Chromosomal changes during development and progression of prostate adenocarcinomas

Performance of Indocyanine Green Fluorescence for Detecting Lymph Node Metastasis in Prostate Cancer: A Systematic Review and Meta-analysis

PURPOSE

The use of sentinel lymph node dissection in several cancers has been gaining attention with the emergence of indocyanine green fluorescence. We performed a meta-analysis to assess the diagnostic performance of indocyanine green fluorescence in detecting lymph node metastasis in prostate cancer patients.

METHODS

A literature search was conducted using PubMed, Cochrane Library, and SCOPUS on November 30, 2020, to identify eligible studies. Studies were eligible if they investigated the diagnostic performance of indocyanine green fluorescence before pelvic lymph node dissection in prostate cancer patients and reported the number of true positives, false positives, false negatives, and true negatives on lymph node-based analysis in comparison to histopathologic findings in the dissected specimen.

RESULTS

Our systematic review covered 11 studies published between 2011 and 2020, with 519 patients, and our meta-analysis included 9 studies with 479 patients. Based on lymph node analysis of indocyanine green fluorescence, the results showed pooled sensitivity and specificity at 0.75 (95% confidence interval [CI] 0.49 to 0.90) and 0.66 (95% CI 0.61 to 0.70), respectively. The diagnostic odds ratio was 6.0 (95%CI 2 to 21). Several lymphatic drainage routes also showed sentinel lymph nodes localized outside the ordinal pelvic lymph node template.

CONCLUSIONS

We noted relatively low diagnostic performance for lymph node metastasis, suggesting that indocyanine fluorescence may not currently be a viable alternative to pelvic lymph node dissection in prostate cancer patients. However, this technique shows novel lymphatic drainage routes and underscores the importance of lymph nodes not removed in ordinary dissection.

Molecular mechanisms involving prostate cancer racial disparity

Prostate cancer (PCa) is the second leading cause of cancer-related deaths in the United States. The African (AA) descent has greater incidence and mortality rates of PCa as compared to Caucasian (CA) men. While socioeconomic differences across racial groups contribute to disparity in PCa, increasing evidence points that genetic and molecular alterations play important roles in racial disparities associated with PCa. In this review, we focus on genetic and molecular influences that contribute to racial disparity between AA and CA men including: androgen and estrogen receptor signaling pathways, growth factors, apoptotic proteins, genetic, genomic and epigenetic alterations. Future translational studies will identify prognostic and predictive biomarkers for AA PCa and assist in the development of new targeted-therapies specifically for AA men with PCa.

Copy number variations of circulating, cell-free DNA in urothelial carcinoma of the bladder patients treated with radical cystectomy: a prospective study

The aim of the present study was to establish a rapid profiling method using multiplex ligation-dependent probe amplification (MLPA) and characterize copy number variations (CNV) in circulating, cell-free DNA (cfDNA) in 85 urothelial carcinoma of the bladder (UCB) patients treated with radical cystectomy (RC). MLPA was tested for the use of cfDNA extracted from serum and plasma by various commercial extraction kits. Eighteen probes served as reference to control denaturation, ligation and amplification efficiency. MLPA was exclusively suitable for cfDNA extracted from serum. Serum from 72 patients (84.7%) could be analyzed. Thirty-five patients (48.6%) had presence of CNV in cfDNA. The median CNV count in patients with presence of CNV was 2. Predominantly, CNV were located in the genes CDH1, ZFHX3, RIPK2 and PTEN in 15 patients (20.8%), 12 patients (16.7%), 9 patients (12.5%) and 7 patients (9.7%), respectively. CNV in TSG1, RAD21, KIAA0196, ANXA7 and TMPRSS2 were associated with presence of variant UCB histology (p = 0.029, 0.029, 0.029, 0.029, 0.043, respectively). Furthermore, CNV in miR-15a, CDH1 and ZFHX3 were associated with presence of incidental prostate cancer (p = 0.023, 0.003, 0.025, respectively). Patients with CNV in KLF5, ZFHX3 and CDH1 had reduced cancer-specific survival, compared to patients without CNV in these genes (pairwise p = 0.028, 0.026, 0.044, respectively). MLPA represents an efficient method for the detection of CNV among numerous genes on various chromosomal regions. CNV in specific genes seem to be associated with aggressive UCB biologic features and presence of incidental prostate cancer, and may have a negative impact on cancer-specific survival.

Molecular basis for prostate cancer racial disparities

Prostate cancer (PCa) remains the most common cancer in American men. African-American (AA) men continue to have higher PCa prevalence and mortality rates compared to men in other populations. In addition to socioeconomic factors and lifestyle differences, molecular alterations contribute to this discrepancy. We summarize molecular genetics research results interrelated with the biology of PCa racial disparity. Androgen and androgen receptor (AR) pathways have long been associated with prostate growth. Racial differences have also been found among variants of genes of the enzymes involved in androgen biosynthesis and metabolism. Growth factors and their receptors are a potential cause of the disparity in PCa. Recent molecular and biotechnological approaches in the field of proteomics and genomics will greatly aid the advancement of translational research on racial disparity in PCa, which may help, in finding new prognostic markers and novel therapeutic approaches for the treatment of PCa in AA.

Allele frequency of ABO blood group antigen and the risk of esophageal cancer

BACKGROUND

ABO blood group and risk of squamous cell carcinoma of esophagus have been reported by many studies, but there is no discipline that had provided association with the genotype and gene frequency by population statics.

METHODS

We conducted a case-control study on 480 patients with squamous cell carcinoma of the esophagus and 480 noncancer patients. ABO blood group was determined by presence of antigen with the help of monoclonal antibody. Chi-square test and odds ratio (OR) with 95% confidence intervals (CIs) were calculated by statistical methods, and gene frequencies were calculated by Hardy-Weinberg model.

RESULTS

We observed significant associations between ABO genotype and squamous cell carcinoma of esophagus. OR (95% CIs) was 1.69 (1.31-2.19) for presence of B antigen allele relative to its absence (P < 0.0001); in female subgroup OR (95% CIs) observed at 1.84 (1.27-2.65) was statistically significant (P = 0.001). SCC of esophagus shows significant difference in comparison to general population; blood group B is found to be higher in incidence (P = 0.0001). Increased risk of cancer was observed with absence of Rh antigen (P = 0.0001). Relatively increased gene frequency of q[B] allele is observed more significantly in female cancer patients (P = 0.003).

CONCLUSION

Statistically significant association between squamous cell carcinoma of the esophagus and ABO and Rh genotype is identified by this study. Sex and anatomical site of cancer also present with statistically significant relative association. However, larger randomised trials are required to establish the hypothesis.

