DNA quantitation of intraepithelial neoplasia and invasive carcinoma of the prostate

Preneoplasia in the prostate gland with emphasis on high grade prostatic intraepithelial neoplasia

There are a variety of morphological patterns and processes that have been implicated in the pathogenesis of prostate cancer. Prostatic intraepithelial neoplasia (PIN), inflammation with or without atrophy, and adenosis (atypical adenomatous hyperplasia) have all been given candidate status as precursor lesions of prostatic adenocarcinoma. Based on decades of research, high grade prostatic intraepithelial neoplasia (HPIN), a proliferative lesion of prostatic secretory cells, has emerged as the most likely morphological pre-invasive lesion involved in the evolution of many but not all prostatic adenocarcinomas. In this manuscript, we briefly discuss other proposed precursors of prostatic adenocarcinoma and then focus on the history, diagnostic criteria and morphology of HPIN. The incidence of HPIN and its relationship to prostate cancer is reviewed. The differential diagnosis of large glandular patterns in the prostate is discussed in depth. Finally, we summarise the recent clinicopathological studies evaluating the clinical significance of HPIN and discuss follow-up strategies in men diagnosed with HPIN.

Genomic approaches to outcome prediction in prostate cancer

Prostate cancer remains a common cause of cancer death in men. Applications of emerging genomic technologies to high-quality prostate cancer models and patient samples in multiple contexts have made significant contributions to our molecular understanding of the development and progression of prostate cancer. Genomic analysis of DNA, RNA, and protein alterations allows for the global assessment of this disease and provides the molecular framework to improve risk classification, outcome prediction, and development of targeted therapies. In this review, the author focused on highlighting recent work in genomics and its role in evaluating molecular modifiers of prostate cancer risk and behavior and the development of predictive models that anticipate the risk of developing prostate cancer, prostate cancer progression, and the response of prostate cancer to therapy. This framework has the exciting potential to be predictive and to provide personalized and individual treatment to the large number of men diagnosed with prostate cancer each year. Cancer 2009;115(13 suppl):3046-57. (c) 2009 American Cancer Society.

A novel gene signature for molecular diagnosis of human prostate cancer by RT-qPCR

BACKGROUND

Prostate cancer (CaP) is one of the most relevant causes of cancer death in Western Countries. Although detection of CaP at early curable stage is highly desirable, actual screening methods present limitations and new molecular approaches are needed. Gene expression analysis increases our knowledge about the biology of CaP and may render novel molecular tools, but the identification of accurate biomarkers for reliable molecular diagnosis is a real challenge. We describe here the diagnostic power of a novel 8-genes signature: ornithine decarboxylase (ODC), ornithine decarboxylase antizyme (OAZ), adenosylmethionine decarboxylase (AdoMetDC), spermidine/spermine N(1)-acetyltransferase (SSAT), histone H3 (H3), growth arrest specific gene (GAS1), glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and Clusterin (CLU) in tumour detection/classification of human CaP.

METHODOLOGY/PRINCIPAL FINDINGS

The 8-gene signature was detected by retrotranscription real-time quantitative PCR (RT-qPCR) in frozen prostate surgical specimens obtained from 41 patients diagnosed with CaP and recommended to undergo radical prostatectomy (RP). No therapy was given to patients at any time before RP. The bio-bank used for the study consisted of 66 specimens: 44 were benign-CaP paired from the same patient. Thirty-five were classified as benign and 31 as CaP after final pathological examination. Only molecular data were used for classification of specimens. The Nearest Neighbour (NN) classifier was used in order to discriminate CaP from benign tissue. Validation of final results was obtained with 10-fold cross-validation procedure. CaP versus benign specimens were discriminated with (80+/-5)% accuracy, (81+/-6)% sensitivity and (78+/-7)% specificity. The method also correctly classified 71% of patients with Gleason score<7 versus > or =7, an important predictor of final outcome.

