Genetic instability in superficial bladder cancer and adjacent mucosa: an interphase cytogenetic study

Bladder cancer extracellular vesicles drive tumorigenesis by inducing the unfolded protein response in endoplasmic reticulum of nonmalignant cells

The field cancerization effect has been proposed to explain bladder cancer's multifocal and recurrent nature, yet the mechanisms of this effect remain unknown. In this work, using cell biology, flow cytometry, and qPCR analyses, along with a xenograft mouse tumor model, we show that chronic exposure to tumor-derived extracellular vesicles (TEVs) results in the neoplastic transformation of nonmalignant human SV-HUC urothelial cells. Inhibition of EV uptake prevented this transformation. Transformed cells not only possessed several oncogenic properties, such as increased genome instability, loss of cell-cell contact inhibition, and invasiveness, but also displayed altered morphology and cell structures, such as an enlarged cytoplasm with disrupted endoplasmic reticulum (ER) alignment and the accumulation of smaller mitochondria. Exposure of SV-HUC cells to TEVs provoked the unfolded protein response in the endoplasmic reticulum (UPR^ER). Prolonged induction of UPR^ER signaling activated the survival branch of the UPR^ER pathway, in which cells had elevated expression of inositol-requiring enzyme 1 (IRE1), NF-κB, and the inflammatory cytokine leptin, and incurred loss of the pro-apoptotic protein C/EBP homologous protein (CHOP). More importantly, inhibition of ER stress by docosahexaenoic acid prevented TEV-induced transformation. We propose that TEVs promote malignant transformation of predisposed cells by inhibiting pro-apoptotic signals and activating tumor-promoting ER stress-induced unfolded protein response and inflammation. This study provides detailed insight into the mechanisms underlying the bladder cancer field effect and tumor recurrence.

Paired Exome Analysis Reveals Clonal Evolution and Potential Therapeutic Targets in Urothelial Carcinoma

Greater knowledge concerning tumor heterogeneity and clonality is needed to determine the impact of targeted treatment in the setting of bladder cancer. In this study, we performed whole-exome, transcriptome, and deep-focused sequencing of metachronous tumors from 29 patients initially diagnosed with early-stage bladder tumors (14 with nonprogressive disease and 15 with progressive disease). Tumors from patients with progressive disease showed a higher variance of the intrapatient mutational spectrum and a higher frequency of APOBEC-related mutations. Allele-specific expression was also higher in these patients, particularly in tumor suppressor genes. Phylogenetic analysis revealed a common origin of the metachronous tumors, with a higher proportion of clonal mutations in the ancestral branch; however, 19 potential therapeutic targets were identified as both ancestral and tumor-specific alterations. Few subclones were present based on PyClone analysis. Our results illuminate tumor evolution and identify candidate therapeutic targets in bladder cancer. Cancer Res; 76(19); 5894-906. ©2016 AACR.

Localization of P2X receptor subtypes 2, 3 and 7 in human urinary bladder

BACKGROUND

Voiding dysfunctions are a common problem that has a severe negative impact on the quality of life. Today there is a need for new drug targets for these conditions. The role of ATP receptors in bladder physiology has been studied for some time, primarily in animal models. The aim of this work is to investigate the localization of the ATP receptors P2X2, P2X3 and P2X7 and their colocalization with vimentin and actin in the human urinary bladder.

METHODS

Immunohistochemical analysis was conducted on full-thickness bladder tissues from fundus and trigonum collected from 15 patients undergoing open radical cystectomy due to chronic cystitis, bladder cancer or locally advanced prostate cancer. Colocalization analyses were performed between the three different P2X subtypes and the structural proteins vimentin and actin. Specimens were examined using epifluorescence microscopy and correlation coefficients were calculated for each costaining as well as the mean distance from the laminin positive basal side of the urothelium to the vimentin positive cells located in the suburothelium.

RESULTS

P2X2 was expressed in vimentin positive cells located in the suburothelium. Less distinct labelling of P2X2 was also observed in actin positive smooth muscle cells and in the urothelium. P2X3 was expressed in vimentin positive cells surrounding the smooth muscle, and in vimentin positive cells located in the suburothelium. Weaker P2X3 labelling was seen in the urothelium. P2X7 was expressed in the smooth muscle cells and the urothelium. In the suburothelium, cells double positive for P2X2 and vimentin where located closer to the urothelium while cells double positive for P2X3 and vimentin where located further from the urothelium.