Regulation of SRC kinases by microRNA-3607 located in a frequently deleted locus in prostate cancer

Genomic studies suggest that deletions at chromosome (chr) 5q region (particularly chr5q14-q23) are frequent in prostate cancer, implicating this region in prostate carcinogenesis. However, the genes within this region are largely unknown. Here, we report for the first time the widespread attenuation of miR-3607, an miRNA gene located at chr5q14 region, in prostate cancer. Expression analyses of miR-3607 in a clinical cohort of prostate cancer specimens showed that miR-3607 is significantly attenuated and low miR-3607 expression is correlated with tumor progression and poor survival outcome in prostate cancer. Our analyses suggest that miR-3607 expression may be a clinically significant parameter with an associated diagnostic potential. We examined the functional significance of miR-3607 in prostate cancer cell lines and found that miR-3607 overexpression led to significantly decreased proliferation, apoptosis induction, and decreased invasiveness. Furthermore, our results suggest that miR-3607 directly represses oncogenic SRC family kinases LYN and SRC in prostate cancer. In view of our results, we propose that miR-3607 plays a tumor-suppressive role in prostate cancer by regulating SRC kinases that in turn regulates prostate carcinogenesis. To our knowledge, this is the first report that: (i) identifies a novel role for miR-3607 located in a frequently deleted region of prostate cancer and (ii) defines novel miRNA-mediated regulation of SRC kinases in prostate cancer. Because SRC kinases play a central role in prostate cancer progression and metastasis and are attractive targets, this study has potential implications in the design of better therapeutic modalities for prostate cancer management.

Current significance of the finding of high grade prostatic intraepithelial neoplasia in the prostate biopsy

INTRODUCTION

High grade prostatic intraepithelial neoplasia (HGPIN) is regarded as a precursor of prostate cancer (PC). However, its relationship to cancer has changed throughout the literature, being currently poorly defined and remains controversial for urologists in their clinical practice. Because of his frequency and the impact on patient outcomes that the lack of consensus clinical attitude could carry out, it seems advisable to review the understanding of this disease.

OBJECTIVE

The aim of this literature review is to summarize the main features of this entity (histopathology, molecular, epidemiological) and evaluate their relationship with prostate adenocarcinoma, explaining the variation of incidence seen in the literature and the clinical significance of their finding.

MATERIAL AND METHODS

Review of the literature, based on the research and analysis of publications found in Pubmed with the words "prostate" and "intraepithelial neoplasms".

RESULTS

The HGPIN detection rate has increased to the extent that it has increased the number of punctures in prostate biopsies. With the current biopsy schemes (10-12 punctures), the detection rate of PC in repeat biopsies is similar in patients with and without isolated HGPIN. However, HGPIN multifocality predicts increased risk of PC detection in repeat biopsy.

CONCLUSION

HGPIN detection is common with current biopsy schemes. Its genetic relationship with PC is clear and its multifocality is the most important predictor factor of PC.

The genomic landscape of prostate cancer

Prostate cancer is a common malignancy in men, with a markedly variable clinical course. Somatic alterations in DNA drive the growth of prostate cancers and may underlie the behavior of aggressive versus indolent tumors. The accelerating application of genomic technologies over the last two decades has identified mutations that drive prostate cancer formation, progression, and therapeutic resistance. Here, we discuss exemplary somatic mutations in prostate cancer, and highlight mutated cellular pathways with biological and possible therapeutic importance. Examples include mutated genes involved in androgen signaling, cell cycle regulation, signal transduction, and development. Some genetic alterations may also predict the clinical course of disease or response to therapy, although the molecular heterogeneity of prostate tumors poses challenges to genomic biomarker identification. The widespread application of massively parallel sequencing technology to the analysis of prostate cancer genomes should continue to advance both discovery-oriented and diagnostic avenues.

CYP24A1 is an independent prognostic marker of survival in patients with lung adenocarcinoma

PURPOSE

The active form of vitamin D, 1α,25-dihydroxyvitamin D(3) (1,25-D(3)), exerts antiproliferative effects in cancers, including lung adenocarcinoma (AC). CYP24A1 is overexpressed in many cancers and encodes the enzyme that catabolizes 1,25-D(3). The purpose of our study was to assess CYP24A1 as a prognostic marker and to study its relevance to antiproliferative activity of 1,25-D(3) in lung AC cells.

EXPERIMENTAL DESIGN

Tumors and corresponding normal specimens from 86 patients with lung AC (stages I-III) were available. Affymetrix array data and subsequent confirmation by quantitative real time-PCR were used to determine CYP24A1 mRNA expression. A subsequent validation set of 101 lung AC was used to confirm CYP24A1 mRNA expression and its associations with clinical variables. The antiproliferative effects of 1,25-D(3) were examined using lung cancer cell lines with high as well as low expression of CYP24A1 mRNA.

RESULTS

CYP24A1 mRNA was elevated 8- to 50-fold in lung AC (compared to normal nonneoplastic lung) and significantly higher in poorly differentiated cancers. At 5 years of follow-up, the probability of survival was 42% (high CYP24A1, n = 29) versus 81% (low CYP24A1, n = 57) (P = 0.007). The validation set of 101 tumors showed that CYP24A1 was independently prognostic of survival (multivariate Cox model adjusted for age, gender, and stage, P = 0.001). A549 cells (high CYP24A1) were more resistant to antiproliferative effects of 1,25-D(3) compared with SKLU-1 cells (low CYP24A1).

CONCLUSIONS

CYP24A1 overexpression is associated with poorer survival in lung AC. This may relate to abrogation of antiproliferative effects of 1,25-D(3) in high CYP24A1 expressing lung AC.

The candidate oncogene CYP24A1: A potential biomarker for colorectal tumorigenesis

The main autocrine/paracrine role of the active metabolite of vitamin D(3), 1alpha,25-dihydroxyvitamin D(3) (1,25-D(3)), is inhibition of cell growth and induction of cell differentiation and/or apoptosis. Synthesis and degradation of the secosteroid occurs not only in the kidney but also in normal tissue or malignant extrarenal tissues such as the colon. Because 25-hydroxyvitamin D(3) 24-hydroxylase (CYP24A1) is considered to be the main enzyme determining the biological half-life of 1,25-D(3), we have examined expression of the CYP24A1 mRNA (by real-time RT-PCR) and protein (by immunohistochemistry) in normal human colon mucosa, colorectal adenomas, and adenocarcinomas in 111 patients. Although 76% of the normal and benign colonic tissue was either completely devoid of or expressed very low levels of CYP24A1, in the majority of the adenocarcinomas (69%), the enzyme was present at high concentrations. A parallel increased expression of the proliferation marker Ki-67 in the same samples suggests that overexpression of CYP24A1 reduced local 1,25-D(3) availability, decreasing its antiproliferative effect.

Molecular mechanisms involving prostate cancer racial disparity

African American (AA) men with prostate cancer (PCa) have worse disease, with a higher incidence, younger age and more advanced disease at diagnosis, and a worse prognosis, compared to Caucasian (CA) men. In addition to socioeconomic factors and lifestyle differences, molecular alterations contribute to this discrepancy. In this review, we summarize molecular genetics research results interrelated with the biology of PCa racial disparity. Androgen and androgen receptor (AR) pathways have long been associated with prostate growth. Racial differences have also been found among variants of the genes of the enzymes involved in androgen biosynthesis and metabolism, such as SRD5A2, CYP17, and CYP3A4. The levels of expression and CAG repeat length of AR also show racial divergence and may be critical molecular alterations for racial disparity. Growth factors and their receptors, which promote cancer cell growth, are another potential cause of the disparity; both EGFR and EPHB2, two of the most studied receptors, show interethnic differences. Differences have also been found among genes regulating cell apoptosis, such as BCL2, which is increased in PCa in the AA population. Recent developments in genetics, proteomics, and genomics, among other molecular biotechnologies, will greatly aid the advancement of translational research on PCa racial disparity, hopefully culminating in the discovery of novel mechanisms of disease, in addition to prognostic markers and novel therapeutic approaches.

