Activation of c-MET induces a stem-like phenotype in human prostate cancer.

Prostate cancer consists of secretory cells and a population of immature cells. The function of immature cells and their mutual relation with secretory cells are still poorly understood. Immature cells either have a hierarchical relation to secretory cells (stem cell model) or represent an inducible population emerging upon appropriate stimulation of differentiated cells. Hepatocyte Growth Factor (HGF) receptor c-MET is specifically expressed in immature prostate cells. Our objective is to determine the role of immature cells in prostate cancer by analysis of the HGF/c-MET pathway.Gene-expression profiling of DU145 prostate cancer cells stimulated with HGF revealed induction of a molecular signature associated with stem cells, characterized by up-regulation of CD49b, CD49f, CD44 and SOX9, and down-regulation of CD24 ('stem-like signature'). We confirmed the acquisition of a stem-like phenotype by quantitative PCR, FACS analysis and Western blotting. Further, HGF led to activation of the stem cell related Notch pathway by up-regulation of its ligands Jagged-1 and Delta-like 4. Small molecules SU11274 and PHA665752 targeting c-MET activity were both able to block the molecular and biologic effects of HGF. Knock-down of c-MET by shRNA infection resulted in significant reduction and delay of orthotopic tumour-formation in male NMRI mice. Immunohistochemical analysis in prostatectomies revealed significant enrichment of c-MET positive cells at the invasive front, and demonstrated co-expression of c-MET with stem-like markers CD49b and CD49f.In conclusion, activation of c-MET in prostate cancer cells induced a stem-like phenotype, indicating a dynamic relation between differentiated and stem-like cells in this malignancy. Its mediation of efficient tumour-formation in vivo and predominant receptor expression at the invasive front implicate that c-MET regulates tumour infiltration in surrounding tissues putatively by acquisition of a stem-like phenotype.

Cysteine-rich secretory protein 3 and ß-microseminoprotein on prostate cancer needle biopsies do not have predictive value for subsequent prostatectomy outcome.

OBJECTIVES: • To investigate whether cysteine-rich secretory protein 3 (CRISP-3) and/or ß-microseminoprotein (ß-MSP) expression in diagnostic prostate needle biopsies have predictive value for prostate cancer (PC) on radical prostatecomy (RP). • To evaluate their potential clinical implementation in a preoperative setting. PATIENTS AND METHODS: • In total, 174 participants from the European Randomized Study of Screening for Prostate Cancer, Rotterdam section, treated by RP for PC were included in the present study. • CRISP-3 and ß-MSP immunohistochemistry was performed on corresponding diagnostic needle biopsies. • Outcome was correlated with clinicopathological parameters (prostate-specific-antigen, PSA; number of positive biopsies; Gleason score, GS; pT-stage; surgical margins at RP) and significant PC at RP (pT3/4, or GS > 6, or tumour volume ≥ 0.5 mL) in the total cohort (n= 174) and in a subgroup with low-risk features at biopsy (PSA ≤ 10 ng/ml, cT ≤ 2, PSA density <0.20 ng/mL/g, GS < 7 and ≤ 2 positive biopsy cores; n= 87). RESULTS: • ß-MSP and CRISP-3 expression in PC tissue was heterogeneous, with variable staining intensities occurring in the same tissue specimen. • High expression of ß-MSP significantly correlated with GS < 7 at RP; it was not a predictor for significant PC at RP neither in the total group (n= 174; odds ratio, OR, 0.319; 95% confidence interval, CI, 0.060-1.695; P= 0.180), nor in the low-risk group (n= 87; OR, 0.227; 95% CI, 0.040-1.274; P= 0.092). • CRISP-3 expression was not related to clinicopathological parameters, and did not predict significant PC at RP in the total group (n= 174; OR, 1.056; 95% CI, 0.438-2.545; P= 0.904) or the low-risk group (n= 87; OR, 1.856; 95% CI, 0.626-5.506; P= 0.265). CONCLUSIONS: • High ß-MSP expression correlated with low GS in subsequent RP specimens, supporting the view that ß-MSP exerts a tumour-suppressive effect. • No significant prognostic value of ß-MSP or CRISP-3 in prostate needle biopsies for significant PC at RP was found. • ß-MSP or CRISP-3 do not have additional value in the therapeutic stratification of patients with PC.