CONCLUSIONS/SIGNIFICANCE

The method showed high sensitivity in a collection of specimens in which a significant portion of the total (13/31, equal to 42%) was considered CaP on the basis of having less than 15% of cancer cells. This result supports the notion of the "cancer field effect", in which transformed cells extend beyond morphologically evident tumour. The molecular diagnosis method here described is objective and less subjected to human error. Although further confirmations are needed, this method poses the potential to enhance conventional diagnosis.

The 3-dimensional structure of isolated and small foci of prostatic adenocarcinoma: the morphologic relationship between prostatic adenocarcinoma and prostatic intraepithelial neoplasia

BACKGROUND

Transitional histopathologic changes from high-grade prostatic intraepithelial neoplasia (HGPIN) into early prostatic adenocarcinoma (PAC) have not been well studied to date. To investigate the histogenesis of PAC, we examined isolated and small foci of PAC (ISPAC) found in prostatectomy specimens and the 3-dimensional structure of these foci.

DESIGN

Twelve consecutive radical prostatectomy specimens having ISPAC, performed for peripheral zone PAC (10 cases) and for transitional zone PAC (2 cases), of Gleason score were studied. One to 2 tissue blocks with representative sections were used.

RESULTS

Eight ISPAC, with Gleason score 3 + 3 had complete serial sections of the entire lesion. PAC consisted of continuous, tortuous and branching tubules and acini arising from benign ducts displaying: (a) HGPIN in 5 ISPAC and (b) no HGPIN in 3 ISAPC. At the junctions between benign epithelia with or without HGPIN and malignant epithelia, there were transitional lesions with HGPIN involving small ducts and acini.

CONCLUSIONS

PAC develops as a result of multiple outpouchings of the epithelium with formation of small ducts and acini showing cytologic atypia and gradual or abrupt loss of basal cells. Grade 3 ISPAC consists of a system of continuous duct pushing into the stroma. There is also evidence suggestive of HGPIN as being both a precursor lesion and an accompanying lesion of PAC.

Molecular aspects of diagnostic nucleolar and nuclear envelope changes in prostate cancer

Prostate cancer is still diagnosed by pathologists based on subjective assessment of altered cell and tissue structure. The cellular-level structural changes diagnostic of some forms of cancer are known to be induced by cancer genes, but the relation between specific cellular-level structural features and cancer genes has not been explored in the prostate. Two important cell structural changes in prostate cancer-nucleolar enlargement and nuclear envelope (NE) irregularity-are discussed from the perspective that they should also relate to the function of the genes active in prostate cancer. Enlargement of the nucleolus is the key diagnostic feature of high-grade prostatic intraepithelial neoplasia (PIN), an early stage that appears to be the precursor to the majority of invasive prostate cancers. Nucleolar enlargement classically is associated with increased ribosome production, and production of new ribosomes appears essential for cell-cycle progression. Several cancer genes implicated in PIN are known (in other cell types) to augment ribosome production, including c-Myc, p27, retinoblastoma, p53, and growth factors that impact on ERK signaling. However, critical review of the available information suggests that increased ribosome production per se may be insufficient to explain nucleolar enlargement in PIN, and other newer functions of nucleoli may therefore need to be invoked. NE irregularity develops later in the clonal evolution of some prostate cancers, and it has adverse prognostic significance. Nuclear irregularity has recently been shown to develop dynamically during interphase following oncogene expression, without a requirement for post-mitotic NE reassembly. NE irregularity characteristic of some aggressive prostate cancers could reflect cytoskeletal forces exerted on the NE during active cell locomotion. NE irregularity could also promote chromosomal instability because it leads to chromosomal asymmetry in metaphase. Finally, NE irregularity could impact replication competence, transcriptional programming and nuclear pore function.