High-grade prostatic intraepithelial neoplasia of the prostate: the precursor lesion of prostate cancer

High-grade intraepithelial neoplasia (HGPIN) is a lesion which is widely believed to be a precursor of prostatic adenocarcinoma. Correct morphologic identification of HGPIN and an understanding of how this diagnosis affects clinical management in the research setting are necessary as HGPIN is a premalignant lesion with many genetic alterations similar to prostate cancer, but is not yet invasive cancer. As such it is critical to differentiate between benign entities, HGPIN, and prostatic adenocarcinoma for experimental design and data interpretation. This review discusses HGPIN, clarifies the terminology used in pathology reports, and describes the clinical and research implications of this entity.

Mdm2-SNP309 polymorphism in prostate cancer: no evidence for association with increased risk or histopathological tumour characteristics

The search for inherited cancer susceptibility factors is a major focus of epidemiologic cancer studies. Analyses of single-nucleotide polymorphisms (SNP) in a variety of genes revealed a correlation between a specific allele variant and cancer predisposition. Human mouse double-minute 2 protein (Mdm2) is a cellular E3 ligase capable of ubiquitination and degradation of p53. Therefore, Mdm2 is a crucial factor of cell cycle control and cell survival. The Mdm2 promoter SNP309 was shown to increase Mdm2 expression and can, thereby, inhibit the p53 pathway. This SNP was found to be associated with increased risk and early onset of various malignancies. For prostate cancer no studies are reported to date. In a case-control study we determined the distribution of the Mdm2 SNP309 in 145 male subjects with prostate cancer and in 124 male controls without any malignancy using RFLP analysis. Cases and controls showed a similar distribution of the SNP (P=0.299). Genotype distribution showed neither an association with histopathological characteristics of the tumours nor with prognosis. Age at disease onset was also not modified by the SNP. This first study of the Mdm2 SNP309 in prostate cancer patients suggests no correlation between a certain allelic variant and an increased cancer risk.

Counting alleles in single lesions of prostate tumors from ethnically diverse patients

BACKGROUND

The presence of racial disparities in incidence and mortality rates are well-documented for prostate cancer. Nevertheless, it is unclear whether such disparities are due to genetic alterations that are involved in prostate cancer initiation. Here, we evaluated chromosome 8p allelic loss in a racially diverse cohort.

METHODS

Laser-capture microdissection was used to isolate tumors cells from individual lesions in 153 prostate cancer patients, and 8p allelic status was determined by "counting alleles." Statistical analyses examined the association between pathologic predictors and biochemical recurrence.

RESULTS AND CONCLUSIONS

Thirty percent of prostate lesions were missing an 8p allele at tumor initiation, while 51% of lesions lost an 8p allele during tumor progression. Biochemical recurrence after radical prostatectomy could be reliably predicted by surgical margin status only in lesions with extensive 8p allelic loss. There was, however, no racial disparity in 8p allelic loss at tumor initiation or during tumor progression, suggesting that the molecular event involved was similar between Caucasians and Africa Americans (CA and AA). Nonetheless, racial differences were present in values of prognostic factors for recurrence. Gleason score was the most important predictor of recurrence (HR=3.1, 95% CI=1.1, 9.2) in AA, while among CA, pathologic stage (HR=3.3, 95% CI=1.5, 7.6) and surgical margin (HR=4.7, 95% CI=1.8, 12.6) were the most important. Therefore, racial disparity in prostate cancer may be due to other factors that are involved in prostate cancer development.

FISH analysis of 107 prostate cancers shows that PTEN genomic deletion is associated with poor clinical outcome

This study examines the clinical impact of PTEN genomic deletions using fluorescence in situ hybridisation (FISH) analysis of 107 prostate cancers, with follow-up information covering a period of up to 10 years. Tissue microarray analysis using interphase FISH indicated that hemizygous PTEN losses were present in 42/107 (39%) of prostatic adenocarcinomas, with a homozygous PTEN deletion observed in 5/107 (5%) tumours. FISH analysis using closely linked probes centromeric and telomeric to the PTEN indicated that subband microdeletions accounted for ∼70% genomic losses. Kaplan–Meier survival analysis of PTEN genomic losses (hemizygous and homozygous deletion vs not deleted) identified subgroups with different prognosis based on their time to biochemical relapse after surgery, and demonstrated significant association between PTEN deletion and an earlier onset of disease recurrence (as determined by prostate-specific antigen levels). Homozygous PTEN deletion was associated with a much earlier onset of biochemical recurrence (P=0.002). Furthermore, PTEN loss at the time of prostatectomy correlated with clinical parameters of more advanced disease, such as extraprostatic extension and seminal vesicle invasion. Collectively, our data indicates that haploinsufficiency or PTEN genomic loss is an indicator of more advanced disease at surgery, and is predictive of a shorter time to biochemical recurrence of disease.

DNA copy number alterations in prostate cancers: a combined analysis of published CGH studies

BACKGROUND

Identifying genomic regions that are commonly deleted or gained in neoplastic cells is an important approach to identify tumor suppressor genes and oncogenes. Studies in the last two decades have identified a number of common DNA copy number alterations in prostate cancer. However, because of various sample sizes, diverse tumor types and sources, as well as a variety of detection methods with various sensitivities and resolutions, it is difficult to summarize and fully interpret the overall results.

METHODS

We performed a combined analysis of all published comparative genomic hybridization (CGH) studies of prostate cancer and estimated the frequency of alterations across the genome for all tumors, as well as in advanced and localized tumors separately. A total of 41 studies examining 872 cancers were included in this study.

RESULTS

The frequency of deletions and gains were estimated in all tumors, as well as in advanced and localized tumors. Eight deleted and five gained regions were found in more than 10% of the prostate tumors. An additional six regions were commonly deleted and seven were commonly gained in advanced tumors. While 8p was the most common location of deletion, occurring in about a third of all tumors and about half of advanced tumors, 8q was the most commonly gained region, affecting about a quarter of all tumors and about half of all advanced tumors.

CONCLUSIONS

The large number of tumors examined in this combined analysis provides better estimates of the frequency of specific alterations in the prostate cancer cell genome, and offers important clues for prioritizing efforts to identify tumor suppressor genes and oncogenes in these altered regions.

Adenoid Cystic/Basal Cell Carcinoma of the Prostate: Review and Update

Context.—Although most prostate carcinomas are of the conventional acinar type, unusual variants have been reported. Adenoid cystic/basal cell carcinoma of the prostate is a rare tumor with distinctive histopathologic features. There are only a few publications in the literature concerning the diagnosis, treatment, and prognosis of this neoplasm.