The value of EZH2, p27(kip1), BMI-1 and MIB-1 on biopsy specimens with low-risk prostate cancer in selecting men with significant prostate cancer at prostatectomy.

OBJECTIVE: To assess the additional prognostic value of the molecular markers EZH2, MIB-1, p27(kip1) and BMI-1 on needle biopsies from men with low-risk prostate cancer, as this disease in needle biopsies shows a heterogeneous clinical outcome, and while it is known that the expression of these tissue markers is predictive of the clinical outcome after radical prostatectomy (RP) their value in prostate biopsies is largely unknown. PATIENTS AND METHODS: The study included men participating in a screening study, diagnosed with low-risk prostate cancer and subsequently treated with RP. Immunohistochemical staining for EZH2, MIB-1, p27(kip1) and BMI-1 on the needle biopsies were (semi)quantitatively scored and expression levels were related to significant disease at RP. Clinical low-risk prostate cancer was defined as a prostate-specific antigen (PSA) level of < or =10 ng/mL, clinical T-stage < or =2, biopsy Gleason score < or =6, a PSA density of <0.20 ng/mL/g and two or fewer positive cores. Significant PC at RP was defined as presence of any of extracapsular extension, Gleason pattern 4/5, or tumour volume > or =0.5 mL. RESULTS: In all, 86 biopsy specimens were included; there was high EZH2 expression (>1.0%) in 42% and a low p27(kip) expression (<90%) in 63%. Significant disease was present in 44 (51%) RP specimens. A high EZH2 (odds ratio 3.19, P = 0.043) and a low p27(kip1) (4.69, P = 0.036) were independent predictors for significant prostate cancer at RP. CONCLUSIONS: The determination of EZH2 and p27(kip1) on diagnostic needle biopsies supports the selection of men with indolent prostate cancer at RP. Especially p27(kip1) could improve the pretreatment risk assessment of patients with low-risk prostate cancer.

Array comparative genomic hybridization, expression array, and protein analysis of critical regions on chromosome arms 1q, 7q, and 8p in adenocarcinomas of the gastroesophageal junction.

Survival rates of adenocarcinomas of the gastroesophageal junction (GEJ) are low, because these tumors are generally in an advanced stage by the time they are detected. Chromosomal regions 1q32, 7q21, and 8p22 display critical alterations in GEJ cancers; however, the genes underlying alterations in these genomic areas are largely unknown. To delineate overexpressed genes, we performed array comparative genomic hybridization (aCGH) and mRNA expression analysis of 15 GEJ adenocarcinoma samples using a fine-tiling cDNA array covering chromosome segments 1q31.3~q41 (193.9-215.8 Mb: 21.9 Mb), 7q11.23~q22.1 (72.3-103.0 Mb: 30.7 Mb), and 8p23.1~p21.3 (11.1-20.7 Mb: 9.6 Mb). Based on a mRNA overexpression criterion, 11 genes were selected: ELF3 and SLC45A3 on 1q; CLDN12, CDK6, SMURF1, ARPC1B, ZKSCAN1, MCM7, and COPS6 on 7q; and FDFT1 and CTSB on 8p. The protein expression levels were subsequently determined by immunohistochemical analysis of the cancer samples. There was a significant correlation between genomic amplification, mRNA, and protein expression or overexpression for CDK6, a cell cycle regulator on 7q21.2 (92.1 Mb; P<0.01); other genes showed less stringent associations. In conclusion, using a straightforward approach we constructed a targeted gene profile for GEJ adenocarcinomas.

Immunohistochemical evaluation of a panel of tumor cell markers during malignant progression in Barrett esophagus.