High-grade prostatic intraepithelial neoplasia

High-grade prostatic intraepithelial neoplasia (PIN) is now accepted as the most likely preinvasive stage of adenocarcinoma, almost two decades after its first formal description. PIN has a high predictive value as a marker for adenocarcinoma, and its identification warrants repeat biopsy for concurrent or subsequent invasive carcinoma. The only method of detection is biopsy; PIN does not significantly elevate serum prostate-specific antigen (PSA) concentration or its derivatives and cannot be detected by current imaging techniques, including ultrasound. Most patients with PIN will develop carcinoma within 10 years. PIN is associated with progressive abnormalities of phenotype and genotype, which are similar to cancer rather than normal prostatic epithelium, indicating impairment of cell differentiation with advancing stages of prostatic carcinogenesis. Androgen deprivation therapy decreases the prevalence and extent of PIN, suggesting that this form of treatment may play a role in chemoprevention.

Identification of isolated and early prostatic adenocarcinoma in radical prostatectomy specimens with correlation to biopsy cores: clinical and pathogenetic significance

Prostatic adenocarcinoma (PAC) is a multifocal disease. In this study, we identified isolated and small foci of PAC (ISPAC) in radical prostatectomy specimens, described the histopathologic features, investigated their zonal distribution in the prostate and their relationship with large tumor nodules, and correlated the findings with those of preceding biopsy cores. One hundred and thirty radical prostatectomy specimens performed for PAC or for urothelial carcinoma of the urinary bladder with incidental PAC were reviewed for identification of ISPAC. Prostates were serially sectioned in the horizontal plane and submitted in toto for microscopic examination. ISPAC were defined as foci of PAC measuring less than 3 mm in maximum diameter. There were 461 ISPAC identified in 114 cases. They were distributed in the transitional zone (TZ) (18 foci), the apex (73 foci), the anterior horn of the non-TZ (NTZ) (118 foci), the base (8 foci), and the remaining NTZ (244 foci). ISPAC usually consisted of groups of small acini with a GS ranging from 2 to 7 (3 + 4). GSs of ISPAC consisted of single grade or two consecutive grades equal to or lower than those of the main PAC. ISPAC were more often located in close proximity to large tumor nodules. The number of ISPAC increased with the tumor volume up to 3 cm3, then decreased as the PAC became more extensive (p value = 0.02, statistically significant). Prostates with NTZ PAC <1.5 cm3 and TZ PAC or prostates containing 4 or more than 4 ISPAC tended to be frequently associated with small foci of PAC in biopsy cores In this study, we identified ISPAC that likely represent foci of PAC in early development and account for the multicentricity and heterogeneity of PAC. ISPAC in the NTZ were common and may account for small foci of PAC or atypia in biopsy cores. Although these small foci of PAC or atypia in biopsy cores without accompanying higher GS PAC were often associated with significant PAC, they may also occasionally represent insignificant or vanishing PAC in subsequent radical prostatectomies.

KAI1/CD82 protein expression in primary prostate cancer and in BPH associated with cancer

Current prognostic methods in primary prostate cancer cannot accurately identify patients with clinically significant disease at highest risk of developing metastases. This study examined KAI1/CD82 metastasis suppressor expression by quantitative immunohistochemical analysis of benign prostatic hyperplasia (BPH) and prostate cancer specimens. Altogether, prostate cancers exhibited significant KAI1 overexpression compared to BPH not associated with cancer (P = 0.022). Increased KAI1 expression in well and moderately differentiated cancers, above levels seen in BPH, with decreased expression in poorly differentiated cancers was observed. Interestingly, KAI1 expression in BPH associated with cancers was significantly higher than in BPH not associated with cancer (P = 0.009). Thus, KAI1 overexpression may restrain onset and early stage prostate cancer development, whilst its loss may predispose the patient to more aggressive cancer behaviour. Altered KAI1 expression in prostate cancers and BPH associated with cancer may have important diagnostic roles.

Risk of concurrent prostate cancer in cystoprostatectomy specimens is related to volume of high-grade prostatic intraepithelial neoplasia

OBJECTIVES

To assess the relationship of prostatic intraepithelial neoplasia (PIN) with both incidental and clinical carcinoma of the prostate.

METHODS

We retrospectively reviewed prostate histology in 48 men (group 1) who underwent surgical removal of the prostate for diagnoses other than prostate cancer, as well as in 64 men (group 2) who underwent radical prostatectomies. Both groups were assessed for the presence and extent of high-grade (HG-) PIN and compared with respect to patient age, Gleason score, and volume of prostate cancer.