Objective.—To review current literature together with the clinical, pathologic, and immunohistochemical features of adenoid cystic/basal cell carcinoma of the prostate and offer a practical approach to the diagnosis—including the differential diagnosis—of this neoplasm in surgical pathologic specimens.

Data Sources.—Adenoid cystic/basal cell carcinoma of the prostate is composed of infiltrating basaloid cells forming dilated acinar and cribriform spaces with luminal basementlike material. Differentiation of adenoid cystic/basal cell carcinoma from basal cell hyperplasia and cribriform pattern of acinar adenocarcinoma may be difficult. The use of cytokeratin 34βE12 and prostate-specific antigen can help in difficult cases. Most cases are indolent, but metastasis has been documented in a few cases.

Conclusions.—Various histologic and immunohistochemical features are helpful in recognizing adenoid cystic/basal cell carcinoma of the prostate. This is a rare subtype of prostate cancer and correct diagnosis is important because of the unique clinical and biological features and the implications for treatment and prognosis.

Genomic profiling of hormone-naïve lymph node metastases in patients with prostate cancer

The progression of organ-confined prostate cancer to metastatic cancer is inevitably fatal. Consequently, identification of structural changes in the genome and associated transcriptional responses that drive this progression is critical to understanding the disease process and the development of biomarkers and therapeutic targets. In this study, whole genome copy number changes in genomes of hormone-naïve lymph node metastases were profiled using array comparative genomic hybridization, and matched primaries were included for a subset. Matched primaries and lymph node metastases showed very similar copy number profiles that are distinct from primary tumors that fail to metastasize.

Gain of chromosome X in prostatic atrophy detected by CGH and FISH analyses

BACKGROUND

Focal atrophy is presumed to be an indirect forerunner of prostate cancer. The aim of this study was to examine genetic alterations in prostate epithelia deriving from atrophic areas and compare these findings with those of cells deriving from paired prostate cancer in the same patient.

METHODS

Formalin fixed paraffin wax-embedded prostatectomy specimens from 20 prostate cancer patients were utilized in this study. Comparative Genomic Hybridization (CGH) was performed on atrophic areas. To validate the CGH results, Fluorescence in Situ Hybridization (FISH) analysis was performed on atrophic areas and paired cancer tissue.

RESULTS

Gain of the whole chromosome X was found as sole aberration in seven (70%) atrophic tissues by CGH. A gain of centromere X was observed in 13 (68.4%) atrophic areas and in 18 (90%) cancer tissues using FISH.

CONCLUSIONS

Our investigation reconfirms the genetical instability of cells of the atrophic acini and attention of relevance of gain of chromosome X in atrophic areas.

Expression analysis of imbalanced genes in prostate carcinoma using tissue microarrays

To identify candidate genes relevant for prostate tumour prognosis and progression, we performed an exhaustive gene search in seven previously described genomic-profiling studies of 161 prostate tumours, and four expression profiling studies of 61 tumours. From the resulting list of candidate genes, six were selected for protein-expression analysis based on the availability of antibodies applicable to paraffinised tissue: fatty acid synthase (FASN), MYC, β-adrenergic receptor kinase 1 (BARK1, GRK2) the catalytic subunits of protein phosphatases PP1α (PPP1CA) and PP2A (PPP2CB) and metastasis suppressor NM23-H1. These candidates were analysed by immunohistochemistry (IHC) on a tissue microarray containing 651 cores of primary prostate cancer samples and benign prostatic hyperplasias (BPH) from 175 patients. In univariate analysis, expression of PP1α (P=0.001) was found to strongly correlate with Gleason score. MYC immunostaining negatively correlated with both pT-stage and Gleason score (P<0.001 each) in univariate as well as in multivariate analysis. Furthermore, a subgroup of patients with high Gleason scores was characterised by a complete loss of BARK1 protein (P=0.023). In conclusion, our study revealed novel molecular markers of potential diagnostic and therapeutic relevance for prostate carcinoma.

Array CGH identifies distinct DNA copy number profiles of oncogenes and tumor suppressor genes in chromosomal- and microsatellite-unstable sporadic colorectal carcinomas

DNA copy number changes represent molecular fingerprints of solid tumors and are as such relevant for better understanding of tumor development and progression. In this study, we applied genome-wide array comparative genomic hybridization (aCGH) to identify gene-specific DNA copy number changes in chromosomal (CIN)- and microsatellite (MIN)-unstable sporadic colorectal cancers (sCRC). Genomic DNA was extracted from microdissected, matching normal colorectal epithelium and invasive tumor cells of formalin-fixed and paraffin-embedded tissues of 22 cases with colorectal cancer (CIN = 11, MIN = 11). DNA copy number changes were determined by aCGH for 287 target sequences in tumor cell DNAs, using pooled normal DNAs as reference. aCGH data of tumor cell DNAs was confirmed by fluorescence in situ hybridization (FISH) for three genes on serial tissues as those used for aCGH. aCGH revealed DNA copy number changes previously described by metaphase CGH (gains 7, 8q, 13q, and 20q; losses 8p, 15q, 18q, and 17p). However, chromosomal regions 20q, 13q, 7, and 17p were preferentially altered in CIN-type tumors and included DNA amplifications of eight genes on chromosome 20q (TOP1, AIB1, MYBL2, CAS, PTPN1, STK15, ZNF217, and CYP24), two genes on chromosome 13q (BRCA2 and D13S25), and three genes on chromosome 7 (IL6, CYLN2, and MET) as well as DNA deletions of two genes on chromosome 17p (HIC1 and LLGL1). Finally, additional CIN-tumor-associated DNA amplifications were identified for EXT1 (8q24.11) and MYC (8q24.12) as well as DNA deletions for MAP2K5 (15q23) and LAMA3 (18q11.2). In contrast, distinct MIN-tumor-associated DNA amplifications were detected for E2F5 (8p22-q21.3), GARP (11q13.5-q14), ATM (11q22.3), KAL (Xp22.3), and XIST (Xq13.2) as well as DNA deletions for RAF1 (3p25), DCC (18q21.3), and KEN (21q tel). aCGH revealed distinct DNA copy number changes of oncogenes and tumor suppressor genes in CIN- and MIN-type sporadic colorectal carcinomas. The identified candidate genes are likely to have distinct functional roles in the carcinogenesis and progression of CIN- and MIN-type sporadic CRCs and may be involved in the differential response of CIN- and MIN-type tumor cells to (adjuvant) therapy, such as 5-fluorouracil.