Histopathologic grading of dysplasia in Barrett esophagus (BE) shows substantial interobserver and intraobserver variation. We used immunohistochemical analysis with a set of tumor cell markers, ie, epidermal growth factor receptor (EGFR), ERBB2 (HER2/neu), MYC, CDKN2A (p16), SMAD4, MET, CCND1 (cyclin D1), CTNNB1 (beta-catenin), and TP53 (p53), in histologic sections of endoscopic biopsies of 86 patients with BE in various stages of neoplastic progression. The markers, except SMAD4, were scored as 0 (<1% of cells stained), 1 (1%-25%), 2 (26%-50%), or 3 (>50%). All markers, except EGFR, showed a significant trend for immunohistochemical protein overexpression during malignant progression in BE (P <.01). When the successive stages along the metaplasia-low-grade dysplasia (LGD)-high-grade dysplasia (HGD)-adenocarcinoma axis were compared, protein overexpression of beta-catenin separated LGD from metaplasia, whereas protein overexpression of cyclin D1 and p53 discriminated HGD from LGD (all P <.001). beta-Catenin can be helpful for a diagnosis of LGD in BE, although it stains positively in a subset only, whereas p53 remains an appropriate marker to define HGD. In case of doubt, cyclin D1 can be added to separate LGD from HGD in BE.

Wnt pathway-related gene expression during malignant progression in ulcerative colitis.

Long-standing ulcerative colitis (UC) has been associated with a high risk of developing colonic adenocarcinoma. Importantly, both low- and high-grade dysplasia are strongly related to the presence or development of malignancy. The canonical Wnt/beta-catenin signaling pathway is of crucial importance in cancer development and progression, but its role in UC-related carcinogenesis remains to be determined. We evaluated the immunolabeling patterns of beta-catenin, as well as the products of Wnt-associated cancer genes E-cadherin, cyclin D1 and c-myc, along the dysplasia-carcinoma pathway in UC. For this purpose, immunohistochemistry (IHC) was performed on 18 adenocarcinomas and 17 dysplasias, derived from 21 patients. We found that intracellular beta-catenin accumulation, the hallmark of Wnt signaling activation, is observed in dysplasia, together with enhanced labeling of nuclear protein cyclin D1 and reduction of membranous labeling of E-cadherin. c-myc displayed moderate immunolabeling in the (pre)malignant lesions. Thus, the Wnt pathway is activated in early stages of malignant progression in UC. Furthermore, upregulation of the oncogene cyclin D1 and downregulation of tumor suppressor E-cadherin also occurs in the (pre)neoplastic state. This may contribute to the high potential for malignant degeneration of dysplasia in UC-related colitis.

Chromosomal and microsatellite instability of adenocarcinomas and dysplastic lesions (DALM) in ulcerative colitis.

Longstanding ulcerative colitis (UC) is associated with a high risk of developing UC-related colonic adenocarcinoma (UCC). These carcinomas originate from nonadenomatous dysplastic regions referred to as dysplasia associated lesion or mass (DALM). We evaluated chromosomal and microsatellite instability (MSI) in 21 DALM/UCCs. Chromosomal instability was determined by high-resolution array comparative genomic hybridization with a 3500-element BAC-PAC array. MSI was assessed with markers BAT25 and BAT26 and by immunohistochemical analysis of mismatch repair genes. Comparative genomic hybridization revealed frequent losses of array clones (>20% of tumors) at chromosome arms 4p, 5q, and 18q, frequent gains of array clones (>20% of tumors) were found at 1q, 5p, 6p, 7p, 7q, 8p, 8q, 11p, 11q, 12q, 14q, 17q, 19q, 20p, and 20q. The pattern of alterations is dominated by gains on 5p and 20q with loss of 4p, all of which were already present in a patient with carcinoma in situ. Immunohistochemical analysis of mismatch repair genes MLH1, PMS2, MSH2, and MSH6 showed negative immunostaining in 1 neoplasm (5%). MSI of BAT25 and BAT26 was seen in 3 tumors (14%) including the neoplasm with aberrant immunostaining. In conclusion, we constructed a genomic profile of DALM/UCC including several novel genetic alterations. Further, we found a low percentage of MSI. Thus, DALM/UCCs display profound chromosomal instability, but this is not associated with concurrent MSI.

Genomic analysis of a case of multifocal adenocarcinoma in ulcerative colitis.

