The micronucleus assay in human exfoliated urothelial cells: application in a genotoxicity study of workers exposed to a mineral jelly containing sodium nitrite and N-phenyl-1-naphthylamine

Exposure to certain chemical agents in occupational settings has been identified as carcinogenic to the human bladder. Micronucleus (MN) analysis in exfoliated urothelial cells is an interesting method for biomonitoring genetic damage in human populations. However, few studies have been performed in an occupational context. The aim of this study was to examine whether the occupational use of a mineral jelly induced a genotoxic risk for workers employed at a single factory producing bearings using the MN test on exfoliated urothelial cells. The prevalence of micronucleated exfoliated urothelial cells (MNC) was determined in 35 female workers with dermal exposure to the jelly and 41 female controls. The mean percentage of MNC (expressed as percent cells with MN per 1000 cells scored) observed in the exposed worker group was 0.46 +/- 0.11% (range 0-2.8) and in the control group 0.14 +/- 0.03% (range 0-0.8). There is a significant job effect (P = 0.0018, MANCOVA) on the prevalence of MNC, whereas age and smoking habit had no significant effect (P = 0.90 and 0.91, respectively). There is no interaction between job and smoking habit (P = 0.4421). Exposure to the mineral jelly appeared to be the main factor inducing the increased prevalence of MNC. This may be due to the presence of mutagens/carcinogens in the jelly: an aromatic amine, N-phenyl-1-naphthylamine (CAS no. 90-30-2), which is carcinogenic in mice, or sodium nitrite (CAS no. 7632-00-0), which is genotoxic in human cell systems. In conclusion, these results suggest that use of the mineral jelly could present a genotoxic risk for workers. We think that the MN assay on exfoliated cells could be valuable for biological monitoring purposes in occupational contexts as a marker of significant exposure to bladder mutagenic/carcinogenic agents.     

Influence of genetic polymorphisms on biomarkers of exposure and genotoxic effects in styrene-exposed workers

A study on 44 workers exposed to styrene and 44 matched referents was performed in order to examine the influence of genetic polymorphisms in biotransformation and DNA repair enzymes on the levels of N-terminal hemoglobin adducts and genotoxicity biomarkers. Urinary mandelic acid concentration averaged 201.57 mg/g creatinine +/-148.32 in exposed workers, corresponding to a calculated average airborne styrene exposure of 9.5 ppm +/-9.6. Individuals with a high level of N-terminal valine adducts had higher levels of DNA damage, as evaluated by the Comet assay (r = 0.29, P = 0.008). Frequencies of micronucleated mononucleated lymphocytes (MNMC) (0.71 +/- 0.88 vs 0.11 +/- 0.20, P<0.0001), micronucleated binucleated lymphocytes (MNBC) (3.93 +/- 2.75 vs 2.65 +/- 1.94, p = 0.02) and micronucleated nasal epithelial cells (0.52 +/- 0.49 vs 0.23 +/- 0.31, p = 0.04) differed significantly between the exposed and referent groups. In the whole group of 88 individuals, higher frequencies of MNMC were found in individuals possessing the XRCC3 Met(241) allele and those individuals with the XRCC1 Gln( (399) ) allele showed higher frequencies of MNMC and MNCB. In vitro DNA repair capacity, as measured by residual DNA strand breaks in peripheral blood leukocytes after a styrene oxide challenge, was also influenced by styrene exposure, with an apparent induction of early repair mechanisms associated with the intensity of recent exposure and a reduction of late (24 h) repair capacity that was associated with the duration of employment. After 1 h of repair, lower levels of residual DNA damage were found in individuals possessing GSTT1 (P = 0.043). After 24 h of repair, lower residual DNA damage was found in individuals homozygous for XRCC1 Arg(194) (P = 0.013). Multivariate regression analysis indicated that the duration of exposure, smoking habits and polymorphisms of XRCC1 at codon 399 were important variables affecting the genotoxic responses. Our data suggest that DNA damage is formed in workers exposed to low concentrations of styrene, and that genotypes of metabolising and DNA-repair genes are important for the assessment of individual genotoxic risk to styrene. The in vitro DNA repair phenotype assay might be a valuable method to estimate the susceptibility of workers.     