Interphase FISH analysis of PTEN in histologic sections shows genomic deletions in 68% of primary prostate cancer and 23% of high-grade prostatic intra-epithelial neoplasias

Prostate cancer (CaP) is characterized by the accumulation of both genetic and epigenetic alterations that transform premalignant lesions to invasive carcinoma. However, the molecular events underlying this critical transition are poorly understood. One of the important genes that might play a role in CaP development is the PTEN gene. At the present time, there has been no systematic analysis of the incidence of genomic PTEN deletion by fluorescence in situ hybridization (FISH) in CaP and associated preneoplastic histologic lesions. This study assesses the frequency of PTEN deletion by interphase FISH analysis in CaP and prostatic intra-epithelial neoplasia (PIN). Dual-color FISH was performed using DNA probes for bands 10q23.3 (PTEN locus) and chromosome 10 centromere using 35 radical prostatectomy specimens. PTEN deletions were not found in 3/3 of stroma, 6/6 samples of benign glandular epithelium, and 12/12 samples of low-grade PIN. However, PTEN deletions were found in 3/13 (23%) of high-grade PIN and 24/35 (68%) of CaP. Concordance was observed between PTEN deletion status and the overall cellular PTEN protein expression levels, as assessed by immunohistochemistry. The high frequency of PTEN deletion observed in CaP versus precursor lesions implicates a pivotal role for PTEN haploinsufficiency in the transition from preneoplastic PIN to CaP. Moreover, this observation is an important consideration for novel therapeutic trials in CaP in which biologic efficacy is influenced by the activity level of PTEN. These findings draw attention to the usefulness of this relatively simple FISH assay for future applications in clinical laboratories.

Genetic changes in localized prostate cancer of Japanese patients shown by comparative genomic hybridization

To search for additional amplification and deletion sites that may serve as a starting point for the discovery of new oncogenes or tumor suppressor genes, 30 Japanese localized prostate cancers were analyzed by comparative genomic hybridization (CGH) in this study. CGH was used to search for changes in DNA sequence copy-number in a series of 30 primary prostate adenocarcinomas, consisting of 22 cases of pT2N0 (organ confined; without capsular invasion) and 8 cases of pT3N0 (with capsular invasion), removed by radical prostatectomy. CGH revealed that the shortest regions of overlap (SRO) of gains in pT2N0 were at 8q22.2 approximately q24.2, 11q13.1 approximately q14.1, and 12q23 approximately q24.2, whereas the SRO of losses were seen at 8p23.3 approximately p22, 13q21.2 approximately p22, and 18q21 approximately q22. The SRO of gains in pT3N0 were noted at 5q32 approximately q34, 8q22.3 approximately q24.1, 11q14.1 approximately q22.3, and 12q22 approximately q24.2, whereas the SRO of losses were seen at 18q21.2 approximately q23. These results suggest that gains or losses of DNA in these regions are important for prostate cancer progression. The detection of the SRO may serve as a starting point to discover novel oncogenes and tumor suppressor genes involved in prostate cancer progression.

Molecular characterization of a consistent 4.5-megabase deletion at 4q28 in prostate cancer cells

Spectral karyotyping of prostate cell lines LNCaP, DU145, PC3, and 22RV demonstrated structural chromosome rearrangements involving the distal long arm of chromosome 4. In all but 22RV, these are nonreciprocal translocations between chromosomes 4 and 10. In 22RV, an apparently reciprocal t(2q;4q) is seen. Fluorescence in situ hybridization analysis of the chromosome 4 translocation breakpoints demonstrated that deletions were associated with all of the translocations, resulting in a net loss of chromosome material. Overlapping deletions in 4q28 approximately 34 were seen in LNCap, DU145, and 22RV, which defined an approximately 4.5-megabase pair common region of deletion. The deletion in PC3 was more proximal on 4q, involving the 4q21 approximately q26 region. A meta analysis of high-resolution definition of losses of chromosome material from published studies demonstrates that loss of 4q material may occur in at least 50% of primary tumors. This analysis defines a series of genes in the critical 4q region, which is potentially associated with prostate tumor development.

Simultaneous tumour-like, atypical basal cell hyperplasia and acinar adenocarcinoma of the prostate: a comparative morphological and genetic approach

Basal cell tumours of the prostatic gland are rare, and the classification is difficult. In the present case report, a large, tumour-like proliferation of atypical basaloid cells was found incidentally in a prostatectomy specimen that otherwise contained a conventional acinar adenocarcinoma. The basaloid cells displayed a solid or adenoid-cystic growth pattern and strongly expressed high-molecular-weight cytokeratins and bcl-2. A high Ki-67 index was recorded within the atypical basaloid cells, by far exceeding the one counted in the conventional adenocarcinoma. However, there were no definite criteria for a malignant behaviour of the basal cell tumour. Comparative genomic hybridisation from microdissected tumour cells yielded losses at the short arms of chromosomes 8 and 12 in the conventional adenocarcinoma and a normal karyotype in the basal cell tumour. The pathological findings favoured the diagnosis of an atypical basal cell hyperplasia.

Quantitation of conventional histologic parameters and biologic factors in prostatic needle biopsy are useful to distinguish paramalignant from malignant disease

The scope of this work was to determine the potential use of prostatic conventional histologic parameters and biologic factors in distinguishing between paramalignant and malignant prostatic disease, taking into account benign fragments of biopsies obtained from patients with prostatic cancer or from patients suspected to have cancer. Each prostate sample was semi-quantified for macronucleoli, mucin, crystalloid, collagen micronodules, and quantified for glands, stroma, AgNOR, and p53. The database covered 185 biopsy specimens from 136 patients: 56 samples from the same number of patients in whom all the biopsies were benign; 49 samples from patients whose biopsies showed malignant features, and 80 malignant samples. Discriminant analysis of the results showed statistical differences for four parameters: macronucleoli, mucin, gland volume, and AgNOR, allowing us to identify three patterns of prostate involvement: normal, paramalignant, and malignant. The discriminant function permitted an adequate classification of the three patterns in 84% of the cases. Normal areas showed glands with a mean volume of 38.93 microm3, inconspicuous nucleoli, low mucin production, and a mean AgNOR area of 1.26 microm2. Prostatic biopsies with prominent nucleoli and the presence of mucin (60%), gland volume of 22.31 microm3, and AgNOR area of 2.14 microm2 characterized the paramalignant condition. Malignant areas were characterized by mean glands with a volume of 8.11 microm3, prominent nucleoli, high mucin secretion (100%), and AgNOR area of 4.47 microm2. We concluded that modifications in prostate histoarquitecture and function, such as the presence of macronucleoli, volume of glands, abnormal secretion of acid mucin and AgNOR expression, represent important parameters that must be incorporated in the pathologist's evaluation of prostate biopsies to the purpose of indicating a subsequent biopsy, particulary in those patients with clinical suspicion of malignancy, and whose prostate biopsy specimen showed paramalignant areas.

Genetic pathways and new progression markers for prostate cancer suggested by microsatellite allelotyping

PURPOSE

At diagnosis, the biological behavior of prostate cancer is uncertain, making the choice of an adequate therapy option difficult. Performing microsatellite allelotyping on a large series of consecutive prostate cancers procured during radical prostatectomy at our institution, we sought to identify molecular markers associated with disease progression.

EXPERIMENTAL DESIGN

A total of 156 consecutive fresh tumor samples was prospectively collected and macroscopically dissected from the whole prostatectomy specimen immediately after operation. Histologically 100 samples contained >75% tumor cells and were therefore enrolled in the microsatellite allelotyping, using a total of 24 polymorphic markers for the chromosomal regions 5p, 5q, 7q, 8p, 9p, 9q, 13q, 17p, 17q, and 18q. Fresh paired normal and tumor DNA was investigated in fluorescent microsatellite analysis with automated laser product detection.