CONCLUSION

The results from this study demonstrate that there is a significant difference in the expression of the purinergic P2X2, P2X3 and P2X7 receptors in the different histological layers of the human urinary bladder.

Genetic alterations of chromosomes, p53 and p16 genes in low- and high-grade bladder cancer

A majority of patients with bladder cancer present with superficial disease and subsequently, some patients show progression to muscle invasive or metastatic disease. Bladder cancer has a complex genetic process and identification of the genetic alterations which occur during progression may lead to the understanding of the nature of the disease and provide the possibility of early treatment. The aim of the present study was to compare the structural and numerical chromosomal differences and changes in the p16 and p53 genes between low-grade (LG) and high-grade (HG) bladder cancer (BC) using cytogenetic and molecular cytogenetic methods. Between March 2009 and March 2010, cytogenetic analyses were carried out on tumor and blood samples in 34 patients with transitional cell type BC, and on blood samples of 34 healthy patients as a control group. Fluorescence in situ hybridization probes for the p16 and p53 genes were also used to screen the alterations in these genes in 32 patients with BC. The patients were divided into two groups (LG and HG) and the findings were compared. A total of 11 (32.3%) patients exhibited LGBC, 22 (64.7%) exhibited HGBC and one (3%) patient exhibited carcinoma in situ. There were no differences between the LGBC and HGBC groups according to the number of chromosomal aberrations (P=0.714); however, differences between alterations of the p16 and p53 genes were significant (P=0.002 and P=0.039). Almost all structural abnormalities were found to be located to the 1q21, 1q32, 3p21 and 5q31 regions in patients with HG tumors. In conclusion, the p16 and p53 genes were altered more prominently in patients with HG tumors compared with LG tumors. The structural abnormalities in the 1q21, 1q32, 3p21 and 5q31 regions were observed more frequently in patients with HG tumors. These regions may play significant roles in the progression of BC, but further studies are required to find candidate genes for a panel of BC.

Urinary protein biomarker panel for the detection of recurrent bladder cancer

BACKGROUND

Up to 70% of patients with non-muscle-invasive bladder cancer (NMIBC) experience disease recurrence, making it one of the most prevalent cancers in the United States. The purpose of this study was to test the performance of a multiplex urinary biomarker assay for the monitoring of voided urine for recurrent bladder cancer.

METHODS

This retrospective, multicenter study included a total of 125 subjects with a history of bladder cancer. Voided urine specimens were collected before procedure from these subjects (53 with confirmed tumor recurrence and 72 with confirmed non-tumor recurrence) for analysis. A prediction rule generated from the performance characteristics of 10 single biomarkers (IL8, MMP9, MMP10, SERPINA1, VEGFA, ANG, CA9, APOE, SERPINE1, and SDC1) was measured using ELISA. The diagnostic performance of the biomarker panel was assessed using receiver operator curves (ROC) and descriptive statistical values (e.g., sensitivity and specificity).

RESULTS

The combination of all 10 biomarkers outperformed any single biomarker with a calculated AUROC for the diagnostic panel of 0.904 [95% confidence interval (CI), 0.853-0.956]. The multiplex assay achieved an overall sensitivity of 79% and specificity of 88% for recurrent bladder cancer and significantly outperformed the Urovysion cytogenetic assay (sensitivity 42%, specificity 94%) and voided urinary cytology (sensitivity 33%, specificity 90%).

CONCLUSIONS

A diagnostic panel of 10 urinary biomarkers that accurately detects primary bladder cancer also performs well for the detection of recurrent bladder cancer.

IMPACT

The identification of a reliable urine-based surveillance and detection assay would be of benefit to both patients and the healthcare system.

The bladder cancer genome; chromosomal changes as prognostic makers, opportunities, and obstacles

During the past decades, the complexity of the bladder cancer genome has become evident. Early cytogenetic studies identified several patterns of chromosomal changes, particularly the frequent loss of chromosome 9. The cytogenetic approach was replaced by molecular methods, such as comparative genome hybridization (CGH) and loss of heterozygosity (LOH) analyses that describe genomic changes at a molecular and higher resolution. With these methods, the full complexity of the bladder cancer genome has been better appreciated. Using CGH and LOH analyses, it also became apparent that premalignant lesions of the bladder, such as hyperplasia and dysplasia, as well as carcinoma in situ (CIS), showed genomic changes. Whole genome analyses showed that low stage, low grade tumors generally show fewer changes than tumors of higher stage and grade. In addition, several genomic alterations were shown to be highly specific for more aggressive and invasive tumors. Based on the general association between complex genomic changes and tumor behavior, several investigations have been directed towards the identification of prognostic genomic markers for urothelial cancer. A complicating factor in the analysis and understanding of bladder cancer genomic progression is that recurring and, hence, chronologically later tumors may show genomes less rearranged than preceding tumors. Furthermore, morphologically normal urothelium in patients with bladder cancer frequently show the same type of genomic alterations as the tumor proper. This makes an issue of to what extent information on genomic changes will produce reliable prognostic information when limited to the tumor proper.

