Chromosome 9 deletions and recurrence of superficial bladder cancer: identification of four regions of prognostic interest

Loss of MTAP Expression by Immunohistochemistry Is a Surrogate Marker for Homozygous 9p21.3 Deletion in Urothelial Carcinoma

Homozygous deletion of the chromosomal region 9p21.3 is common in urothelial carcinoma (UC) and leads to loss of several genes, including CDKN2A and MTAP, resulting in loss of MTAP protein expression. Here, we aimed to explore the diagnostic potential of MTAP immunohistochemistry (IHC) as a surrogate marker for homozygous 9p21.3 deletion (9p21 homozygous deletion [HD]) in UC. MTAP status was determined by IHC on 27 UC tissue specimens with known 9p21.3 status as defined by fluorescence in situ hybridization in matched cytological specimens, by IHC and fluorescence in situ hybridization on a tissue microarray (TMA) containing 359 UC at different stages, and by IHC on 729 consecutive UC from routine practice. Moreover, we analyzed a longitudinal series of matched specimens from 38 patients with MTAP-negative recurrent UC. MTAP loss by IHC was found in all 17 patients with 9p21 HD and in 2/8 cases without 9p21 HD. In the TMA, MTAP loss was more common in metastases (53%) than in muscle-invasive (33%) and non-muscle-invasive UC (29%) (P = .03). In the consecutive series, 164/729 (22%) cases showed loss of MTAP expression. In 41 of these 164 cases (25%), loss of MTAP expression was heterogenous. We also discovered loss of MTAP expression in flat urothelium adjacent to MTAP-negative low-grade UC, suggesting true flat low-grade neoplasia that could not be diagnosed by morphology alone. Longitudinal analysis of recurrences showed persistent negative MTAP status over time in 37/38 (97%) patients. MTAP IHC can serve as a surrogate marker for 9p21 HD in UC and as a diagnostic tool to differentiate reactive urothelium from urothelial neoplasia. It also provides a unique opportunity to study clinicopathological associations and the heterogeneity of 9p21 HD across the whole spectrum of UC manifestations.

MTAP deficiency creates an exploitable target for antifolate therapy in 9p21-loss cancers

Methylthioadenosine phosphorylase, an essential enzyme for the adenine salvage pathway, is often deficient (MTAPdef) in tumors with 9p21 loss and hypothetically renders tumors susceptible to synthetic lethality by antifolates targeting de novo purine synthesis. Here we report our single arm phase II trial (NCT02693717) that assesses pemetrexed in MTAPdef urothelial carcinoma (UC) with the primary endpoint of overall response rate (ORR). Three of 7 enrolled MTAPdef patients show response to pemetrexed (ORR 43%). Furthermore, a historic cohort shows 4 of 4 MTAPdef patients respond to pemetrexed as compared to 1 of 10 MTAP-proficient patients. In vitro and in vivo preclinical data using UC cell lines demonstrate increased sensitivity to pemetrexed by inducing DNA damage, and distorting nucleotide pools. In addition, MTAP-knockdown increases sensitivity to pemetrexed. Furthermore, in a lung adenocarcinoma retrospective cohort (N = 72) from the published BATTLE2 clinical trial (NCT01248247), MTAPdef associates with an improved response rate to pemetrexed. Our data demonstrate a synthetic lethal interaction between MTAPdef and de novo purine inhibition, which represents a promising therapeutic strategy for larger prospective trials.

The Prognostic Role of CDK9 in Bladder Cancer

Introduction: Most patients with urothelial carcinoma are diagnosed with non-invasive tumors, but the prognosis worsens with the progression of the disease. Overexpression of cyclin-dependent kinase 9 has been recently linked to increased cancer proliferation, faster progression, and worse prognosis. However, some cancers seem to contradict this rule. In this work, we explored the prognostic role of CDK9 expression in urothelial carcinoma. Materials and Methods: We performed immunohistochemical analysis on 72 bladder cancer samples. To assess a larger group of patients, the Cancer Genome Atlas (TCGA) database containing 406 cases and transcriptomics information through the Human Pathology Atlas were analyzed. Results: CDK9 is overexpressed in urothelial cancer tissues when compared to normal urothelial tissues (p < 0.05). High CDK9 expression was observed in low-stage, low-grade, and non-muscle-invasive tumors (p < 0.05). The patients with high CDK9 expression had a significantly higher 5-year overall survival rate than those with low CDK9 expression (77.54% vs. 53.6% in the TMA group and 57.75% vs. 35.44% in the TCGA group, respectively) (p < 0.05). The results were consistent in both cohorts. Multivariate Cox regression analysis indicated that low CDK9 status was an independent predictor for poor prognosis in the TCGA cohort (HR 1.60, CL95% 1.1−2.33, p = 0.014). Conclusions: High CDK9 expression predicts a favorable prognosis in urothelial carcinoma and is associated with clinicopathological features characteristic for early-stage disease. The decrease in CDK9 expression can be associated with the build-up of genetic instability and may indicate a key role for CDK9 in the early stages of urothelial carcinoma.

Characteristics of upper urinary tract urothelial carcinoma in the context of bladder cancer: a narrative review

Urothelial carcinomas (UC) arise from the urothelium that covers the proximal urethra, urinary bladder, and the upper urinary tract. In daily routine and clinical trials UC originating from different locations are often treated and investigated in the same manner. However, differences between the two locations seem to be apparent and may question in handling them as a single oncologic entity. In this review we discuss similarities and differences between bladder and upper urinary tract UC and consider their potential impact on treatment strategies. Despite similarities of UC in the bladder (BC) and the upper urinary tract (UTUC), clinicopathologic and molecular differences may question to generally assemble both as a single tumor entity. Treatment standards for UTUC are often adopted from BC. However, a specific investigation in the former may still be meaningful as shown by the example of adjuvant cisplatin based chemotherapy. In conclusion, future investigations should prioritize the understanding of the tumor biology of both BC and UTUC. This may reveal which UTUC can be treated according to treatment standards of BC and in which cases, a separate approach may be more appropriate.

VNTR polymorphism in the breakpoint region of ABL1 and susceptibility to bladder cancer

BACKGROUND

ABL1 is primarily known as a leukemia-related oncogene due to translocation, but about 2.2% of ABL1 mutations have been identified in bladder cancer, and high expression in solid cancer has also been detected.

METHODS

Here, we used the NCBI database, UCSC genome browser gateway and Tandem repeat finder program to investigate the structural characterization of the ABL1 breakpoint region and to identify the variable number of tandem repeats (VNTR). To investigate the relationship between ABL1-MS1 and bladder cancer, a case-controlled study was conducted in 207 controls and 197 bladder cancer patients. We also examined the level of transcription of the reporter gene driven by the ABL1 promoter to determine if the VNTR region affects gene expression.