RESULTS

The incidence of tumor-DNA alterations [loss of heterozygosity or allelic imbalance (AI)] was highest for chromosomal regions 13q and 8p with 72 and 71%, respectively, followed by chromosomes 7q, 18q, 5q, and 17p with 57, 53, 41, and 39%, respectively. Alterations at chromosomes 8p, 9p, 13q, and 17p were significantly (P < 0.05) associated with advanced tumor stage, whereas AI at 8p and 17p was also associated with high Gleason score (P < 0.05). AI at 5q and 9p was associated with regional lymph node metastasis (P < 0.05). The combination of AI at 8p and 13q was strongly associated with advanced tumor stage (P < 0.0001).

CONCLUSIONS

With the obtained results, we are able to postulate three distinct pathways in prostate carcinogenesis, and we identified microsatellite markers of prognostic value.

Accuracy of an array comparative genomic hybridization (CGH) technique in detecting DNA copy number aberrations: comparison with conventional CGH and loss of heterozygosity analysis in prostate cancer

Although genomic DNA microarray (array comparative genomic hybridization [CGH]) technique is a rapid and powerful diagnostic tool for the comprehensive analysis of detailed chromosomal alterations of DNA copy numbers, its accuracy has not been well demonstrated. To clarify the accuracy of this technique, we applied array CGH spotted with 283 specific genes to 11 clinical prostate cancers, and the results were compared with comparative genomic hybridization (conventional CGH) and loss of heterozygosity (LOH) analysis using microsatellite DNA markers. The overall rate of correspondence between array CGH and conventional CGH with respect to the loss of DNA sequences was 94.5%. When the results of both CGH techniques were compared with those of LOH analysis, the correspondence rate of array CGH was significantly higher than that of conventional CGH (93.4% vs. 72.2%, P<0.05). In conclusion, the accuracy of array CGH was higher than that of conventional CGH in detecting losses of the DNA sequences. Array CGH is shown to be a promising tool for screening to identify unknown genes involved in tumorigenesis in prostate cancer.

Genetic aberrations in prostate carcinoma detected by comparative genomic hybridization and microsatellite analysis: association with progression and angiogenesis

BACKGROUND

In spite of increasing knowledge about the tumor biology of prostate cancer (PC), molecular events involved in tumor progression are not well characterized. There is evidence that a number of genetic alterations play a role in tumor progression and in addition, angiogenesis also contributes. In this study, comparative genomic hybridization (CGH), a sensitive method for detecting regional DNA copy number abnormalities, and microsatellite analysis was used to identify frequent genome changes in PC. Correlation of these data with microvessel density (MVD) and clinical follow-up data was performed to determine genetic alterations that are associated with angiogenesis and subsequent tumor progression.

METHODS

Fifty-seven paraffin embedded radical prostatectomy (RP) specimens were microdissected. DNA from the microdissected PC tissue was amplified by degenerate oligonucleoitide primed (DOP)-polymerase chain reaction (PCR), and CGH was performed on the PCR product. Quantitative analyses of the CGH profiles were performed using a t-statistic. Additionally, a microsatellite analysis of chromosome 13q was performed on a subgroup of 31 of the tumors. Using a polyclonal antibody against factor VIII, MVD was determined for all RP specimens. The results of CGH and microsatellite analysis were correlated with the clinical data of the patients and with MVD.

RESULTS

Forty-two of the tumors (75%) showed one or more gains while 39 (70%) showed one or more losses per tumor. The most frequent DNA copy number gains were on chromosome 3, 4, 7, 8, 10, 11, 12, 13, and X. The most frequent losses were on chromosomes 2, 5, 6, 8, 10, 13, 15, and 16. Cancer recurrence occurred in 15 patients. The total number of DNA copy number losses was significantly higher in patients with this progression (86%) than without (52%) (P < 0.001). There was no significant difference in the number of gains in patients with or without progression. Contingency table analysis showed a significant correlation between progression and losses in regions of chromosomes 6q and 13q and a gain of chromosome 7q. In multivariate analysis, only loss of chromosome 6 was independently prognostic. The gains that correlated most closely with MVD > 35 were on chromosomes 2q, 7q, and Xq, while the losses most closely associated with MVD > 35 were on chromosomes 8q, 10q, and 13q. However, only the association between loss of chromosome 13q and MVD > 35 was statistically significant. Microsatellite analysis revealed a statistically significant correlation between MVD and instability of locus 171.

CONCLUSIONS

This study indicates that the frequency of genetic alterations in PC as detected by CGH correlates with clinical outcome, and that losses of DNA from chromosomes 6q and 13q are important events that correlate with tumor progression, with loss of 13q, especially instability of locus 171, also associated with angiogenesis.

Molecular markers to identify patients at risk for recurrence after primary treatment for prostate cancer

Accurate prognostication is a prerequisite for accurate therapeutics and management of prostate cancer because indolent tumors may require no intervention, whereas aggressive tumors lead to patient mortality. There is a critical need to define these subgroups of patients with prostate cancer differing in clinical outcome. Prognostic nomograms based on clinical data provide useful predictions of clinical states and outcomes, but they need further refinements to improve accuracy and universality. Genomic and proteomic analyses have provided many novel markers that may help define prognostic parameters based on the underlying biology of prostate cancer progression at the molecular level. These molecular markers are likely to augment traditional prognostic modalities by providing a set of molecularly defined and quantifiable variables. Encompassing the genome, transcriptome, and proteome of prostate cancer will likely provide "molecular signatures" that will bridge prognostication, prediction, and treatment in a single continuum.

Spectral karyotype (SKY) analysis of human prostate carcinoma cell lines

BACKGROUND

Well-characterized in vitro model systems provide an invaluable tool for studying prostate cancer in the laboratory. Detailed karyotypes have been reported using modern techniques such as multiplex fluorescence in situ hybridization (M-FISH) and spectral karyotyping (SKY) for LNCaP, DU 145, NCI-H660, and PC-3 cell lines. However, karyotypic data for more recently established prostate carcinoma cell lines are still limited.

METHODS

Classical (G-banding) and SKY analyses were performed on ten prostate carcinoma cell lines: 22Rv1, CWR-R1, DuCaP, LAPC-4, MDA PCa 1, MDA PCa 2a, MDA PCa 2b, PC-346C, PSK-1, and VCaP.

RESULTS

Chromosomal abnormalities were identified in all cell lines, although the number and complexity varied greatly among them. PC-346C, established from a primary tumor, exhibited the lowest number (3) of clonal structural abnormalities, while DuCaP, established from a metastasis from a hormone-refractory patient, exhibited both the highest number (31) and largest complexity of structural abnormalities. In various subsets of these models, breakpoints were identified in chromosomal regions previously described as being involved in prostate cancer (e.g., 8p, 10q, 13q, and 16q).

CONCLUSIONS

The present study provides a comprehensive karyotypic analysis of a large number of prostate carcinoma cell lines, and offers a valuable resource for future investigations.