CEUS in the differentiation between low and high-grade bladder carcinoma

INTRODUCTION

Bladder cancer ranks 4th overall in the number of newly diagnosed cancers and 10th in causes of cancer deaths. More than 90% of all cases of bladder cancer are transitional cell carcinoma (TCC). The goal of this study is to confirm the usefulness of low mechanical index contrast-enhanced ultrasonography (CEUS), also in association with time-intensity curves, in the differentiation between high- and low-grade bladder malignant lesions.

MATERIALS AND METHODS

From February 2006 to February 2012 we recruited 144 patients. All patients underwent grayscale ultrasonography (US), color-Doppler ultrasonography (CDUS) and contrast-enhanced ultrasonography (CEUS). Subsequently all patients underwent cystoscopy and TURB.

RESULTS

HISTOLOGICAL DIAGNOSES WERE: 88 high-grade carcinomas (61.1%), and 56 low-grade carcinomas (38.9%). Sensitivity and specificity of CDUS were 87.5% (126/144) and 60%, respectively. Sensitivity and specificity of CEUS were 90.9% and 85.7%, respectively. Sensitivity and specificity of TIC were 91.6% (132/144) and 85.7%, respectively.

DISCUSSION AND CONCLUSIONS

CEUS is a reliable noninvasive method for differentiating low- and high-grade bladder carcinomas since it provides typical enhancement patterns as well as specific contrast-sonographic perfusion curves.

Bladder cancer: translating molecular genetic insights into clinical practice

Transitional cell (urothelial) carcinoma of the bladder is the second most common urologic malignancy and is one of the best understood neoplasms, with relatively well-defined pathogenetic pathways, natural history, and tumor biology. Conventional clinical and pathologic parameters are widely used to grade and stage tumors and to predict clinical outcome of transitional cell carcinoma; but the predictive ability of these parameters is limited, and there is a lack of indices that could allow prospective assessment of risk for individual patients. In the last decade, a wide range of candidate biomarkers representing key pathways in carcinogenesis have been reported to be clinically relevant and potentially useful as diagnostic and prognostic molecular markers, and as potential therapeutic targets. The use of molecular markers has facilitated the development of novel and more accurate diagnostic, prognostic, and therapeutic strategies. FGFR3 and TP53 mutations have been recognized as key genetic pathways in the carcinogenesis of transitional cell carcinoma. FGFR3 appears to be the most frequently mutated oncogene in transitional cell carcinoma; its mutation is strongly associated with low tumor grade, early stage, and low recurrence rate, which confer a better overall prognosis. In contrast, TP53 mutations are associated with higher tumor grade, more advanced stage, and more frequent tumor recurrences. These molecular markers offer the potential to characterize individual urothelial neoplasms more completely than is possible by histologic evaluation alone. Areas in which molecular markers may prove valuable include prediction of tumor recurrence, molecular staging of transitional cell carcinoma, detection of lymph node metastasis and circulating cancer cells, identification of therapeutic targets, and prediction of response to therapy. With accumulating molecular knowledge of transitional cell carcinoma, we are closer to the goal of bridging the gap between molecular findings and clinical outcomes. Assessment of key genetic pathways and expression profiles could ultimately establish a set of molecular markers to predict the biological nature of tumors and to establish new standards for molecular tumor grading, classification, and prognostication. The main focus of this review is to discuss clinically relevant biomarkers that might be useful in the management of transitional cell carcinoma and to provide approaches in the analysis of molecular pathways that influence the clinical course of bladder cancer.

DNA methylation patterns in bladder cancer and washing cell sediments: a perspective for tumor recurrence detection

Background

Epigenetic alterations are a hallmark of human cancer. In this study, we aimed to investigate whether aberrant DNA methylation of cancer-associated genes is related to urinary bladder cancer recurrence.