RESULTS

In our study, one VNTR was identified in the breakpoint region, the intron 1 region of ABL1, and was named ABL1-MS1. In the control group, only two common alleles (TR13, TR15) were detected, but an additional two rare alleles (TR14, TR16) were detected in bladder cancer. A statistically significant association was identified between the rare ABL1-MS1 allele and bladder cancer risk: P = 0.013. Investigating the level of transcription of the reporter gene driven by the ABL1 promoter, VNTR showed inhibition of ABL1 expression in non-cancer cells 293 T, but not in bladder cancer cells. In addition, ABL1-MS1 was accurately passed on to offspring according to Mendelian inheritance through meiosis.

CONCLUSIONS

Therefore, the ABL1-MS1 region can affect ABL1 expression of bladder cancer. This study provides that ABL1-MS1 can be used as a DNA fingerprinting marker. In addition, rare allele detection can predict susceptibility to bladder cancer.

Beyond BCG: the approaching era of personalised bladder-sparing therapies for non-muscle-invasive urothelial cancers

Progress in the management of non-muscle invasive bladder cancer has been slow. Despite longstanding use of intravesical therapies (e.g., Bacille Calmette-Guerin; BCG) to complement cystoscopic resection of high-grade lesions, many patients still develop recurrences requiring cystectomy, while others suffer side-effects of BCG without definite benefit. Many questions remain: for example, how many patients receive intravesical prophylaxis without efficacy? Which high-risk patients are best managed with early cystectomy? Could systemic therapies and/or radiotherapy extend bladder preservation times? Such questions may soon be refined by clinicopathologic non-muscle invasive bladder cancer signatures that predict sensitivity to cytotoxic, immune and targeted therapies. Hypothesis-based trials using these signatures should lead to more rational adjuvant treatments, longer bladder preservation times, and better quality of life for patients.

Auxiliary diagnostic value of p16 amplification combined with the detection of heterozygous and homozygous loss for urothelial carcinoma

The present study aimed to investigate the significance of detecting cyclin dependent kinase inhibitor 2A (p16) gene aberrations in the diagnosis of urothelial carcinoma (UC) using fluorescence in situ hybridization (FISH). A total of 77 voided urine specimens from 65 patients with UC and 12 patients with benign urinary disease were recruited into the current study. Under a fluorescence microscope, cells with large and irregular nuclei were assessed for chromosomal aberrations. The positive rate of p16 amplification in UC samples was 32.3% (21/65), which was significantly higher than that in benign urinary disease samples (16.7%, 2/12; P<0.05). Heterozygous and homozygous loss of p16 was identified in 12 (18.5%) and 23 (35.4%) patients with UC, respectively; p16 expression in the remainder of patients was normal. In addition, as tumor stage or grade advanced, the positive rate of p16 aberrations also increased significantly (P<0.05). In conclusion, p16 gene aberrations may serve important roles in the auxiliary diagnosis of UC by FISH and could be utilized to monitor UC progression.

Genetic and Epigenetic Alterations in Bladder Cancer

Bladder cancer is one of the most common cancers worldwide, with a high rate of recurrence and poor outcomes as a result of relapse. Bladder cancer patients require lifelong invasive monitoring and treatment, making bladder cancer one of the most expensive malignancies. Lines of evidence increasingly point to distinct genetic and epigenetic alteration patterns in bladder cancer, even between the different stages and grades of disease. In addition, genetic and epigenetic alterations have been demonstrated to play important roles during bladder tumorigenesis. This review will focus on bladder cancer-associated genomic and epigenomic alterations, which are common in bladder cancer and provide potential diagnostic markers and therapeutic targets for bladder cancer treatment.

ABO blood groups in relation to breast carcinoma incidence and associated prognostic factors in Moroccan women

The association between blood groups ABO and different types of diseases was established in several previous studies. Our aim was to seek the possible association between the ABO blood group and breast cancer-associated prognostic factors. The Chi-squared analytic test was used to compare phenotypic ABO distribution among Moroccan blood donors and 442 cases of women suffering from breast carcinoma with archived files in Maternity Ward of University Hospital C.H.U Ibn Rochd between 2008 and 2011. High incidence of breast carcinoma was observed in blood type B patients (p < 0.05). Blood type B was associated with breast carcinomas overexpressing human epidermal growth factor receptor HER2 (p < 0.05) and high risk of cancer at age over 70 years (p < 0.001). Blood type A was associated with high risk of cancer among women younger than 35 years old. Blood type A and AB were associated with high incidence of lymph node metastasis (p < 0.05). Multivariate analysis has shown correlation between O blood type and estrogen receptor-positive tumor. Patients with blood group A, B, and AB were more likely to develop aggressive breast carcinoma. Further follow-up studies are necessary to clarify the role of ABH antigens in the progression of breast carcinoma.

Canine urothelial carcinoma: genomically aberrant and comparatively relevant

Urothelial carcinoma (UC), also referred to as transitional cell carcinoma (TCC), is the most common bladder malignancy in both human and canine populations. In human UC, numerous studies have demonstrated the prevalence of chromosomal imbalances. Although the histopathology of the disease is similar in both species, studies evaluating the genomic profile of canine UC are lacking, limiting the discovery of key comparative molecular markers associated with driving UC pathogenesis. In the present study, we evaluated 31 primary canine UC biopsies by oligonucleotide array comparative genomic hybridization (oaCGH). Results highlighted the presence of three highly recurrent numerical aberrations: gain of dog chromosome (CFA) 13 and 36 and loss of CFA 19. Regional gains of CFA 13 and 36 were present in 97 % and 84 % of cases, respectively, and losses on CFA 19 were present in 77 % of cases. Fluorescence in situ hybridization (FISH), using targeted bacterial artificial chromosome (BAC) clones and custom Agilent SureFISH probes, was performed to detect and quantify these regions in paraffin-embedded biopsy sections and urine-derived urothelial cells. The data indicate that these three aberrations are potentially diagnostic of UC. Comparison of our canine oaCGH data with that of 285 human cases identified a series of shared copy number aberrations. Using an informatics approach to interrogate the frequency of copy number aberrations across both species, we identified those that had the highest joint probability of association with UC. The most significant joint region contained the gene PABPC1, which should be considered further for its role in UC progression. In addition, cross-species filtering of genome-wide copy number data highlighted several genes as high-profile candidates for further analysis, including CDKN2A, S100A8/9, and LRP1B. We propose that these common aberrations are indicative of an evolutionarily conserved mechanism of pathogenesis and harbor genes key to urothelial neoplasia, warranting investigation for diagnostic, prognostic, and therapeutic applications.

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.

MicroRNA-126 inhibits invasion in bladder cancer via regulation of ADAM9

Background:

The miRNA deregulation is commonly observed in human malignancies, where they act as tumour suppressors or oncogenes. Despite the association of several miRNAs with bladder cancer, little is known about the miRNAs that contribute to bladder cancer progression from non-muscle invasive (NMI) to muscle-invasive (MI) disease.

Methods:

We first profiled the expression of miRNAs and mRNAs in a cohort of urothelial carcinomas and further characterised the role of miR-126 in invasion, as it emerged as the most downregulated miRNA between MI and NMI tumours.