Long-standing ulcerative colitis is associated with an elevated risk of developing colonic adenocarcinoma. A very limited group of patients present with multiple synchronous cancers. This could be due to either a multifocal presentation of the same neoplastic clone or different tumors arising in a large area of polyclonal dysplastic colonic mucosa ("field cancerization"). Here, we describe a patient with long-standing colitis and three different tumors in the rectosigmoid part of the large bowel. Clonal evaluation of the lesions was performed by array-based comparative genomic hybridization. These three neoplasms showed a comparable pattern of genomic alterations characterized by gains of chromosomes 12, 13, and 20. Noteworthy, dysplastic mucosa distal to the three cancers displayed a completely different pattern of genomic changes indicating that different cell lineages were present. In addition, all three carcinomas were microsatellite stable and revealed identical immunoprofiles for several cancer-associated genes. We conclude that these three multifocal tumors must have originated from the same preneoplastic lineage.

Array-based genomic analysis of screen-detected Gleason score 6 and 7 prostatic adenocarcinomas.

BACKGROUND: Prostate cancer is known for its heterogeneous histological appearance. It is currently not clear whether this histological heterogeneity is also reflected in the genomic composition of a tumor. MATERIALS AND METHODS: The cancer DNA's were retrieved from the European Randomized Study of Screening for Prostate Cancer section Rotterdam (ERSPC). Tumors with volumes 1.0-1.5 ml and a Gleason score of 3+3 or 3+4 were selected. Comparative genomic hybridization with a 3500-element BAC array was used to detect differences in the genetic content of Gleason patterns 3 and 4. RESULTS: A total of 1155 gains and 583 losses were discriminated in 10 G3 areas; 768 gains and 497 losses were detected in 7 G4 regions. Frequent losses included chromosome arms 6q, 8p and 13q, while frequent gains were seen on 7q and 8q. There were no significant differences between Gleason patterns 3 and 4, or between Gleason grades within one cancer. CONCLUSION: Histological heterogeneity, defined by Gleason grades 3 and 4, does not have a genomic counterpart. Furthermore, these asymptomatic screen-detected prostate carcinomas have genetic signatures comparable with those commonly seen in symptomatic cancers.

Genomic analysis of early adenocarcinoma of the esophagus or gastroesophageal junction: tumor progression is associated with alteration of 1q and 8p sequences.

Early (T1 stage) adenocarcinoma of the esophagus or gastroesophageal junction is a potentially curable disease. We analyzed the genomic spectra of 33 early neoplastic lesions after subdividing the tumors into six depths of invasion (T1-mucosal, m1-m3; T1-submucosal, sm1-sm3). Two subgroups were defined, T1m1-sm1 (n = 18) and T1sm2-sm3 (n = 15). The latter group is associated with frequent lymphatic spread and a high percentage of local and/or distant recurrence. Comparative genomic hybridization with a genomewide 3,500-element BAC-PAC array revealed a characteristic gastroesophageal adenocarcinoma pattern of changes, with losses on chromosome arms 4pq, 5q, 8p, 9p, 17p, and 18q and gains on 1q, 6p, 7pq, 11q, 15q, 17q, and 20pq. However, when the two groups were compared, the following BAC clones showed significantly more alterations in the T1sm2-sm3 group: RP11-534L20 (1q32.1) and RP11-175A4 (6p21.32), showing gains, and RP11-356F24, RP11-433L7, and RP11-241P12 (all at 8p), showing losses. Gain of RP11-534L20 (1q32.1) and loss of RP11-433L7 (8p22) were associated not only with a recurrence-free period (P = 0.0007 and 0.007, respectively), but also with regional lymphatic dissemination (P = 0.005 and 0.003, respectively). These DNA clones can be considered genomic markers for the aggressive behavior of early esophageal and gastroesophageal junction adenocarcinoma.

Genomic analysis of Barrett's esophagus after ablative therapy: persistence of genetic alterations at tumor suppressor loci.