Hypochromatic large urothelial cells in urine cytology are indicative of high grade urothelial carcinoma

In this study, we have examined 67 cytology specimens from patients from 2014 to 2016. The ratio man to women was 4:1 with a median age of 75 years (range: 55–87 years). Thin‐Prep processed urinary cytology specimens demonstrated large urothelial cells, with cytologic features of malignancy, thus including hypochromatic nuclei with occasional peripherally accentuated chromatin rim. The cytological diagnosis of High Grade Urothelial Carcinoma (HGUC) was made in 55 patients while 12 specimens were classified as Atypical Urothelial Cells (AUC). This cases represent the 15% of the HGUC and the 4% of the AUC cases diagnosed in our department between 2016 to 2018. Of note, is the fact that in AUC cases, hypochromatic irregular urothelial cells were the only type of cells with malignant features observed in the specimen, and therefore, according to the Paris System criteria, the absence of nuclear hyperchromasia precludes a diagnosis of suspicious high grade urothelial carcinoma (SHGUC) or High Grade Urothelial Carcinoma (HGUC). Subsequent biopsy diagnosis of high grade urothelial carcinoma confirmed the cytological diagnosis of HGUC in 55 patients but also in all 12 patients with a AUC cytologic diagnosis. Our study series support the hypothesis that malignant urothelial cells with hypochromatic nuclei seen in urine cytologic specimens can be diagnostic for HGUC based on their very large nuclei, high nuclear cytoplasmatic ratio (N/C) >0.7, irregular nuclear outlines and coarse (frequently peripheral) chromatin in the absence of hyperchromasia.     

Hereditary nonpolyposis colorectal cancer syndrome in a patient with urothelial carcinoma of the upper urothelial tract

Urothelial carcinoma of the upper urinary tract is relatively uncommon but may develop as a manifestation of the hereditary nonpolyposis colorectal cancer syndrome (HNPCC), which is characterized by mutations in a number of DNA mismatch repair genes and detectable as microsatellite instability or loss of the respective protein by immunostaining. No well-established screening test is available for urothelial carcinomas of the upper urinary tract, and little is known of the clinical impact of screening for HNPCC in patients with upper urinary tract cancer. We describe herein a patient with a urothelial carcinoma of the ureter and a strongly positive history of cancer, who was subsequently found to have HNPCC. Our findings reinforce the importance of obtaining a comprehensive history of cancer in patients with urothelial carcinoma of the renal pelvis and ureter. Subsequent identification of individuals with HNPCC enables the patient and at-risk relatives to benefit from targeted surveillance and management programs.     

Upper tract urothelial carcinoma: a clinicopathologic study including microsatellite instability analysis.

Urothelial carcinoma of the renal pelvis and ureter may develop as a manifestation of the hereditary nonpolyposis colorectal cancer syndrome that is characterized by mutations in a number of DNA mismatch repair genes and detectable as microsatellite instability. In this study, we examined microsatellite instability and the clinicopathologic features of urothelial carcinoma of the renal pelvis (n = 61) and ureter (n = 53) from 114 consecutive patients surgically treated from 1985-1992. Clinical data were obtained through chart review. Matched normal and tumor DNA was extracted from paraffin-embedded tissue, and a panel of six microsatellite loci was analyzed. The male-female ratio was 2.8:1 with a median age of 70 years (range, 28 to 92 y). Microsatellite analysis was successful in 67 tumors, and 21 (31.3%) patients had tumors that exhibited microsatellite instability. Patients with microsatellite-unstable tumors were significantly more likely to have additional nonurologic cancers (P =.015) including colorectal carcinoma (P =.001) compared with patients with tumors that did not exhibit microsatellite instability. In addition, patients with microsatellite-unstable tumors showed more colorectal cancers in their family (P =.026) and were more likely to have higher grade urothelial carcinoma of the upper tract (P =.028). Grade and stage, but not microsatellite status, were the strongest predictors of cancer-specific survival. This study found the highest frequency of microsatellite instability in upper urothelial tract carcinomas reported to date and highlights upper tract urothelial carcinoma as a marker of the hereditary nonpolyposis colorectal cancer syndrome in some patients. These findings reinforce the importance of obtaining cancer histories in patients with upper tract urothelial carcinoma to subsequently identify individuals with the hereditary nonpolyposis colorectal cancer syndrome and at-risk relatives for surveillance and management programs.     