Results:

We found that restoration of miR-126 levels attenuated the invasive potential of bladder cancer cells. Mechanistically, we identified the role of miR-126 in invasion through its ability to target ADAM9. Notably, a significant inverse correlation between miR-126 and ADAM9 expression was observed, where ADAM9 was upregulated in MI bladder cancer cells. While knockdown of ADAM9 attenuated the invasiveness of cells with low miR-126 levels, experimental upregulation of ADAM9 recapitulated the invasive phenotype. Furthermore, ADAM9 expression assessed by immunohistochemistry significantly correlated with poor prognosis in patients with urothelial carcinoma.

Conclusions:

In this study we describe the role of miR-126 in bladder cancer progression, identifying miR-126 and ADAM9 as potential clinical biomarkers of disease aggressiveness.

Common chromosome fragile sites in human and murine epithelial cells and FHIT/FRA3B loss-induced global genome instability

Chromosomal positions of common fragile sites differ in lymphoblasts and fibroblasts, with positions dependent on the epigenetically determined density of replication origins at these loci. Because rearrangement of fragile loci and associated loss of fragile gene products are hallmarks of cancers, we aimed to map common fragile sites in epithelial cells, from which most cancers derive. Among the five most frequently activated sites in human epithelial cells were chromosome bands 2q33 and Xq22.1, which are not among top fragile sites identified in lymphoblasts or fibroblasts. FRA16D at 16q23 was among the top three fragile sites in the human epithelial cells examined, as it is in lymphoblasts and fibroblasts, while FRA3B at 3p14.2, the top fragile locus in lymphoblasts, was not fragile in most epithelial cell lines tested. Epithelial cells exhibited varying hierarchies of fragile sites; some frequent epithelial cell fragile sites are apparently not frequently altered in epithelial cancers and sites that are frequently deleted in epithelial cancers are not necessarily among the most fragile. Since we have reported that loss of expression of the FRA3B-encoded FHIT protein causes increased replication stress-induced DNA damage, we also examined the effect of FHIT-deficiency on markers of genome instability in epithelial cells. FHIT-deficient cells exhibited increases in fragile breaks and in γH2AX and 53BP1 foci in G1 phase cells, confirming in epithelial cells that the FHIT gene and encompassing FRA3B, is a "caretaker gene" necessary for maintenance of genome stability.

Bladder cancer: a simple model becomes complex

Bladder cancer is one of the most frequent malignancies in developed countries and it is also characterized by a high number of recurrences. Despite this, several authors in the past reported that only two altered molecular pathways may genetically explain all cases of bladder cancer: one involving the FGFR3 gene, and the other involving the TP53 gene. Mutations in any of these two genes are usually predictive of the malignancy final outcome. This cancer may also be further classified as low-grade tumors, which is always papillary and in most cases superficial, and high-grade tumors, not necessarily papillary and often invasive. This simple way of considering this pathology has strongly changed in the last few years, with the development of genome-wide studies on expression profiling and the discovery of small non-coding RNA affecting gene expression. An easy search in the OMIM (On-line Mendelian Inheritance in Man) database using "bladder cancer" as a query reveals that genes in some way connected to this pathology are approximately 150, and some authors report that altered gene expression (up- or down-regulation) in this disease may involve up to 500 coding sequences for low-grade tumors and up to 2300 for high-grade tumors. In many clinical cases, mutations inside the coding sequences of the above mentioned two genes were not found, but their expression changed; this indicates that also epigenetic modifications may play an important role in its development. Indeed, several reports were published about genome-wide methylation in these neoplastic tissues, and an increasing number of small non-coding RNA are either up- or down-regulated in bladder cancer, indicating that impaired gene expression may also pass through these metabolic pathways. Taken together, these data reveal that bladder cancer is far to be considered a simple model of malignancy. In the present review, we summarize recent progress in the genome-wide analysis of bladder cancer, and analyse non-genetic, genetic and epigenetic factors causing extensive gene mis-regulation in malignant cells.

Association of copy number loss of CDKN2B and PTCH1 with poor overall survival in patients with pulmonary squamous cell carcinoma

BACKGROUND AND PURPOSE

Although lung cancer is the leading cause of cancer deaths worldwide, reliable markers allowing prediction of patient survival at the time of initial diagnosis are still lacking. Copy number alterations (CNAs) in tumor tissue DNA have been associated with tumorigenesis and malignant progression. We aimed at identification of gene-level CNAs with prognostic value for survival in pulmonary squamous cell carcinoma (SCC).

METHODS

The CNA status of a panel of 44 genes was analyzed by high-resolution array comparative genomic hybridization (CGH) in 49 SCC samples. Overall survival information (median follow-up, 40 months) for the patients was collected and used to assess outcome correlations with gene CNAs.

RESULTS

Survival analysis showed that both CDKN2B loss and PTCH1 loss were associated with poor survival (both P < .001, log-rank test). Multivariate Cox analysis, including CDKN2B loss and PTCH1 loss as well as age, sex, cigarette smoking status, tumor size, tumor differentiation, and TNM stage showed that CDKN2B loss (hazard ratio [HR], 17.88; 95% confidence interval [CI], 4.40-72.67; P < .001) and PTCH1 loss (HR, 10.81; 95% CI, 1.92-60.98; P = .007) were independent prognostic factors for poor survival. In addition the PTCH1 loss was more frequently found in moderately or poorly differentiated tumors than in well-differentiated tumors (P = .007).

CONCLUSION

These findings suggest that 2 genes of loss, CDKN2B and PTCH1, are associated with poor overall survival in patients with SCC of the lung and may be useful as prognostic markers.

Bladder cancer or bladder cancers? Genetically distinct malignant conditions of the urothelium

Despite the fact that the current histopathologic classification for bladder cancer has led to improved concepts for the clinical management of the disease, key questions with regard to assessment of risk for recurrence and/or progression to invasive disease remain. In addition, response to specific therapies cannot be predicted accurately. Bladder tumors comprise a heterogeneous group with respect to both histopathology and clinical behavior. Thus, it is anticipated that a thorough knowledge and interpretation of the molecular alterations involved in tumor development and progression will lead to greater prognostic and predictive power. This may not only lead to better comprehension of the biology of the disease, but may also lead to the development of novel individualized therapies. Novel means of stratification are urgently needed to provide a new subclassification of urothelial lesions. This review discusses and summarizes the genetic alterations that have been reported in bladder cancer and relates these to the current 2-pathway model for tumor development. The molecular pathogenesis of high-grade noninvasive papillary tumors and of T1 tumors is not yet clear, and possibilities are discussed.

Molecular determinants of tumor recurrence in the urinary bladder

Tumor recurrence is a major clinical concern for patients with urothelial carcinoma of the urinary bladder. Traditional morphological analysis is of limited utility for identifying cases in which recurrence will occur. However, molecular and genetic analyses offer new perspectives on the prediction of bladder tumor recurrence. Recent studies have suggested that urothelial carcinogenesis occurs as a 'field effect' that can involve any number of sites in the bladder mucosa. Accumulating evidence supports the notion that resident urothelial stem cells in the affected field are transformed into cancer stem cells by acquiring genetic alterations that lead to tumor formation through clonal expansion. Both initial and recurrent tumors are derived from cancer stem cells in the affected field via two distinct molecular pathways. These provide a genetic framework for understanding urothelial carcinogenesis, tumor recurrence and progression: the FGFR3-associated pathway and the TP53-associated pathway. These two pathways are characterized by different genomic, epigenetic and gene-expression alterations. Their outcomes correlate with the markedly different clinical and pathologic features of both relatively indolent low-grade cancers and the aggressive high-grade cancers. As such, these molecular findings are potentially useful for counseling patients and for assessing risk of recurrence or biological aggressiveness of the patient's tumor. The molecular changes may additionally prove useful for developing preventive and therapeutic strategies for urothelial bladder cancer. A unifying model of urothelial carcinogenesis, tumor recurrence and progression is proposed in this review.