Barrett's esophagus (BE) is a major predisposing factor for the development of esophageal adenocarcinoma. Current strategies for treatment of BE, both dysplastic and nondysplastic, include photodynamic therapy (PDT) and argon plasma coagulation (APC). However, the effect of ablative therapy at the genetic level is unclear. We performed loss of heterozygosity (LOH) analysis of BE in baseline and follow-up biopsy specimens from 21 patients with BE (17 male, 4 female) treated with PDT and/or APC. At baseline, 14 patients had intestinal metaplasia without dysplasia (MET), 4 low-grade dysplasia (LGD) and 3 high-grade dysplasia (HGD). LOH was assessed using a panel of 9 polymorphic markers for evaluation of the P53 gene on 17p, P16 on 9p, DCC and SMAD4 on 18q and the APC gene on 5q. The tissue specimens obtained at baseline (t = 0) were analysed, as well as the first (t = 1; mean interval: 4 months) and last (t = 2; mean interval: 8 months) available biopsy with residual or recurrent BE after ablation. At t = 0, allelic loss was detected of 5q in 27%, 9p in 56%, 17p in 31% and 18q in 6% of informative cases. At t = 1 (18 patients with persistent MET and 3 with LGD) and at t = 2 (8 MET, 2 LGD), the LOH patterns were not statistically different from t = 0. Further, multiple genetic lineages before and after therapy were detected in 15 cases illustrating the multiclonal nature of BE. We conclude that recurrent and/or persistent BE after ablative therapy still contains genetic alterations associated with malignant progression to cancer. Therefore, the goal of treatment should be the complete elimination of Barrett's mucosa.

Cell biological evaluation of liver cell carcinoma, dysplasia and adenoma by tissue micro-array analysis.

The clinical and morphological definition of hepatocellular carcinoma (HCC), dysplasia and adenoma suffers from a lack of biological understanding. This is especially important in the histomorphological diagnosis of nodular liver lesions in needle biopsies. Therefore, we constructed a liver tissue micro-array (TMA) and evaluated 48 HCCs, 46 dysplasias, 8 adenomas, 20 cirrhotic specimens and 28 normal liver samples derived from 68 patients. Protein (over)expression by tumor suppressor genes p16, p53 and Rb1 was assessed by immunohistochemistry, the proliferative capacity was examined by immunostaining of Ki67. Further, DNA ploidy status (hyperdiploidy) was measured by fluorescent in situ hybridization (FISH) with a chromosome 1-specific repetitive DNA probe. An abnormal chromosome 1 number, i.e. the percentage of hyperdiploid cells, was 11.0, 13.7, 16.1, 23.7 and 31.3 for normal liver samples, adenomas, cirrhosis, dysplasias and HCCs, respectively. A significant difference was found for HCC versus cirrhosis (P = 0.024) or adenoma (P = 0.033), a trend (borderline significance) was seen for dysplasia versus cirrhosis (P = 0.094). Immunohistochemical protein localisation of p53 and Rb1, as well as Ki67 indicating proliferation, was clearly higher in HCC than in cirrhosis or dysplasia (all P < 0.001). Proliferation was also higher in HCC than in adenoma (P = 0.025), whereas a trend (borderline significance) was observed for Rb1 overexpression (P = 0.063). These data suggest that in the liver cell dysplasia-carcinoma pathway, changes in ploidy are followed by increased proliferation and cell biological perturbations involving p53 and Rb1. Adenomas can be distinguished from carcinomas, but not from dysplasias, based on ploidy and proliferation characteristics.

Allelic imbalance on distal 7q (7q36.1-q36.3) in gastric cardia and oesophageal (Barrett's) adenocarcinoma.