RESULTS

HG-PIN was present in 40 of 48 (83%) group 1 cases. Forty-six percent of these cases (22 of 48) had incidental prostate cancer. Twenty-nine of 48 (60%) group 1 patients with HG-PIN had multifocal or extensive disease. Twenty of 22 (91%) incidental prostate cancers were present in 29 prostates with multifocal or extensive HG-PIN. In contrast, only 2 of 19 (11%) cases with absent to focal HG-PIN had prostate cancer. The association of multifocal or extensive HG-PIN with incidental prostate cancer was significant (P = 0.001); the relationships of extent of HG-PIN and cancer volume (P = 0.06) or high Gleason score (P = 0.017) were not significant. HG-PIN was present in 61 of 64 (95%) group 2 cases. The associations of extent of HG-PIN and cancer volume (P = 0.169) or high Gleason score (P = 0.156) were not significant.

CONCLUSIONS

Both the low rate of incidental prostate cancer in specimens with absent to focal HG-PIN and the high rate of cancer in specimens with multifocal or extensive HG-PIN suggest that HG-PIN is a marker for concurrent prostate cancer and that the risk of concurrent prostate cancer is related to the volume of HG-PIN in the prostate gland.

Incidence and clinical significance of high-grade prostatic intraepithelial neoplasia in TURP specimens

OBJECTIVES

To determine the incidence and clinical significance of high-grade prostatic intraepithelial neoplasia (PIN) in specimens obtained from transurethral resection of the prostate (TURP).

METHODS

All TURP specimens accessioned to the general surgical pathology service of the Johns Hopkins Hospital (JHH) from March 1984 through December 1987 that did not contain adenocarcinoma of the prostate were reviewed for the presence of high-grade PIN (PIN 2 and PIN 3). These cases were supplemented with cases from the consultation files of the JHH, the Armed Forces Institute of Pathology, and the University of Michigan Hospitals. In total, 85 cases of high-grade PIN in TURP specimens were identified.

RESULTS

The mean age of the patients at the time of TURP was 70 years and the median age was 71 years (range 50 to 89). Sixty-three patients (74%) were 65 years of age or older, 45 patients (53%) were at least 70 years of age, and 14 patients (16%) were 60 years of age or younger. Adenocarcinoma of the prostate was discovered in 9 (22%) of 41 patients with follow-up information. Based on material from JHH, the incidence of high-grade PIN was 2.3% in all TURP specimens and 3.2% in those without invasive carcinoma.

CONCLUSIONS

High-grade PIN on TURP is relatively uncommon and is diagnosed in an elderly population. Patients with high-grade PIN on TURP appear to be at increased risk of developing prostatic carcinoma, although not to the same degree as patients with high-grade PIN on needle biopsy.

Molecular biology of prostatic intraepithelial neoplasia

High-grade PIN is the most likely precursor of prostatic adenocarcinoma, according to virtually all available evidence to date. The clinical importance of recognizing PIN is based on its strong association with prostatic carcinoma. PIN has a high predictive value as a marker for adenocarcinoma. Its identification in biopsy specimens of the prostate warrants further search for concurrent invasive carcinoma. PIN is associated with progressive abnormalities of phenotype and genotype intermediate between normal prostatic epithelium and cancer, indicating impairment of cell differentiation and regulatory control with advancing stages of prostatic carcinogenesis. There is progressive gain or loss of a wide variety of biomarkers, including morphometric markers, differentiation markers, stromal markers, growth factors and associated receptors, oncogenes, tumor suppressor genes, and chromosomes. Abnormalities in expression of most biomarkers are amplified in the progression from high-grade PIN to localized cancer, metastatic cancer, and hormone-refractory cancer. Oncogenesis of prostatic carcinoma probably occurs through the selection of several genetic changes, each modifying the expression or function of genes controlling cell growth and differentiation. Further studies are needed to evaluate the function and prognostic value of oncogene expression in the normal, preneoplastic, and neoplastic prostate.