Alterations in candidate genes PHF2, FANCC, PTCH1 and XPA at chromosomal 9q22.3 region: pathological significance in early- and late-onset breast carcinoma

Introduction

Younger women with breast carcinoma (BC) exhibits more aggressive pathologic features compared to older women; young age could be an independent predictor of adverse prognosis. To find any existing differences in the molecular pathogenesis of BC in both younger and older women, alterations at chromosomal (chr.) 9q22.32-22.33 region were studied owing to its association in wide variety of tumors. Present work focuses on comparative analysis of alterations of four candidate genes; PHF2, FANCC, PTCH1 and XPA located within 4.4 Mb region of the afore-said locus in two age groups of BC, as well as the interrelation and prognostic significance of alterations of these genes.

Methods

Deletion analysis of PHF2, FANCC, PTCH1 and XPA were examined in a subset of 47 early-onset (group-A: ≤ 40 years) and 59 late-onset (group-B: > 40 years) breast carcinomas using both microsatellite and exonic markers. Methylation Sensitive Restriction analysis (MSRA) was done to check for promoter methylation. Quantitative real-time polymerase chain reaction (Q-PCR) and immunohistochemisty (IHC) was done in some genes to see their relative mRNA and protein expressions respectively. Clinico-pathological correlation of different parameters as well as patient survival was calculated using different statistical softwares like EpiInfo 6.04b, SPSS 10.0 etc.

Results

Either age group exhibited high frequency of overall alterations in PHF2, FANCC and PTCH1 compared to XPA. Samples with alteration (deletion/methylation) in these genes showed reduced level of mRNA expression as seen by Q-PCR. Immunohistochemical analysis of FANCC and PTCH1 also supported this observation. Poor patient survival was noted in both age groups having alterations in FANCC. Similar result was also seen with PTCH1 and XPA alterations in group-A and PHF2 alterations in group-B. This reflected their roles as prognostic tools in the respective groups in which they were altered.

Conclusion

Overall alterations of PHF2, FANCC and PTCH1 were comparatively higher than XPA. Differential association of alterations in FANCC and PTCH1 with that of PHF2, XPA and two breast cancer susceptibility genes (BRCA1/BRCA2) in the two age groups suggests differences in their molecular pathogenesis and dysregulation of multiple DNA repair pathways as well as hedgehog dependent stem cell renewal pathway.

Molecular pathogenesis of bladder cancer

Bladder tumors show widely differing histopathology and clinical behavior. This is reflected in the molecular genetic alterations they contain. Much information has accumulated on somatic genomic alterations in bladder tumors of all grades and stages and when this information is related to the common histopathological appearances, a model for the pathogenesis of two major groups of bladder tumors has emerged. This review summarizes the genetic alterations that have been reported in bladder cancer and relates these to the current two-pathway model for tumor development. The molecular pathogenesis of high-grade noninvasive papillary tumors and of T1 tumors is not yet clear and possibilities are discussed.

Aminopeptidase O contains a functional nucleolar localization signal and is implicated in vascular biology

We have identified a gene trap integration into Aminopeptidase O, the gene encoding a member of the M1 family of metalloproteases. Using the betagal reporter of the gene trap vector, we have revealed that at least some ApO isoforms are expressed predominantly in embryonic and adult blood vessels leading us to propose that ApO plays a role in vascular cell biology. The protein produced from an engineered Gfp-ApO fusion cDNA localises to the nucleolus in transfected COS7 cells. We confirm that indeed the APO protein contains a functional nucleolar localisation domain by demonstrating that GFP-APO fusion proteins that lack the predicted nucleolar localisation signal are retained in the cytoplasm. We report the existence of multiple alternatively spliced Apo isoforms that differ with respect to the presence of exons encoding important functional domains. Alternative splicing predictably produces protein products with or without the catalytic domain and/or a nucleolar localisation signal and therefore likely represents an important mechanism in regulating the biological activity of APO that has been reported to cleave one of the peptides of the renin angiotensin pathway.

The genetics of bladder cancer: a cytogeneticist's perspective

Cytogenetic studies of bladder cancer have helped to define two clinically distinct subtypes: benign tumors with few genetic mutations and a stable karyotype and aggressive cancers with chromosomal instability and many non-random cytogenetic aberrations. While the cytogenetic data does not provide complete information, these studies have been important for suggesting pathways for bladder carcinoma initiation and its progression. In addition, molecular cytogenetic studies have proven useful for diagnosing bladder cancer and for monitoring patients for cancer recurrence. More detailed molecular genetic studies and expression array analyses are needed to fully comprehend the biologic processes associated with urothelial cancers, but cytogenetics studies have laid the foundation for further investigation.

RRIG1 mediates effects of retinoic acid receptor beta2 on tumor cell growth and gene expression through binding to and inhibition of RhoA

The expression of retinoic acid receptor beta2 (RAR-beta2) is frequently lost in various cancers and their premalignant lesions. However, the restoration of RAR-beta2 expression inhibits tumor cell growth and suppresses cancer development. To understand the molecular mechanisms responsible for this RAR-beta2-mediated antitumor activity, we did restriction fragment differential display-PCR and cloned a novel retinoid receptor-induced gene 1 (RRIG1), which is differentially expressed in RAR-beta2-positive and RAR-beta2-negative tumor cells. RRIG1 cDNA contains 2,851 bp and encodes a protein with 276 amino acids; the gene is localized at chromosome 9q34. Expressed in a broad range of normal tissues, RRIG1 is also lost in various cancer specimens. RRIG1 mediates the effect of RAR-beta2 on cell growth and gene expression (e.g., extracellular signal-regulated kinase 1/2 and cyclooxygenase-2). The RRIG1 protein is expressed in the cell membrane and binds to and inhibits the activity of a small GTPase RhoA. Whereas induction of RRIG1 expression inhibits RhoA activation and f-actin formation and consequently reduces colony formation, invasion, and proliferation of esophageal cancer cells, antisense RRIG1 increases RhoA activity and f-actin formation and thus induces the colony formation, invasion, and proliferation of these cells. Our findings therefore show a novel molecular pathway involving RAR-beta2 regulation of RRIG1 expression and RRIG1-RhoA interaction. An understanding of this pathway may translate into better control of human cancer.