Molecular Techniques and Prostate Cancer Diagnostic

Recent advances in molecular techniques have given the opportunity to assess genomic and proteomic alterations comprehensively and rapidly in routinely acquired tissue samples. In particular, new markers derived from qualitative and quantitative DNA, RNA, and protein analysis have provided additional objective information to supplant and extend the morphologic interpretations and have been increasingly integrated into the final surgical pathology diagnosis. In this review several recently developed molecular techniques are described and illustrated. The focus is on prostate cancer diagnostics, as an example of their application.

Prostate cancer biomarkers: a current perspective

Genomic- and proteomic-based studies have led to the identification of a large number of candidate biomarkers, as well as signature patterns of multiple markers for prostate cancer diagnosis, disease progression and prediction of survival. While these candidates include the usual suspects, including oncogenes, proliferation markers and cytoskeletal proteins, there are many additional unexpected molecules such as those involved in processes such as transcriptional repression and fatty acid metabolism. Patterns of expression serving as useful biomarkers is a new and, as yet, clinically untested concept which promises to permit a consideration of the complex milieu of cancer. Exciting as these developments are, clinical application will have to await careful validation of these candidates by independent biochemical approaches over large and diverse samples.

High-resolution genomic profiling of occult micrometastatic tumor cells

Metastasis is responsible for most deaths from cancer. Currently, little is known about the early genetic events in the metastatic evolution. Here we describe the application of a newly developed strategy for an in-depth characterization of genomic changes in micrometastatic cells. Unique tumor cell lines were established from bone marrow of patients with cancer of the prostate and analyzed by multiplex-FISH (M-FISH) and array CGH. M-FISH revealed that the occult disseminated cells were characterized by very complex numerical and structural aberrations. Many of these aberrations resulted in chromosomal gains and losses, such as losses of 8p, 13q, and 18q and gains of 8q, 9q, 20, and the X chromosome, which are typically observed in prostate cancer. Array CGH allowed an unprecedented high-resolution assessment of copy number changes, pinpointing commonly gained or lost regions, which should narrow down the identification of regions critically involved in metastasis. Thus, occult micrometastatic cells are now amenable to detailed analyses of their genome. Markers for prognosis and treatment decisions can now be established.

Current status of the molecular genetics of human prostatic adenocarcinomas

Molecular genetic mechanisms involved in the progression of prostate cancer are not well understood due to extensive tumor heterogeneity and lack of suitable models. New methods such as fluorescence in-situ hybridization (FISH), comparative genomic hybridization (CGH) and microsatellite analysis have documented losses or gains on various chromosomes. Altered chromosomal regions have been associated with the activation of oncogenes and the inactivation of tumor suppressor genes or defects in mismatch repair (MMR) genes. It is suggested that increased genomic instability is associated with decreased androgen-responsive and progressive behavior of human prostate tumors, but it remains unclear whether this genomic instability is causing the progression of cancer or is the consequence of cancer. Extended studies on hereditary prostate cancer have identified 7 prostate cancer susceptibility loci on several chromosomes, but no specific gene has been confined for a large proportion of susceptibility. In this review we summarize the ongoing molecular genetic events associated with the sporadic and hereditary prostate cancer development and progression.

TMEFF2 is an androgen-regulated gene exhibiting antiproliferative effects in prostate cancer cells

We have identified a gene that is highly expressed in the androgen-dependent prostate cancer cell line, LNCaP. Sequence analysis revealed that it was identical to a recently cloned gene designated TMEFF2, which encodes a transmembrane protein containing an epidermal growth factor (EGF)-like motif and two follistatin domains. This gene was highly expressed only in primary samples of normal prostate and prostate cancer as well as normal brain. Expression of the gene was controlled by androgen as shown by dihydrotestosterone markedly increasing TMEFF2 expression in LNCaP cells. Also, androgen-dependent human prostate cancer xenografts (CWR22) expressed high levels of TMEFF2 and these levels markedly decreased by day 10 after castration of the mice. Furthermore, a large number of androgen-dependent xenografts (CWR22, LuCaP-35, LAPC-4AD, LAPC-9AD) exhibited higher levels of TMEFF2 mRNA than androgen-independent xenografts (CWR22R, LAPC-3AI, LAPC-4AI, LAPC-9AI). Ectopic expression of TMEFF2 in DU145 and PC3 cells resulted in their prominent inhibition of growth. Taken together, the results demonstrate that TMEFF2 is a androgen-regulated gene, which can suppress growth of prostate cancer cells and our xenograft data show that escape of prostate cancer cells from androgen modulation causes them to decrease their expression of this gene, which may result in their more malignant behavior.

Defining the region(s) of deletion at 6q16-q22 in human prostate cancer

Deletion of the long arm of chromosome 6 (6q) frequently occurs in many neoplasms, including carcinomas of the prostate and breast and melanoma, suggesting the location of a tumor-suppressor gene or genes at 6q. At present, however, the region of deletion has not been well defined, and the target gene of deletion remains to be identified. In this study, we analyzed 44 primary prostate cancers with 16 polymorphic markers for loss of heterozygosity (LOH) by using PCR-based techniques. We also examined 23 cell lines/xenografts of prostate cancer with 38 markers for LOH by the method of homozygosity mapping of deletion. LOH at 6q16 - q22 was detected in 21 of 44 (48%) primary tumors and in 12 of 23 (52%) cell lines/xenografts. Two regions of LOH were defined. One was 7.5 cM at 6q16 - q21 between markers D6S1716 and D6S1580, and the other was 4.3 cM at 6q22 between D6S261 and D6S1702. Whereas no correlation was found between LOH at 6q16-q22 and patient age at diagnosis or Gleason score, tumors at higher stage appear to have more frequent LOH. These findings suggest that deletion of 6q16 - q22 is a frequent event in prostate cancer, and that the deletion originates from two distinct regions. These results should be useful in identifying the target gene(s) of deletion at 6q.

Compilation of published comparative genomic hybridization studies

The power of comparative genomic hybridization (CGH) has been clearly proven since the first paper appeared in 1992 as a tool to characterize chromosomal imbalances in neoplasias. This review summarizes the chromosomal imbalances detected by CGH in solid tumors and in hemopathies. In May of 2001, we took a census of 430 articles providing information on 11,984 cases of human solid tumors or hematologic malignancies. Comparative generic hybridization has detected a number of recurrent regions of amplification or deletion that allows for identification of new chromosomal loci (oncogenes, tumor suppressor genes, or other genes) involved in the development, progression, and clonal evolution of tumors. When CGH data from different studies are combined, a pattern of nonrandom genetic aberrations appears. As expected, some of these gains and losses are common to different types of pathologies, while others are more tumor-specific.