Numerical chromosomal changes in high-grade prostatic intraepithelial neoplasia (PIN) and concomitant invasive carcinoma

Prostatic intraepithelial neoplasia (PIN) is regarded as a precursor lesion of at least some prostatic cancers. Using interphase cytogenetics, an in situ hybridization technique with chromosome specific probes, we investigated 15 prostatectomy specimens containing both invasive carcinoma and PIN for the presence of numerical changes of chromosomes 7, 8, 10, 17 and X. The results were correlated with tumor stage and Gleason grade as well as with morphological features of PIN. Of the 15 carcinomas, four were disomic, five displayed at least focal chromosomal gains and six were found to be aneusomic. A non-disomic chromosomal status correlated well with a higher tumor stage and grade. Although the majority of PIN glands showed an eusomy, focal chromosomal gains within single glands or parts of a gland could be observed in 12 of the 15 cases. All but one specimen with non-disomic carcinomas also harboured areas of PIN with numerical chromosomal aberrations, often laying directly adjacent to tumorous glands. Additionally, focal non-disomies of PIN could also be detected in two cases with eusomic cancer. With regard to numerical changes in PIN and cancer, no significant preponderance could be observed for the five chromosomes tested. We conclude that numerical chromosomal aberrations are a frequent, but mostly focal event in PIN. This karyotypic instability is further evidence for the premalignant nature of this lesion.

Pre-neoplastic lesions of the prostate

Acinar carcinoma of the prostate is the third most frequently registered cancer and its incidence is expected to increase as life expectancy increases. Consequently, there have been attempts to introduce possible screening programmes for early detection of prostatic carcinoma. In this context the histopathologist has a role in that potential pre-neoplastic lesions have to be recognized. Two such pre-neoplastic lesions in the prostate are adenomatous hyperplasia and prostatic intraepithelial neoplasia. In this article the histological features of these lesions, their differential diagnosis and their pre-malignant potential are reviewed.

Interphase cytogenetics of prostatic adenocarcinoma and precursor lesions: analysis of 25 radical prostatectomies and 17 adjacent prostatic intraepithelial neoplasias

Twenty-five radical prostatectomy specimens were screened for the presence of numerical chromosome changes within the adenocarcinoma as well as 17 adjacent prostatic intraepithelial neoplasias (PIN) by means of interphase in situ hybridization (ISH) to routinely processed tissue sections. To this end a defined alfoid repetitive DNA probe set was used, specific for the centromeres of chromosomes 1, 7, 8, 10, 15, and Y. The cytogenetic information was correlated with histopathological and clinical features as well as with DNA ploidy. Numerical aberrations of at least one chromosome were shown in 13 of 25 cases (52%). Alterations of chromosome 8 and loss of the Y chromosome were the most frequent findings (both 20%), followed by loss of chromosomes 15 (16%) and 10 (12%). Gain of chromosome 7 was seen in 8% of cases. No aberrations of chromosomes 7, 8, 10, and 15 were found in the adjacent PIN lesions, whereas loss of the Y chromosome in both PIN and tumor occurred in two cases. Also, (low level) aneuploidy was observed in 76% of these PIN lesions. Ploidy of the carcinomas as assessed by ISH correlated well with ploidy measured by DNA flow cytometry (FCM; P < 0.02). Due to the more specific correspondence between ISH and tumor pathology, pathologic grade correlated with ISH aneuploidy (P < 0.05), whereas FCM ploidy did not. Furthermore, genetic heterogeneity within a tumor was seen, as judged by the focal appearance of chromosomal aberrations. Chromosomal alterations occurred in all grades and stages, although loss of chromosome 10, gain of chromosome 7, and aberrations of chromosome 8 tended to predominate in more advanced cancers.