BACKGROUND: Oesophageal (Barrett's) and gastric cardia adenocarcinomas are cancers arising at and around the gastro-oesophageal junction. The prognosis is poor, since detection is usually at a late stage and metastatic spread occurs early. MATERIALS AND METHODS: We investigated the 7q region with a set of 5 polymorphic markers spanning 7q36.1-q36.3 in 33 Barrett-related carcinomas. In addition, 40 gastric cardia cancers were investigated to compare the pattern of imbalance at these loci. RESULTS: Overall, the number of allelic loss was higher in Barrett's cancers than in gastric cardia carcinomas (p=0.04). In Barrett's adenocarcinomas, imbalance varied from 28% to 45% (of informative cases) with the highest prevalence at marker D7S483. In gastric cardia cancers, loss ranged from 12% to 27% (of informative cases), being most frequent at marker D7S3037. The difference between oesophageal and gastric adenocarcinomas was highest for polymorphic marker D7S483 (p=0.05). CONCLUSION: Marker D7S483 can aid in discriminating oesophageal (Barrett's) and gastric cardia carcinomas. Further, this region possibly harbours cancer gene(s) involved in Barrett-related adenocarcinomas.

Molecular evaluation of ablative therapy of Barrett's oesophagus.

Barrett's oesophagus is a major risk factor for developing oesophageal adenocarcinoma. Ablation by argon plasma coagulation (APC) and photodynamic therapy (PDT) is currently under investigation for the removal of metaplastic and dysplastic Barrett's oesophagus. This study examined the effect of ablative therapy on Barrett's oesophagus at cell-cycle and genetic levels. The premalignant potential of residual or recurring Barrett's oesophagus was assessed by p53 immunohistochemistry, Ki67-related proliferative capacity, and DNA ploidy status (ie an abnormal chromosome 1 number) as measured by interphase in situ hybridization. Twenty-nine patients with Barrett's oesophagus (23 male and 6 female, mean age 58 years, mean length of Barrett's oesophagus 4 cm) were treated with APC or PDT. Intestinal metaplasia without dysplasia was present in 16 patients, low-grade dysplasia in five, and high-grade dysplasia in eight patients. Biopsy samples were obtained at regular intervals (mean follow-up 20 months, range 6-36 months). One month after the first ablation, Barrett's oesophagus was no longer identified, either endoscopically or histologically, in nine patients (32%). At this time point, significant down-grading was achieved for abnormal chromosome 1 numbers (p = 0.020) and Ki67-defined proliferation (p = 0.002). Patients with residual Barrett's oesophagus were additionally treated with APC, resulting in the elimination of Barrett's oesophagus in 76% of all patients. However, at the last follow-up endoscopy, metaplasia without dysplasia was still present in five patients, and low- and high-grade dysplasia were each present in one patient. An abnormal chromosome 1 number and p53 protein overexpression were detected only in the high-grade dysplastic lesion, but increased proliferation was still present in the majority of these persisting cases. Although endoscopic removal of Barrett's oesophagus by ablative therapies is possible in the majority of patients, histologically complete elimination cannot be achieved in all cases. Persistent Barrett's oesophagus may still harbour molecular aberrations and must therefore be considered still to be at risk of progression to adenocarcinoma.

Whole genome scanning identifies genotypes associated with recurrence and metastasis in prostate tumors.

Prostate cancer is the most commonly diagnosed non-cutaneous neoplasm among American males and is the second leading cause of cancer-related death. Prostate specific antigen screening has resulted in earlier disease detection, yet approximately 30% of men will die of metastatic disease. Slow disease progression, an aging population and associated morbidity and mortality underscore the need for improved disease classification and therapies. To address these issues, we analyzed a cohort of patients using array comparative genomic hybridization (aCGH). The cohort comprises 64 patients, half of whom recurred postoperatively. Analysis of the aCGH profiles revealed numerous recurrent genomic copy number aberrations. Specific loss at 8p23.2 was associated with advanced stage disease, and gain at 11q13.1 was found to be predictive of postoperative recurrence independent of stage and grade. Moreover, comparison with an independent set of metastases revealed approximately 40 candidate markers associated with metastatic potential. Copy number aberrations at these loci may define metastatic genotypes.

Evaluation of genetic patterns in different tumor areas of intermediate-grade prostatic adenocarcinomas by high-resolution genomic array analysis.