Identification of a gene frequently mutated in prostate tumors

Although prostate cancer is the second leading cause of cancer death for men in the United States, the genetics of tumor development are poorly understood. Several expressed sequence tagged genes (ESTs) that are expressed predominantly in the prostate have recently been identified, although their role in the development and maintenance of the prostate is unknown. Here, we demonstrate that the gene identified as UNIGENE cluster Hs. 104215, which codes for a message found predominantly in the prostate, may be important in tumor development. We name this gene PCan1 for Prostate Cancer gene 1. Northern blot experiments were performed using RNA isolated from tumor-derived cell lines and human prostate to determine the expression pattern of the gene. DNA sequencing was used to identify mutations that occurred in tumor tissue. By Northern blot analysis, this gene product was not detectable in LNCaP, DU 145, or PC-3 prostate cancer cell lines, although it was readily observed in RNA isolated from total prostate and from dissected central and peripheral regions of prostate. Sequence analysis of genomic DNA from LNCaP, DU 145, or PC-3 cells demonstrated a G/A polymorphism at position 193. Analysis of matched tumor-derived DNA and blood-derived DNA samples from 11 of 13 patients who had undergone a radical prostatectomy and who were homozygous for A in blood-derived DNA demonstrated mutation of position 193 in matched tumor samples resulting in G/A polymorphism. Sixteen additional patient samples were G/A polymorphic in both blood-derived DNA and tumor-derived DNA and two samples were GG in both blood-derived and tumor-derived DNA. Our results suggest that this gene may be a hot spot for mutation in prostate cancer, especially because our radiation hybrid mapping located this gene within a region identified in linkage mapping studies of affected families with prostate cancer. Loss of heterozygosity in prostate tumors has also been reported at the location of PCan1. Further studies to determine the functional role of this candidate tumor suppressor gene are warranted.

Genetic changes in stage pT2N0 prostate cancer studied by comparative genomic hybridization

OBJECTIVE

To identify chromosomal regions important for progression in clinically organ-confined prostate cancer, as the genetic changes underlying the development and progression of prostate cancer are poorly understood.

MATERIALS AND METHODS

Comparative genomic hybridization (CGH) was used to search for DNA sequence copy-number changes in a series of 50 primary organ-confined prostate adenocarcinomas (pT2N0) removed by radical prostatectomy.

RESULTS

CGH analysis indicated that 23 (46%) of the primary prostate adenocarcinomas showed chromosome alterations. The percentage of tumours with losses (38%) was higher than with gains (28%). Losses of 13q (24%), 8p (18%), 6q (10%), 16q (8%), 18q (6%) and 5q (6%) and gains of 17q (12%), 20q (12%), 9q (10%), 17p (8%) and 8q (6%) were the most frequent alterations. Amplifications were found at 8q24-qter. Minimal overlapping regions of loss, indicative of the presence of tumour-suppressor genes, were mapped to 13q21.1-q21.3 and 8p21.2, and minimal overlapping regions of gain, indicative of the presence of oncogenes, were found at 9q34.4-qter, 17q25-qter and 20q13.3-qter. There was a significant association between Gleason score and losses and gains (P = 0.003), and an association between chromosomal imbalance and high histological grade (P = 0.008).

CONCLUSION

These results suggest that losses or gains of DNA in these regions are important for prostate cancer progression, and document the spectrum of chromosomal alterations in stage pT2N0 of clinically organ-confined prostate cancer.

Automated screening for genomic imbalances using matrix-based comparative genomic hybridization

Genome-wide screening for chromosomal imbalances using comparative genomic hybridization (CGH) revealed a wealth of data on previously unrecognized tumor-specific genomic alterations. CGH to microarrays of DNA, an approach termed matrix-CGH, allows detection of genomic imbalances at a much higher resolution. We show that matrix CGH is also feasible from small tissue samples requiring universal amplification of genomic DNA. Because widespread application of matrix-CGH experiments using large numbers of DNA targets demands a high degree of automation, we have developed a protocol for a fully automated procedure. The use of specialized instrumentation for the generation of DNA chips, their hybridization, scanning, and evaluation required numerous alterations and modifications of the initial protocol. We here present the elaboration and testing of automated matrix-CGH. A chip consisting of 188 different genomic DNA fragments, cloned in bacterial artificial chromosome (BAC) or P1-derived artificial chromosome (PAC) vectors and immobilized in replicas of 10, was used to assess the performance of the automated protocol in determining the gene dosage variations in tumor cell lines COLO320-HSR, HL60, and NGP. Although ratios of matrix-CGH were highly concordant with results of chromosomal CGH (85%), the dynamic range of the matrix-CGH ratios was highly superior. Investigation of the two amplicons on 8q24 in COLO320-HSR and HL60, containing the MYC gene, revealed a homogeneous amplicon in COLO320-HSR but a heterogeneous amplification pattern in HL60 cells. Although control clones for normalization of the signal ratios can be predicted in cases with defined chromosomal aberrations, in primary tumors such data are often not available, requiring alternative normalization algorithms. Testing such algorithms in a primary high-grade B-cell lymphoma, we show the feasibility of this approach. With the matrix-CGH protocol presented here, robust and reliable detection of genomic gains and losses is accomplished in an automated fashion, which provides the basis for widespread application in tumor and clinical genetics.

Activins and inhibins in endocrine and other tumors

Inhibin and activin are members of the TGF beta superfamily of growth and differentiation factors. They were first identified as gonadal-derived regulators of pituitary FSH and were subsequently assigned multiple actions in a wide range of tissues. More recently, the inhibin alpha subunit was considered as a tumor suppressor based on functional studies employing transgenic mouse models. This review evaluates the functional and molecular evidence that the inhibin alpha subunit is a tumor suppressor in endocrine cancers. The evaluation highlights the discrepant results from the human and mouse studies, as well as the differences between endocrine tumor types. In addition, we examine the evidence that the activin-signaling pathway is tumor suppressive and identify organ-specific differences in the actions and putative roles of this pathway in endocrine tumors. In summary, there is a considerable body of evidence to support the role of inhibins and activins in endocrine-related tumors. Future studies will define the mechanisms by which inhibins and activins contribute to the process of initiation, promotion, or progression of endocrine-related cancers.

Relationship between ABO blood groups and carcinoma of esophagus and cardia in Chaoshan inhabitants of China

AIM

To study the relationship between ABO blood groups and carcinoma of esophagus and cardia in Chaoshan inhabitants of China, which is a unique Littoral high-risk area of esophageal carcinoma in China. The poor communication and transportation in the past has made Chaoshan a relatively closed area and kept its culture and custure of old China thousand years ago.

METHODS

Data on age, sex, ABO blood type and X-ray or pathological diagnose of the patients with carcinoma of esophagus or cardia were collected from the Tumor Hospital. First Affiliated Hospital, Second Affiliated Hospital of Shantou University Medical College; and the Central Hospital of Shantou and the Central Hospital of Jieyang. A total of 6685 patients with esophageal carcinoma (EC) and 2955 patients with cardiac cancer (CC) in Chaoshan district were retrospectively assessed for their association with ABO blood groups.

RESULTS

The distribution of ABO blood groups in patients with EC or CC was similar to the normal local population in Chaoshan. However, blood group B in male patients with CC and in the patients with carcinoma in the upper third esophagus was 2.3% and 4.7% higher than the corresponding controls. The relative risk B O was 1.1415 (P<0.05) and 1.2696 (P<0.05), respectively. No relationship was found between ABO blood groups and tumor differentiation.

CONCLUSION

ABO blood group B is associated with the incidence of CC in male individuals and carcinoma in the upper third esophagus. The distribution of ABO blood groups varies in the different geographical and ethnic groups. As a result, proper controls are very important for such studies.