The clinical efficacy of Bladder Chek NMP22 in urothelial cancer

The purpose of this study is to investigate the clinical efficacy of a quick test for NMP22 (Nuclear Matrix Protein 22), Bladder Chek NMP22, as a screening test for urothelial cancers. The subjects include 51 cases(43 cases with pathologically confirmed bladder cancer, and 8 cases with upper urothelial cancer). Bladder Chek NMP22 revealed false positive in the urine with more than 1 x 10(5)/microliter of erythrocytes and 1 x 10(3)/microliter of white blood cells. Thus, showing that Bladder Chek NMP22 was not relatively affected by the contaminated erythrocytes and white blood cells, compared with other conventional methods to detect urinary malignant disease. In 51 cases diagnosed of having pathologically urothelial cancers, the sensitivity of Bladder Chek NMP22 was 56.8%. Bladder Chek NMP22 demonstrated more excellent sensitivity than the other methods. The positivity of Grade3 patients was 68.4%, 68.4% and 63.2% by Bladder Chek NMP22, NMP22 ELISA and urinary cytology. In contrast, the positivity rate for the patients with Grade1 stage was 58.3%, 33.3% and 8.3%. There is no significance of positivity rate between each examination in patients with high grade cancer. However Bladder Chek NMP22 demonstrated the higher positivity in patients with low grade cancer. Bladder Chek NMP22 test could be an easy and confidential method to detect urothelial cancers, especially with low grade, as a screening examination.     

Fluorescence in situ hybridization study of chromosome abnormalities of upper urinary tract urothelial carcinoma in paraffin-embedded tissue

Urothelial carcinomas arising from the upper urinary tract (renal pelvis and ureter) are rare and few molecular genetic studies of these tumors have been conducted to date. We investigated hyperploidy at chromosomes 3, 7, and 17 using a multitarget fluorescence in situ hybridization system to identify genetic alterations in patients with urothelial carcinomas of the upper urinary tract. Chromosomal aberrations are seen most frequently in the high-grade tumors. A highly significant relationship was found between an increase in the percentage of hyperdiploidy and high grade for each chromosome (chromosome 3, P = 6 × 10(-4); chromosome 7, P = 2 × 10(-4); chromosome 17, P = 6 × 10(-5)). To determine whether these associations were independent for each chromosome, the correlation between percentage of hyperdiploidy for each pair of chromosomes was examined. In each case, the correlation was highly significant (R = 0.89-0.91). No statistically significant association was found between percentage of hyperdiploidy and tumor stage for any chromosome.     

Small cell carcinoma of urinary bladder is differentiated from urothelial carcinoma by chromogranin expression, absence of CD44 variant 6 expression, a unique pattern of cytokeratin expression, and more intense γ-enolase expression

AIMS: Small cell (neuroendocrine) carcinoma of the urinary bladder is clinically more aggressive than urothelial (transitional cell) carcinoma. We have investigated the immunohistochemical markers most useful in diagnosing small cell carcinoma in bladder. METHODS AND RESULTS: We evaluated the expression of chromogranin A, CD44 variant 6 (CD44v6), cytokeratin (CAM 5.2), gamma-enolase, synaptophysin, and CD45 in 46 small cell carcinomas of the bladder. Small cell and urothelial carcinoma were mixed in 21 (46%) cases. The two immunohistochemical markers with best ability to discriminate between small cell and urothelial carcinoma were chromogranin A and CD44v6. Chromogranin A had 97% specificity for small cell carcinoma, staining 65% of cases with 2+/3+ mean intensity; only one case (5%) of urothelial carcinoma was weakly (1+/3+) positive. CD44v6 was 80% specific for urothelial carcinoma, with immunoreactivity in 60% of cases, compared with 7% of small cell carcinoma cases. In cases positive for CD44v6, the mean percentage of reactive urothelial carcinoma cells was 75% (range 10-100%), greater than the 12% of cells in three cases of small cell carcinoma (P = 0.31); further, the pattern of immunoreactivity was membranous vs. focal cytoplasmic, respectively. All small cell carcinomas stained with one of the three neuroendocrine markers tested; 76% of cases were reactive for synaptophysin and 93% for gamma-enolase, with specificities of 86% and 73% in comparison to urothelial carcinoma. gamma-enolase staining of small cell carcinoma was more intense (P = 0.01) than for urothelial carcinoma. Cytokeratin CAM 5.2 stained a mean 47% of cells in small cell carcinoma, always in a punctate perinuclear pattern, and 75% in urothelial carcinoma, in a membranous pattern. CONCLUSIONS: CD44v6, chromogranin A, and possibly gamma-enolase and cytokeratin (CAM 5.2) help differentiate small cell carcinoma from urothelial carcinoma.     