Methods

A set of 4 genes, including CDH1 (E-cadherin), SFN (stratifin), RARB (retinoic acid receptor, beta) and RASSF1A (Ras association (RalGDS/AF-6) domain family 1), had their methylation patterns evaluated by MSP (Methylation-Specific Polymerase Chain Reaction) analysis in 49 fresh urinary bladder carcinoma tissues (including 14 cases paired with adjacent normal bladder epithelium, 3 squamous cell carcinomas and 2 adenocarcinomas) and 24 cell sediment samples from bladder washings of patients classified as cancer-free by cytological analysis (control group). A third set of samples included 39 archived tumor fragments and 23 matched washouts from 20 urinary bladder cancer patients in post-surgical monitoring. After genomic DNA isolation and sodium bisulfite modification, methylation patterns were determined and correlated with standard clinic-histopathological parameters.

Results

CDH1 and SFN genes were methylated at high frequencies in bladder cancer as well as in paired normal adjacent tissue and exfoliated cells from cancer-free patients. Although no statistically significant differences were found between RARB and RASSF1A methylation and the clinical and histopathological parameters in bladder cancer, a sensitivity of 95% and a specificity of 71% were observed for RARB methylation (Fisher's Exact test (p < 0.0001; OR = 48.89) and, 58% and 17% (p < 0.05; OR = 0.29) for RASSF1A gene, respectively, in relation to the control group.

Conclusion

Indistinct DNA hypermethylation of CDH1 and SFN genes between tumoral and normal urinary bladder samples suggests that these epigenetic features are not suitable biomarkers for urinary bladder cancer. However, RARB and RASSF1A gene methylation appears to be an initial event in urinary bladder carcinogenesis and should be considered as defining a panel of differentially methylated genes in this neoplasia in order to maximize the diagnostic coverage of epigenetic markers, especially in studies aiming at early recurrence detection.

Familial papillary renal carcinoma: cytogenetic characterization in normal and tumor tissues in two brothers. A case report

BACKGROUND

Renal tumor subtypes are associated with distinct, recurring cytogenetic abnormalities and hereditary cancer syndromes. In papillary renal carcinoma, trisomy 7 and 17 and loss of the Y chromosome are the most common chromosomal defects.

CASE PRESENTATION

The present paper analyzes the chromosomes 7, 17, and Y alterations found in familial papillary carcinoma and in the normal tissue of two brothers. The evaluation, performed by fluorescence in situ hybridization (FISH) and cytogenetic conventional methods, was carried out on blood samples, normal kidney tissue, and tumor samples of the two brothers. Patient 1 showed gains of chromosomes 7 and 17 both in normal and tumor tissue. Chromosome Y status was normal. Patient 2 showed chromosome 7 and 17 gains, chromosome Y loss in tumor and chromosome 17 and Y alterations in normal kidney tissue. The constitutional karyotype was normal in both brothers.

CONCLUSIONS

Of particular relevance were the chromosome aberrations found in normal kidney parenchyma. In fact, the progressive alterations of 7, 17, and Y chromosomes could provide evidence of early genetic instability of tissue and may even precede the development of macroscopically identifiable lesions.

On the origin of syn- and metachronous urothelial carcinomas

OBJECTIVE

To evaluate existing models for the origin of meta- and synchronous urothelial carcinomas in light of the accumulated genetic data.

METHODS

Published studies on the clonal origin and genetic relationships of syn- and metachronous tumors, genetic aberrations in normal and premalignant urothelial lesions, as well as histologic and genetic mapping studies of cystectomized bladder samples are reviewed.

RESULTS

The most common models for the origin of syn- and metachronous tumors are found to conform less well to the accumulated genetic data. A new model is proposed, the field-first-tumor-later model, in which aberrant cells with a stem cell, or stem cell-like, origin spread in the urothelium by cellular displacement, creating fields of premalignant cells. Tumor growth is suggested to be initiated by critical genetic events occurring in individual cells in such fields. Hence, recurring tumors are proposed to originate from a shared field of premalignant cells and not from previous overt tumors.

CONCLUSIONS

The proposed model can better account for the existing genetic and histological data on syn- and metachronous urothelial carcinomas.

