostate cancer cell lines by means of reverse transcription-polymerase chain reaction analyses. The purpose of this study was to investigate Ret protein expression in human prostate tissue.

METHODS

Ret protein expression was evaluated immunohistochemically in formalin-fixed, paraffin-embedded whole-prostate sections. The prostate specimens were obtained from 30 patients with prostate cancer after radical prostatectomies. Ret protein expression was compared in tumor foci and benign prostatic tissue. Medullary thyroid carcinoma tissue associated with an MEN syndrome and papillary thyroid cancer tissue served as positive controls.

RESULTS

Ret appeared to be overexpressed in high-grade (histopathologically advanced) prostatic intraepithelial neoplasia (PIN) and prostate cancer when compared with its expression level in benign prostatic secretory epithelium. In addition, there was an apparent increase in Ret protein expression with decreased cellular differentiation, i.e., increasing Gleason pattern.

CONCLUSION

Expression of the RET proto-oncogene in benign prostatic epithelium, high-grade PIN, and histopathologically advanced prostate cancer suggests that RET may play a role in the growth of both benign and neoplastic prostate epithelial cells.