Bladder cancer diagnosis and recurrence prognosis: Comparison of markers with emphasis on survivin

Expression of the anti-apoptotic protein survivin is hardly detectable or even absent in many differentiated adult tissues, but is upregulated in almost any type of cancer. Furthermore, high survivin mRNA or protein expression generally correlates with an adverse disease course. Both these important features of survivin expression have been investigated for diagnostic and prognostic purposes in many human cancers, including bladder cancer. In this review, the role of survivin in the detection of bladder tumors and the prediction of tumor recurrence in patients with superficial bladder cancer will be discussed and compared to that of other markers/tests. The most promising marker(s) will be outlined. Also, important requirements for a successful implementation of such markers in a hospital setting are discussed. Finally, future directions for the discovery of new diagnostic or prognostic candidate markers will be mentioned.

Allelic loss at Drosophila patched gene is highly prevalent in Basal and squamous cell carcinomas of the skin

The human homolog of the Drosophila Patched gene (PTCH), located at chromosome 9q22.3, is frequently altered in both nevoid basal cell carcinoma syndrome, and sporadic basal cell carcinomas (BCCs). However, alteration of the PTCH gene locus has been poorly studied in squamous cell carcinoma (SCC). We analyzed loss of heterozygosity (LOH) at five markers in and around the PTCH gene in 276 keratinocyte tumors from a population-based study in New Hampshire. We found a high prevalence of any 9q22.3 LOH in both BCC (75.5%) and SCC (60.8%), with BCC being significantly more likely to have LOH than SCC (P<0.009). The PTCH gene was specifically lost in 60% of BCC, and 50% of SCC tumors. Among SCC tumors, 9q22 LOH was significantly more likely to occur in those who tend to burn (P<0.05), and this association was strongest for tumors that occurred on sun-exposed areas of the body (P<0.04). Additionally, 9q22 LOH occurred more frequently in SCC tumors associated with a history of severe sunburns (P<0.08). Thus, in our large, population-based sample, 9q22 loss, including PTCH, was highly prevalent in both BCC and SCC. Overall, these data support the hypothesis that PTCH loss is a common, early lesion for SCC and BCC.

Transitional cell bladder tumor: predicting recurrence and progression by analysis of microsatellite loss of heterozygosity in urine sediment and tumor tissue

Transitional cell bladder tumors (TCT) is prone to recurrence (60-80%) after tumor resection. Up to 25% of these patients will progress, so it is important to find reliable predictive markers. We analyzed for loss of heterozygosity (LOH) with respect to 13 microsatellites located on 10 different chromosomal arms. This analysis was performed on the urine sediment and tumor tissue from 59 patients with bladder TCT and on the urine and normal-looking mucosa from 25 patients with a history of bladder TCT but no evidence of disease at the time of the study inclusion. The median follow-up period was 23.1 months (range, 2-48 months) for the 59 patients with bladder TCT and 25 months (range, 4-57 months) for the 25 patients without evidence of ongoing active disease. Correlation between LOH and eventual recurrence, progression, and mortality was investigated. In patients with noninvasive TCT, correlation between 11p tumor tissue LOH and recurrence was found. Similarly, 8p LOH in both urine sediment and tumor tissue correlated with progression. Finally, in the group of patients with a history of bladder TCT, normal tissue 8p and/or 11p LOH correlated with recurrence.

Loss of heterozygosity on chromosome 9q and p53 alterations in human bladder cancer

BACKGROUND

Somatic loss of the 9q allele as well as alteration of the tumor suppressor p53 occurs commonly in bladder cancers. Although alteration of p53 has been strongly associated with invasive stage disease, the prognostic significance of 9q loss of heterozygosity (LOH) and the relations between these alterations are less well defined.

METHODS

The 9q LOH was examined at five microsatellites and p53 alterations (mutation and persistent immunohistochemical staining) in a population-based case series of 271 newly diagnosed bladder cancer patients. Loss of heterozygosity was scored quantitatively and p53 mutation completed using single-strand conformation polymorphism screening followed by sequencing.

RESULTS

Overall, allelic loss at 9q was detected in 74.5% (202/271) of cases and allele loss was associated with invasive disease (P < 0.05). Although based on small numbers, all nine in situ lesions contained 9q LOH. Age, gender, and smoking were not significantly associated with chromosome 9q allele loss. Both intense persistent p53 staining and LOH at 9q were independently associated with invasive disease (P < 10(-14) and P < 0.05, respectively).

CONCLUSIONS

These data, using a population-based sample, suggest a relation between 9q LOH and invasive stage bladder cancer, and thereby suggests that a tumor suppressor gene at this loci, in addition to p53, may be important in the development of this more aggressive form of the disease.

Benzo[a]pyrene diol epoxide-induced 9p21 aberrations associated with genetic predisposition to bladder cancer

CDKN2A, 9p21, encodes two alternatively spiked, functionally distinct, tumor-suppressor proteins, P16INK4A and P14ARF, which play active roles in the RB1 and TP53 pathways, respectively. Deletion of 9p is one of the most frequent genomic alterations in bladder cancer. In addition, alterations of 9p21 and P16 are frequently seen in the epithelial cells of chronic smokers. This pilot study evaluated whether 9p21 aberrations induced by exposure in vitro to benzo[a]pyrene diol epoxide (BPDE), the metabolic product of benzo[a]pyrene, a constituent of tobacco smoke, were more common in the peripheral blood lymphocytes of 61 bladder cancer patients compared to 64 matched controls. Our hypothesis was that 9p21 sensitivity to BPDE reflects the susceptibility of a specific locus to damage from carcinogens in tobacco smoke. We found that BPDE-induced chromosome band 9p21 aberrations were significantly higher in lymphocytes of bladder cancer cases (24.97 +/- 5.26 per 1,000) than in controls (20.72 +/- 4.51 per 1,000; P < 0.0001). However, no difference was observed for CEP9, a control locus. After adjustment for age, sex, ethnicity, and smoking status, 9p BPDE sensitivity had an odds ratio (OR) of 9.01 [95% confidence interval (95% CI) 3.75, 21.67] for bladder cancer. We further observed a gradient of elevated bladder cancer risk associated with increasing chromosomal damage. The adjusted ORs for subjects in the second, third, and highest quartiles of BPDE-induced 9p21 aberrations relative to the first quartile were 0.48 (0.04, 5.69), 5.14 (1.12, 23.59), and 21.51 (4.75, 97.34), respectively, providing increasing dose-response evidence of the locus-specific alterations. Thus, 9p21 may be a molecular target for BPDE-induced damage in bladder cancer cases.

Chromosomal changes in uroepithelial carcinomas

This article reviews and summarizes chromosomal changes responsible for the initiation and progression of uroepithelial carcinomas. Characterization of these alterations may lead to a better understanding of the genetic mechanisms and open the door for molecular markers that can be used for better diagnosis and prognosis of the disease. Such information might even help in designing new therapeutic strategies geared towards prevention of tumor recurrences and more aggressive approach in progression-prone cases.