Prostate cancer is known for its highly heterogeneous histological appearance. Data concerning the cytogenetic content of areas with different histology are sparse. We have genetically evaluated 10 prostatic adenocarcinomas with intermediate histopathological grades (Gleason score 7) that showed two distinctive growth patterns with different pathologies, that is, Gleason grades 3 and 4 (G3 and G4). The G3 and G4 tumor specimens were taken from spatially separated regions within the cancer mass. Array-based comparative genomic hybridization (aCGH) was performed to obtain genotypes from the 10 pairs of G3 and G4 cancer areas. The cancer DNAs were retrieved from formalin-fixed and paraffin-embedded tissues allowing optimal recognition and selection of target cells. A genome-wide 2,400-element BAC array that provided high-resolution detection of both deletions and amplifications was used. In the 20 G3 and G4 areas, 252 genomic aberrations (88 gains, 164 deletions) were noted, of which 86 were concurrent in G3 and G4 areas (34% overlap). Ninety-five of the 252 alterations were defined by a single BAC clone (54 gains, 41 deletions). Overlapping changes were more frequent for deletions (46%) than for gains (13%). Frequent coinciding deletions (> or = 20% of tumors) were seen on 8p (60%), 6q (30%), 1p (20%), 2q (20%), proximal 8q (20%), 10q (20%), 13q (20%), 16q (20%), and 18q (20%). A frequent overlapping gain (> or = 20% of tumors) was detected on distal 13q (20%). The patterns of imbalance could be found to coincide in the G3 and G4 areas of the majority of cancers. Array-based CGH can be used as a tool for the evaluation of genetic patterns in prostate cancer.

Genetic evaluation of localized prostate cancer in a cohort of forty patients: gain of distal 8q discriminates between progressors and nonprogressors.

Over-representation of sequences on chromosome 7 and 8 have been reported to be associated with aggressive behavior of prostate cancer. In this study we have performed a molecular cytogenetic survey by comparative genomic hybridization of a cohort of 40 prostate cancer patients, consisting of 20 progressors and 20 nonprogressors, after radical surgery for localized adenocarcinoma. Progression was defined as a biochemical relapse, ie, an elevation in prostate-specific antigen level in the serum. The mean follow-up after prostatectomy for the progressor group was 10.6 years, for the nonprogressor group, 9.1 years. Using comparative genomic hybridization, we found that progressors harbored on average more aberrations than nonprogressors. Gains were especially more prominent among progressors (p < 0.05), whereas a statistical trend was detected for losses (p = 0.10). As a consequence we examined all chromosome arms separately. The frequencies of loss for areas known to be frequently deleted in prostate cancer, such as 6q, 8p, or 13q, were not different between the two groups. A tendency was observed for more frequent gain on 3q in the progressor group (p = 0.09). However, gain of 8q (minimal overlapping region at 8q24-qter) was significantly more frequent in the progressor group (p = 0.04). This biomarker retained its significance when adjusted for the factors age, tumor grade, tumor stage, resection margin status, and preoperative prostate-specific antigen level. In conclusion we have created a map of genetic changes in progressive and nonprogressive prostatic carcinomas. Importantly, the presence of gain of distal 8q markedly reduced the progression-free survival, suggesting a clinical role for 8q gain in assessing the malignant potential of localized prostatic adenocarcinoma.

High-resolution analysis of paraffin-embedded and formalin-fixed prostate tumors using comparative genomic hybridization to genomic microarrays.

We have used prostate cancer, the most commonly diagnosed noncutaneous neoplasm among men, to investigate the feasibility of performing genomic array analyses of archival tissue. Prostate-specific antigen and a biopsy Gleason grade have not proven to be accurate in predicting clinical outcome, yet they remain the only accepted biomarkers for prostate cancer. It is likely that distinct spectra of genomic alterations underlie these phenotypic differences, and that once identified, may be used to differentiate between indolent and aggressive tumors. Array comparative genomic hybridization allows quantitative detection and mapping of copy number aberrations in tumors and subsequent associations to be made with clinical outcome. Archived tissues are needed to have patients with sufficient clinical follow-up. In this report, 20 formalin-fixed and paraffin-embedded prostate cancer samples originating from 1986 to 1996 were studied. We present a straightforward protocol and demonstrate the utility of archived tissue for array comparative genomic hybridization with a 2400 element BAC array that provides high-resolution detection of both deletions and amplifications.