Fibroblast subpopulations as accelerators of tumor progression: the role of migration stimulating factor

Tumor progression is a relatively indolent process, with many years commonly intervening between the inception of an initiating genetic lesion and the development of overt malignant disease. We suggest that the perturbation of normal epithelial-mesenchymal interactions caused by the inappropriate presence of fibroblast subpopulations displaying various 'fetal-like' phenotypic characteristics may significantly alter the kinetics of tumor progression and hence enhance susceptibility to cancer development. In this communication, we review our own data indicating the presence of fetal-like fibroblasts in cancer patients and put these observations in the context of similar published reports. We then discuss our interpretation of these findings, emphasising the possible direct involvement of fetal-like fibroblasts in cancer pathogenesis and putting forward an epigenetic 'clonal modulation' model to account for their presence in cancer patients.

Phenotypic heterogeneity in breast fibroblasts: functional anomaly in fibroblasts from histologically normal tissue adjacent to carcinoma

Histologically normal breast tissue was obtained from women undergoing surgery for benign breast lesions (n = 12) and mammary carcinomas (n = 15). Four fibroblast subpopulations (FI, FII, FIII and FIV) were isolated from these specimens by differential digestion and centrifugation. FI cells were the first to be released from the tissue digest and consequently assumed to be derived from the interlobular stroma; FIV fibroblasts were tightly associated with the epithelial organoids and are therefore believed to be of intralobular origin. These cells were characterised in terms of their migratory phenotype (classified as either foetal- or adult-like) and the production of motility factors according to previously described techniques. FI fibroblasts obtained from patients with benign breast lesions displayed a foetal migratory phenotype (10/11) and secreted detectable quantities of motility factors (11/11). In contrast, none of the FIV fibroblasts (0/10) obtained from these same patients displayed a foetal-like migratory phenotype or secreted motility factors. In the case of fibroblasts obtained from cancer patients, both FI (13/13) and FIV (13/13) fibroblasts displayed a foetal-like migratory phenotype and secreted motility factors. Fibroblasts were also derived from skin (n = 12) and breast fat tissue (n = 4) of certain patients. In agreement with our previously published observations, skin fibroblasts obtained from non-cancer and cancer patients also differed in terms of their migratory behaviour: none of the skin fibroblast lines (0/5) obtained from non-cancer patients were foetal-like, compared to 3/7 lines from cancer patients. All fat-derived fibroblasts (1 non-cancer and 3 cancer patients) were also foetal-like. Our results indicate (i) functional heterogeneity between FI and FIV fibroblasts of normal breast, and (ii) the presence of functionally aberrant (i.e., foetal-like) FIV fibroblasts in histologically normal breast tissue adjacent to a carcinoma.

Comparison of DNA ploidy in prostatic intraepithelial neoplasia and invasive carcinoma of the prostate: an image cytometric study

Prostatic intraepithelial neoplasia (PIN) is regarded as the most important premalignant lesion of prostatic epithelium. The aim of this investigation was to find clues to formal pathogenesis of prostatic cancer. For this purpose DNA ploidy (determined by means of image cytometry [ICM] using 4-microns-thick Feulgen-stained paraffin sections) of PIN and invasive carcinoma was compared. Prostatic tissue of 72 patients (mean age, 67.5 years; 82 areas with carcinoma and 71 areas with PIN) was examined. In 44 cases PIN and carcinoma were coexistent in the same prostates, the PIN grade being high in 77% of these cases (P < .05). In higher-grade PIN and higher-grade carcinoma the c-values, 2.5c-exceeding-rate, and aneuploidy rate increased (P < .01). Carcinomas associated with diploid PIN (either low or high grade) showed diploidy and aneuploidy in an equal number of cases, whereas 70% of aneuploid PIN cases (all high grade) were associated with aneuploid invasive carcinomas (P < .01). Conversely, in 71% of the cases with aneuploid carcinoma the coexistent PIN (either low or high grade) was diploid. Our findings show that aneuploidy can be acquired at a preinvasive stage of carcinogenesis in the prostate and suggest that aneuploid high-grade PIN might be regarded as a precursor of some but not all aneuploid prostatic carcinomas. Image cytometry analysis seems to be a promising method for further subclassification of high-grade PIN lesions into groups with putatively lower or higher risk. However, further investigation is necessary to confirm the clinical importance of these results.