The revision of 205 cases of uroepithelial carcinomas reported with abnormal karyotypes showed karyotypic profile characterized by nonrandom chromosomal aberrations varying from one or few changes in low-grade and early stage tumors to massively rearranged karyotypes in muscle invasive ones. In general, the karyotypic profile was dominated by losses of chromosomal material seen as loss of entire chromosome and/or deletions of genetic materials. Rearrangements of chromosome 9 resulting in loss of material from 9p, 9q, or of the entire chromosome were the most frequent cytogenetic alterations, seen in 45% of the cases. Whereas loss of material from chromosome arms 1p, 8p, and 11p, and gains of chromosome 7, and chromosome arm 1q, and 8q seem to be an early, but secondary, changes appearing in superficial and well differentiated tumors, the formation of an isochromosome for 5p and loss of material from 17p are associated with more aggressive tumor phenotypes. Upper urinary tract TCCs have identical karyotypic profile to that of bladder TCCs, indicating the same pathogenetic mechanisms are at work in both locales. Intratumor cytogenetic heterogeneity was not seen except in a few post-radiation uroepithelial carcinomas in which distinct karyotypic and clonal pattern were characterized by massive intratumor heterogeneity (cytogenetic polyclonality) with near-diploid clones and simple balanced and/or unbalanced translocations. In the vast majority of cases strong correlation between the tumors grade/stage and karyotypic complexity was seen, indicating that progressive accumulation of acquired genetic alterations is the driving force behind multistep bladder TCC carcinogenesis. Although most of these cytogenetic alterations have been identified for many years, the molecular consequences and relevant cancer genes of these alterations have not yet been identified. However, loss of TSG(s) from chromosome 9 seems to be the primary and important event(s) in uroepithelial carcinogenesis

Identification of Human Aminopeptidase O, a Novel Metalloprotease with Structural Similarity to Aminopeptidase B and Leukotriene A4 Hydrolase

We have cloned and characterized a human brain cDNA encoding a new metalloprotease that has been called aminopeptidase O (AP-O). AP-O exhibits a series of structural features characteristic of aminopeptidases, including a conserved catalytic domain with a zinc-binding site (HEXXHX18E) that allows its classification in the M1 family of metallopeptidases or gluzincins. The structural complexity of AP-O is further increased by the presence of an additional C-terminal domain 170 residues long, which is predicted to have an ARM repeat fold originally identified in the Drosophila segment polarity gene product Armadillo. This ARM repeat domain is also present in aminopeptidase B, aminopeptidase B-like, and leukotriene A4 hydrolase and defines a novel subfamily of aminopeptidases that we have called ARM aminopeptidases. Northern blot analysis revealed that AP-O is mainly expressed in the pancreas, placenta, liver, testis, and heart. Human AP-O was produced in Escherichia coli, and the purified recombinant protein hydrolyzed synthetic substrates used for assaying aminopeptidase activity. This activity was abolished by general inhibitors of metalloproteases and specific inhibitors of aminopeptidases. Recombinant AP-O also cleaved angiotensin III to generate angiotensin IV, a bioactive peptide of the renin-angiotensin pathway with multiple actions on diverse tissues, including brain, testis, and heart. On the basis of these results we suggest that AP-O could play a role in the proteolytic processing of bioactive peptides in those tissues where it is expressed.

Expression in bladder transitional cell carcinoma by real-time quantitative reverse transcription polymerase chain reaction array of 65 genes at the tumor suppressor locus 9q34.1-2: identification of 5 candidates tumor suppressor genes

Frequent deletions on 9q34.1-2 were reported in bladder transitional cell carcinoma. High deletion mapping studies delimited a critical interval between markers D9S61 and D9S66, which is highly susceptible to contain a tumor suppressor gene. Expression level of the 65 genes localized in this region was analyzed by real-time quantitative RT-PCR, comparing tumor to normal urothelium. Five genes exhibited a significantly reduced expression level: C9orf9, KIAA0625, ABL1, LAMC3 and KIAA1857-netrin-G2, which exhibited the most significant downregulation (p=0.0007). KIAA1857-netrin-G2 belongs to the netrins and might then be a tumor suppressor gene in bladder cancer, as netrin1 receptor DCC has been implicated in tumorigenesis.

Recent progress in predictive biomarkers for metastatic recurrence of human hepatocellular carcinoma: a review of the literature

Molecular markers (biomarkers) for hepatocellular carcinoma (HCC) metastasis and recurrence could provide additional information to that gained from traditional histopathological features. A large number of biomarkers have been shown to have potential predictive significance. One important aspect of this is to detect the transcripts of tumor-associated antigens (such as AFP, MAGEs, and CK19), which are proposed as predictive markers of HCC cells disseminated into the circulation and for metastatic recurrence. Another important aspect is to analyze the molecular markers for cellular malignancy phenotype, including DNA ploidy, cellular proliferation index, cell cycle regulators, oncogenes, and tumor suppressors (especially p53 gene), as well as telomerase activity. Molecular factors involved in the process of HCC invasion and metastasis, including adhesion molecules (E-cadherin, catenins, ICAM-1, laminin-5, CD44 variants, osteopontin), proteinases responsible for the degradation of extracellular matrix (MMPs, uPA system), as well as angiogenesis regulators (such as VEGF, intratumor MVD), have also been shown to be potential predictors for HCC metastatic recurrence and clinical outcomes. One important new trend is to widely delineate biomarkers with genomic and proteomic expression with reference to predicting metastatic recurrence, molecular diagnosis, and classification, which has been drawing more attention recently. Body fluid (particularly blood and urine) testing for biomarkers is easily accessible and more useful in clinical patients. The prognostic significance of circulating DNA in plasma or serum and its genetic alterations is another important direction. More attention should be paid to these areas in the future. As understanding of tumor biology deepens, more and more new biomarkers with high sensitivity and specificity for HCC metastatic recurrence could be found and routinely used in clinical assays. However, the combination of the pathological features and some of the biomarkers mentioned above seems to be more practical up to now.

Decreased expression of KAI1 metastasis suppressor gene is a recurrence predictor in primary pTa and pT1 urothelial bladder carcinoma

OBJECTIVE

To examine the expression of the KAI1 metastasis suppressor gene and to evaluate its relationship with tumor recurrence in primary pTa and pT1 urothelial bladder carcinoma.

METHODS

Samples were obtained from 87 patients after transurethral resection (TUR). Tumor stage and grade were reviewed in 33 patients with pTa and in 54 patients with pT1, with a mean follow-up time of 47.4 +/- 30.1 months. The KAI1 protein immunohistochemical assay was performed. Prognosis was analyzed using the Kaplan-Meier method and Cox's proportional hazards model. Correlation between KAI1 expression and recurrence according to each clinicopathological factor was comparatively evaluated using the chi-squared test.

RESULTS

Decreased expression of KAI1 protein failed to reach statistical significance for stage (P = 0.25) or morphology of tumor stem (P = 0.19), but it was significantly related to tumor size (P = 0.016). The recurrence-free 5-year survival rates of the group with decreased KAI1 expression was 69.7%, which was significantly higher than the 22.2% for the KAI1-positive group (P < 0.0001). In univariate and multivariate analyses, decreased expression of KAI1 protein, stage pT1, tumor size >3 cm and sessile tumors were independent prognosis factors of recurrence. Despite the lower recurrence rate expected by considering only the clinicopathological factors, decreased KAI1 expression was able to identify the group with a high risk of recurrence.