Epithelial-Restricted Gene Profile of Primary Cultures from Human Prostate Tumors: A Molecular Approach to Predict Clinical Behavior of Prostate Cancer

The histopathologic and molecular heterogeneity of prostate cancer and the limited availability of human tumor tissue make unraveling the mechanisms of prostate carcinogenesis a challenging task. Our goal was to develop an ex vivo model that could be reliably used to define a prognostic signature based on gene expression profiling of cell cultures that maintained the tumor phenotype. To this end, we derived epithelial cultures from tissue explanted from 59 patients undergoing radical prostatectomy or cistoprostatectomy because of prostate benign hyperplasia/prostate cancer or bladder carcinoma. Patient selection criteria were absence of hormonal neoadjuvant treatment before surgery and diagnosis of clinically localized disease. Using this unique experimental material, we analyzed expression of 22,500 transcripts on the Affymetrix Human U133A GeneChip platform (Affymetrix, Inc., High Wycombe, United Kingdom). Cultures from normal/hyperplastic tissues with a prevalent luminal phenotype and from normal prostate epithelial tissue with basal phenotype (PrEC) served as controls. We have established a large number of prostate primary cultures highly enriched in the secretory phenotype. From them, we derived an epithelial-restricted transcriptional signature that (a) differentiated normal from tumor cells and (b) clearly separated cancer-derived lines into two distinct groups, which correlated with indolent or aggressive clinical behavior of the disease. Our findings provide (a) a method to expand human primary prostate carcinoma cells with a luminal phenotype, (b) a powerful experimental model to study primary prostate cancer biology, and (c) a novel means to characterize these tumors from a molecular genetic standpoint for prognostic and/or predictive purposes.

Bladder cancer, a two phased disease?

The processes of intraepithelial migration, intraluminal seeding, and field cancerization as models for initiation, spread, and recurrences of urothelial cell carcinoma (UCC) are reviewed in light of recent molecular investigations. The accumulated molecular data on synchronous and metachronous tumors indicate that the majority of recurrent and multiple tumors are monoclonal. Molecular data has also shown the presence of chromosomal and genetic changes in precursor lesions as well as in normal urothelial cells. Genetic-histological mapping of cystectomized bladders has shown that overt tumors occur as local events in areas of genetically altered urothelium. A model is put forward in which the tumor process is initiated by genetically altered but histologically normal cells that produce fields of altered cells by intraepithelial displacement. By the accumulation of further genetic changes the fields of altered urothelium reaches a state of criticality, which locally may produce frank tumors.

Origin of multifocal carcinomas of the bladder and upper urinary tract: molecular analysis and clinical implications

The simultaneous or metachronous development of multifocal tumors with identical or variable histological features in the urothelial tract in a single patient is a well-known characteristic of urothelial cancer. To explain this phenomenon, two distinct concepts have been proposed: the 'field defect' hypothesis according to which urothelial cells in patients are primed to undergo transformation by previous carcinogenic insults and the 'single progenitor cell' hypothesis, which asserts that the multifocal development is caused by the seeding or intraepithelial spread of transformed cells. Results of recent molecular genetic studies support the 'single progenitor cell' hypothesis, and indicate that the genetic and phenotypic diversity observed in multifocal urothelial tumors is a consequence of clonal evolution from a single transformed cell. An understanding of the mechanism of the heterotopic recurrence of urothelial cancer may provide new prospects for early molecular detection and prevention of heterotopic recurrence of urothelial cancer.

Molecular evidence supporting field effect in urothelial carcinogenesis

PURPOSE

Human urothelial carcinoma is thought to arise from a field change that affects the entire urothelium. Multifocality of urothelial carcinoma is a common finding at endoscopy and surgery. Whether these coexisting tumors arise independently or are derived from the same tumor clone is uncertain. Molecular analysis of microsatellite alterations and X-chromosome inactivation status in the cells from each coexisting tumor may further our understanding of urothelial carcinogenesis.

EXPERIMENTAL DESIGN

We examined 58 tumors from 21 patients who underwent surgical excision for urothelial carcinoma. All patients had multiple separate foci of urothelial carcinoma (two to four) within the urinary tract. Genomic DNA samples were prepared from formalin-fixed, paraffin-embedded tissue sections using laser-capture microdissection. Loss of heterozygosity (LOH) assays for three microsatellite polymorphic markers on chromosome 9p21 (IFNA and D9S171), regions of putative tumor suppressor gene p16, and on chromosome 17p13 (TP53), the p53 tumor suppressor gene locus, were done. X-chromosome inactivation analysis was done on the urothelial tumors from 11 female patients.

RESULTS

Seventeen of 21 (81%) cases showed allelic loss in one or more of the urothelial tumors in at least one of the three polymorphic markers analyzed. Concordant allelic loss patterns between each coexisting urothelial tumor were seen in only 3 of 21 (14%) cases. A concordant pattern of nonrandom X-chromosome inactivation in the multiple coexisting urothelial tumors was seen in only 3 of 11 female patients; of these 3 cases, only one displayed an identical allelic loss pattern in all of the tumors on LOH analysis.