CONCLUSIONS

Downregulated KAI1 expression in bladder tumors tends to relate to stage and morphology of the tumor stem and was significantly correlated to tumor size. Decreased expression of KAI1 was associated with the degree of invasiveness and progression of the cancer and was an independent prognostic factor of recurrence in primary pTa and pT1 urothelial bladder carcinoma.

Accelerated Induction of Bladder Cancer inPatchedHeterozygous Mutant Mice

The PATCHED (PTC) gene is recognized as a tumor suppressor in basal cell carcinoma. Mapping of a minimal region of deletion at 9q22.3 and observation of a decreased PTC expression in superficial papillary bladder tumors led us to hypothesize that it could also be involved in this cancer. To further investigate this hypothesis, we submitted Ptc(+/-) heterozygous mutant mice and their wild-type littermates to chemical carcinogenesis by adding N-butyl-N-(4-hydroxybutyl) nitrosamine to their drinking water. Preneoplastic and neoplastic changes were observed significantly earlier in the Ptc(+/-) than in the wild-type mice. Our data support the hypothesis of Ptc acting as a tumor suppressor gene in bladder cancer.

Genetic and epigenetic alterations of the blood group ABO gene in oral squamous cell carcinoma

Loss of histo-blood group A and B antigen expression is a frequent event in oral carcinomas and is associated with decreased activity of glycosyltransferases encoded by the ABO gene. We examined 30 oral squamous cell carcinomas for expression of A and B antigens and glycosyltransferases. We also examined DNA from these tumors for loss of heterozygosity (LOH) at markers surrounding the ABO locus at chromosome 9q34, for loss of specific ABO alleles, and for hypermethylation of the ABO promoters. Loss of A or B antigen expression was found in 21 of 25 tumors (84%) and was a consistent feature of tumors lacking expression of A/B glycosyltransferases. LOH at 9q34 was found in 7 of 27 cases (26%), and one case showed microsatellite instability. Among 20 AO/BO cases, 3 showed loss of the A/B allele and 3 showed loss of the O allele. Analysis of the proximal ABO promoter by methylation-specific PCR and melting curve analysis showed hypermethylation in 10 of 30 tumors (33.3%), which was associated with loss of A/B antigen expression. ABO promoter hypermethylation was also found in hyperplastic or dysplastic tissues adjacent to the tumors, suggesting that it is an early event in tumorigenesis. Collectively, we have identified molecular events that may account for loss of A/B antigen expression in 67% of oral squamous cell carcinomas.

[The PATCHED/Sonic Hedgehog signalling pathway in superficial bladder cancer]

Superficial bladder cancer shows a high frequency of total or partial chromosome 9 losses. Loss of heterozygosity at position 9q22.3 is one of the most frequent and is associated with highly recurrent tumours. The PATCHED gene, ortholog of a gene first described in the drosophila as a segment polarity gene, is located at 9q22.3. It is a member of a signal transduction pathway and a tumour suppressor gene (TSG), involved in basal cell carcinoma. We propose PATCHED as a TSG candidate in superficial bladder cancer.

Microsatellite Instability in Urothelial Carcinoma of the Upper Urinary Tract

PURPOSE

Transitional cell carcinoma (TCC) of the upper urinary tract (TCC-UUT) may develop with high frequency in patients with hereditary nonpolyposis colorectal cancer syndrome. Tumors in patients with this syndrome show genomic lesions in DNA mismatch repair genes that are detectable as microsatellite instability (MSI). Because little is known about genetic lesions in TCC-UUT compared with bladder TCC, we determined the genetic profiles (MSI and allelic loss) in a series of 26 upper urinary tract tumors using 5 informative microsatellite markers.

MATERIALS AND METHODS

A total of 26 paraffin embedded samples from 24 patients with clinically diagnosed TCC-UUT (renal pelvis and/or ureter) were tested for loss of heterozygosity (LOH) and MSI with the dinucleotide markers D9S171 (9p21) and D5S346 (5q22), and the mononucleotide repeats BAT25 (4q12), BAT26 (2p16) and BAT40 (1p13.1).

RESULTS

MSI was detected at 1 or more microsatellite loci in 12 of the 26 tumors (46%). The markers BAT40, BAT25, BAT26, D9S171 and D5S346 showed instability in 7, 4, 4, 2 and 3 tumor samples, respectively. LOH at D9S171 was detected in 58% of the cases and 10 of the 14 tumors showing LOH were superficial. LOH at D5S346 occurred in 27% of the cases and it was a feature of invasive high grade TCC-UUT.

CONCLUSIONS

Frequent LOH at D9S171 in TCC-UUT confirms that LOH at 9p21 is not only observed in bladder TCC, but rather in whole urinary tract TCC. Furthermore, our study indicates a high level of MSI in TCC-UUT, although it is a rare event in bladder cancer. The establishment of distinct genetic profiles between upper and lower urinary tract tumors could provide an additional tool to improve diagnosis, disease monitoring and prediction of prognosis.

Clinical significance of allelotype profiling for urothelial carcinoma

OBJECTIVES

To perform a global loss of heterozygosity (LOH) analysis on a cohort of urothelial carcinoma to investigate the clinical implication of specific chromosomal loss. Allelic deletions detected as LOH have been used to study the markers for carcinogenesis.

METHODS

We examined the allelic loss on 14 chromosomal regions in a total of 71 cases of urothelial carcinoma. The results were analyzed in relation to biologic indicators of urothelial carcinoma and the clinical outcome with a mean follow-up of 101 months.

RESULTS

The incidence of LOH in order of frequency was 9p (54.9%), 9q (49.3%), 13q (40.8%), 14q (40.8%), 10q (39.4%), 17p (39.4%), 8p (38.0%), 21q (36.6%), 11p (31.0%), 18q (23.9%), 4q (21.1%), 3p (16.9%), 6q (14.1%), and 1q (8.5%). Positive association with one of the indicators was observed in 3p, 9p, 9q, 10q, 14q, and 18q. The chromosomes that correlated with two biologic indicators were 4q, 6q, 11p, 17p, and 21q. Univariate analysis found that patients having combined 9p and 14q deleted tumors had particularly poor long-term survival compared with those with other patterns of chromosomal alterations (P = 0.01). In the multivariate model, nonpapillary tumors had a greater risk of recurrence, and stage classification was the only important indicator in predicting patient survival (P = 0.04).

CONCLUSIONS

LOH assessment does not provide independent prognostic value compared with stage classification. However, chromosomes 4q, 6q, 9p, 11p, 14q, 17p, and 21q may harbor important tumor suppressor genes involved in the progression of urothelial carcinogenesis.

[The role of tumor markers in prognosing transitional bladder cancer]

PURPOSE

Review the literature on tumor markers used for prognosis of transitional bladder cancer. The existing problems regarding grading and local staging of these tumors are also discussed.

METHODS

The published literature on transitional bladder cancer markers was identified using a Medline search and critically analysed.