CONCLUSION

LOH and X-chromosome inactivation assays show that the coexisting tumors in many cases of multifocal urothelial carcinoma have a unique clonal origin and arise from independently transformed progenitor urothelial cells, supporting the "field effect" theory for urothelial carcinogenesis.

Cytogenetic profiles as additional markers to pathological features in clinically localized prostate carcinoma

Fluorescence in situ hybridization analysis for evaluation of 7, 8, X chromosomes and EGFR, LPL, MYC, AR genes in 79 neoplastic foci from 56 patients with clinically localized prostate cancer was performed. We found aneusomy for chromosome 7, 8 and X in 74/77 (96.1%), 56/76 (73.7%), 26/70 (37.1%) of examined foci respectively. No specimen was amplified for EGFR and AR genes, only 2/71 (2.8%) specimens showed MYC gene amplified. LPL deletion was present in 52/76 (68.4%) specimens. Statistically association between Gleason score and both chromosome 7 aneusomy and 8p21 deletion was present. The frequency of chromosome 7 aneusomy was statistically higher in T3-4 cases than T2c and T2a-T2b ones. We considered as unfavorable a genetic set if aneusomy for at least two chromosomes and one altered gene were present. The percentage of tumors, with unfavorable genetic pattern, increased from 36.4 to 75.0% in those with Gleason >7 and from 40.0 to 73.7% in those with stage T3 or more. These alterations could be considered potent genetic markers adjunctive to conventional prognostic parameters. Our objective was to establish specific genetic profiles which may discriminate favorable and unfavorable genetic prognosis tumors.

Status of the p53, p16, RB1, and HER-2 genes and chromosomes 3, 7, 9, and 17 in advanced bladder cancer: correlation with adjacent mucosa and pathological parameters

AIMS

To evaluate a panel of well known genetic alterations for frequency of changes in bladder cancer that could be considered genomic instability determinants or adjunctive prognostic predictors.

METHODS

Fluorescence in situ hybridisation analysis was performed to evaluate chromosomes 3, 7, 9, and 17 and the 9p21 (p16), 17p13.1 (p53), 13q14 (RB1), and 17q11.2 (HER-2) chromosomal loci in 48 muscle invasive bladder cancer specimens and the adjacent normal mucosa.

RESULTS

There were significant differences between the frequency of chromosome 7 monosomy/polysomy and 17 monosomy in the two groups (tumours and adjacent mucosa) (p = 0.004, p = 0.037, and p = 0.015, respectively). There were no differences in the frequency of gene deletions between tumours and the adjacent mucosa. 17q11.2 amplification was found in 14.5% of tumours examined, but not in the non-malignant epithelium. Chromosome 3, 7, and 17 monosomy and the RB1 heterozygous deletion were significantly associated with stage T3-4 (p = 0.03, p = 0.04, p = 0.04, and p = 0.03, respectively).

CONCLUSIONS

These results demonstrate the importance of chromosomes 3, 7, and 17 and gene alterations in bladder cancer progression, highlighting their usefulness as prognostic markers. Larger studies with longterm follow up of these patients are needed to determine the validity and clinical relevance of these genetic findings, and molecular prognostic markers should be incorporated into phase II and III trials to define their roles in predicting clinical outcome.

Genetic and pathologic significance of 1p, 17p, and 18q aneusomy and the ERBB2 gene in colorectal cancer and related normal colonic mucosa

Among chromosome defects in colon cancer, deletions in 1p, 17p, and 18q have been reported as frequent events. To verify this, we investigated 1p, 17p, and 18q aneusomy in 60 colorectal cancers and their surrounding mucosa by means of fluorescence in situ hybridization (FISH). We also evaluated ERBB2 gene (alias HER-2/neu) amplification in a subset of tumors. The genetic picture in tumors was correlated with chromosomal alterations in normal colonic mucosae, as well with clinicopathologic variables. A population of cells in morphologically normal epithelium possesses genetic aberrations common to those in colon cancer, although in different percentages. No significant difference emerged in terms of fraction of nuclei with 17p monosomy between primary tumors and distal mucosal samples. Of tumor samples aneusomic for the three chromosomes, 58.3% also showed aneusomy in related normal colonic mucosa. In neoplastic samples, significant correlation existed between 1p aneusomy and mucosal component (P<0.007), between 17p aneusomy and increased depth of invasion (T3-T4) (P<0.05), and between 18q aneusomy and tumor site (P<0.03). None of the evaluated samples, neoplastic or normal, showed ERBB2 gene amplification.