RESULTS

There are significant interobserver differences in grading. There is a new grading system. There are also problems in local staging and low correlation between clinic stage and pathologic stage. Major tumor markers studied for prognosis of transitional bladder cancer are: flow cytometry, kariocytometric study, oncogenes (p53, bcl-2, Her2/Neu or c-erbB2), chromosomic alterations (chromosomes 9, 7 and 17), proliferation markers (Ki-67, MIB-1), cyclin-dependent kinases and its inhibitors (cyclin D1, cyclin E, p21Wafl, p27Kipl), vascular endothelial growth factor, other growth factors (fibroblastic, epidermal, hepatocyte, platelet-derived), metalloproteinases, cell adhesion molecules, and others.

CONCLUSIONS

At present, there are no prognostic markers for bladder cancer that are superior to conventional grading and staging, despite its imperfections. Standarization of assay methods in bladder tumor markers is needed to permit more conclusive and reproducible results and become a clinic tool. Controversy resulting from several studies make the meaning of some putative prognostic markers in transitional bladder cancer questionable.

Alteration of the PATCHED locus in superficial bladder cancer

Chromosome 9 alterations are the most frequently encountered cytologic anomalies in urothelial carcinoma (UC). We previously screened 139 low-stage UCs for loss of heterozygosity on chromosome 9, and identified five distinct regions likely to harbour tumour-suppressor genes. The present study focused on deletion mapping in the 9q22 region with 11 additional microsatellite markers. New deletions in the 9q22 region were found in five tumours. Deletion mapping allowed us to identify a 0.5 CM common minimal region of deletion between markers D9S280 and D9S1809, encompassing PATCHED (PTC), a gene identified as a tumour suppressor in basal cell carcinoma and in medulloblastoma. A marker located in the first intron of this gene showed the highest percentage of deletion (45%). cDNA sequencing in 15 tumours with deletion of PTC showed no mutation in the remaining allele. However, average expression of PTC mRNA measured by semiquantitative RT-PCR was significantly decreased in tumours with LOH in the 9q22 region, compared to normal urothelium (P=0.04), while it showed marked fluctuations in tumours without deletion. Our results suggest that the PTC gene is a putative suppressor at the 9q22 locus and that haploinsufficiency of this gene may be an early event in the development of papillary bladder tumours.

The prognostic molecular markers in hepatocellular carcinoma

The prognosis of hepatocellular carcinoma (HCC) still remains dismal, although many advances in its clinical study have been made. It is important for tumor control to identify the factors that predispose patients to death. With new discoveries in cancer biology, the pathological and biological prognostic factors of HCC have been studied quite extensively. Analyzing molecular markers (biomarkers) with prognostic significance is a complementary method. A large number of molecular factors have been shown to associate with the invasiveness of HCC, and have potential prognostic significance. One important aspect is the analysis of molecular markers for the cellular malignancy phenotype. These include alterations in DNA ploidy, cellular proliferation markers (PCNA, Ki-67, Mcm2, MIB1, MIA, and CSE1L/CAS protein), nuclear morphology, the p53 gene and its related molecule MD M2, other cell cycle regulators (cyclin A, cyclin D, cyclin E, cdc2, p27, p73), oncogenes and their receptors (such as ras, c-myc, c-fms, HGF, c-met, and erb-B receptor family members), apoptosis related factors (Fas and FasL), as well as telomerase activity. Another important aspect is the analysis of molecular markers involved in the process of cancer invasion and metastasis. Adhesion molecules (E-cadherin, catenins, serum intercellular adhesion molecule-1, CD44 variants), proteinases involved in the degradation of extracellular matrix (MMP-2, MMP-9, uPA, uPAR, PAI), as well as other molecules have been regarded as biomarkers for the malignant phenotype of HCC, and are related to prognosis and therapeutic outcomes. Tumor angiogenesis is critical to both the growth and metastasis of cancers including HCC, and has drawn much attention in recent years. Many angiogenesis-related markers, such as vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), platelet-derived endothelial cell growth factor (PD-ECGF), thrombospondin (TSP), angiogenin, pleiotrophin, and endostatin (ES) levels, as well as intratumor microvessel density (MVD) have been evaluated and found to be of prognostic significance. Body fluid (particularly blood and urinary) testing for biomarkers is easily accessible and useful in clinical patients. The prognostic significance of circulating DNA in plasma or serum, and its genetic alterations in HCC are other important trends. More attention should be paid to these two areas in future. As the progress of the human genome project advances, so does a clearer understanding of tumor biology, and more and more new prognostic markers with high sensitivity and specificity will be found and used in clinical assays. However, the combination of some items, i.e., the pathological features and some biomarkers mentioned above, seems to be more practical for now.

Identification and characterization of Nek6 protein kinase, a potential human homolog of NIMA histone H3 kinase

In Aspergillus nidulans, the kinase activity of NIMA (never in mitosis, gene A) is critical for the initiation of mitosis. NIMA regulates mitotic chromatin condensation through phosphorylation of histone H3 at serine 10. In the present study, we identified human Nek6 (hNek6), a member of the mammalian NIMA-related kinases. The predicted hNek6 protein is comprised of 338 amino acids. Northern blot analysis revealed that hNek6 transcripts are ubiquitously expressed with the highest expression found in the heart and skeletal muscle. Lower cell cycle-dependent expression of hNek6 transcripts was observed in the early G1 phase. GFP-fused hNek6 protein showed both nuclear and cytoplasmic localizations in HeLa cells. Fluorescence in situ hybridization using full-length hNek6 cDNA as a probe showed that the hNek6 gene is localized to human chromosome 9q33-34, a region at which the loss of heterozygosity is associated with transitional cell carcinomas. Importantly, recombinant hNek6 protein produced in insect cells effectively phosphorylated histones H1 and H3, but not casein. Thus, these results suggest that, unlike other mammalian NIMA-related kinases, Nek6 is a mitotic histone kinase which regulates chromatin condensation in mammalian cells.

Destabilization of chromosome 9 in transitional cell carcinoma of the urinary bladder

The most frequent genetic alteration in transitional cell carcinoma of the urinary bladder (TCC) is loss of chromosome 9 which targets CDKN2A on 9p. The targets on 9q are not confirmed. Here, 81 advanced TCC specimens were investigated for loss of heterozygosity (LOH) and homozygous deletions (HD) on chromosome 9q using multiplex analysis of microsatellite markers. 41/81 tumours (51%) showed LOH on 9q, with LOH at all markers in 33 cases. Eight partial losses involved three regions in 9q12, 9q22.3, and 9q33- 9q34. No mutations were identified in the candidate tumour suppressor gene DBCCR1 in three tumours showing restricted LOH at 9q32-33. 22% of the specimens had HD at CDKN2A, but no HD was found on 9q. Two tumours had lost 9p only and five 9q only. 9q LOH was not related to tumour grade or stage and present or absent with equal frequency in recurrent TCC. LOH on 9q correlated with the extent of genome-wide hypomethylation (P < 0.0001) which extended into satellite sequences located in 9q12 juxtacentromeric heterochromatin. While the high frequency of chromosome 9q loss in TCC may reflect destabilization of the chromosome related to hypomethylation of repetitive DNA, the data are compatible with the existence of tumour suppressor genes on this chromosome arm.

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.