Primary urothelial carcinoma of the upper tract: Important clinicopathological factors predicting bladder recurrence after surgical resection

The aim of the present study was to further characterize potential clinicopathological predictors for urinary bladder recurrence-free survival (UBRFS) in patients with primary urothelial carcinoma of the upper urinary tract (UUT-UC). The present series included 385 cases of surgically treated primary localized UUT-UC without previous or concurrent urothelial carcinoma of the urinary bladder. Among the 374 patients with follow-up information, clinicopathological features and therapeutic information including whether they received a laparoscopy-assisted nephroureterectomy (LNU) and adjuvant chemotherapy were correlated with UBRFS. After a median follow up of 69 months, 86 patients (23%) developed urinary bladder recurrence. The median time to develop urinary bladder recurrence was 12 months. At the univariate level, an increment in histological grade ( P = 0.0321), a prominent papillary configuration ( P = 0.0004), LNU ( P = 0.0397) and male gender ( P = 0.0401) significantly predicted an inferior UBRFS. At the multivariate level, increase of histological grade ( P < 0.0001, relative risk (RR) = 3.776), prominent papillary configuration ( P < 0.0001, RR = 3.244), and male gender ( P = 0.0463, RR = 1.444) independently predicted UBRFS. In conclusion, male patients and those with high-grade and papillary UUT-UC, and who received LNU had higher risks of urinary bladder recurrence. Accordingly, for these patients, more intensive follow up coupled with postoperative intravesical adjuvant therapy to prevent urinary bladder recurrence should also be considered.     

Invasive urothelial carcinoma with chordoid features of the ureter: a rare entity and review of literature

Invasive urothelial carcinoma (UC) is characterized by some histologic variants that can sometimes lead to diagnostic difficulty. In addition to those described by the World Health Organization. Recently invasive urothelial carcinoma with chordoid features (UCC) has been described as a distinct entity and there are relatively few reported cases in the English-language literature. To date 13 cases of UCC have been reported in 2 case series, respectively in 2009 and 2015. We report the 14^th case in an 80-year-old female, and to the best of our knowledge this is the second case report of UCC in the ureter. She was admitted to our hospital with macroscopic haematuria and unspecific left lower abdominal pain. Computed tomography scan revealed a soft tissue nodule in the middle of the left ureter. The left nephroureterectomy was performed. Morphologically, 85% areas had acellular myxoid stroma was associated with the neoplastic cells. The neoplastic cells had scant eosinophilic cytoplasm and were arranged into cords closely mimicking chordoma or extraskeletal myxoid chondrosarcoma. 15% areas was typical invasive urothelial carcinoma, and focal areas had transition phenomenon between them. Immunohistochemically, the tumor cells were positive for CK, 34βE12 and p63, but were negative for S100, AFP, CD34, Syn and CgA. The final histopathological diagnosis was UCC of the ureter.     

Evidence of exposure to aristolochic acid in patients with urothelial cancer from a Balkan endemic nephropathy region of Romania

Recently, chronic Aristolochia poisoning was found responsible for the aetiology of Balkan endemic nephropathy (BEN) in Croatia, Serbia, and Bosnia, and diet was the likely route of exposure to aristolochic acid (AA). BEN, often associated with an increased incidence of upper urinary tract carcinoma (UUC), also affects residents of certain rural villages in Romania. AA is a nephrotoxin and human carcinogen that forms DNA adducts after metabolic activation, which induce characteristic TP53 mutations in urothelial tumours. Here we present the first evidence linking AA exposure to UUC in residents of an endemic region in the Romanian Mehedinti County. DNA was extracted from kidney and tumour tissue of seven patients who underwent nephroureterectomy for UUC and resided in BEN villages (endemic group). Five patients with UUC from nonendemic villages served as controls. AA‐DNA adducts (7‐(deoxyadenosin‐N⁶‐yl)‐aristolactam I), established biomarkers of AA exposure, were identified by ³²P‐postlabelling in renal DNA of six patients from the endemic group and in one of the nonendemic group (adduct levels ranged from 0.3 to 6.5 adducts per 10⁸ nucleotides). Additionally, an A to T transversion in TP53, a base substitution characteristic of AA mutagenic activity was found in urothelial tumour DNA of one patient from the endemic group. Our results provide a molecular link to the cause of urothelial tumours in BEN regions of Romania indicating that AA is the common aetiological agent for BEN across its numerous geographical foci. Environ. Mol. Mutagen., 2012. © 2012 Wiley Periodicals, Inc.     

Muscle prelamination with urothelial cell cultures via fibrin glue in rats

The purpose of the study was to transplant autologous cultured urothelial cells onto a muscle via fibrin glue as a delivery vehicle to create a vascularized, living matrix lined with urothelium that could subsequently be used for urinary reconstruction. Bladder tissue specimens from male Wistar rats (n = 32; 350--500 g) were harvested for urothelial tissue culture. After 8--10 days when the primary cultures became confluent, the cultured urothelial cells were injected underneath the rectus sheath onto the rectus muscle. As delivery vehicle we compared standard culture media and fibrin glue. At 1- and 4-week intervals following urothelial cell grafting, sections of the muscle were analyzed for urothelial graft take using Hematoxylin & Eosin and immunohistochemical staining. The histology demonstrated viable, multilayered clusters of urothelium cells on the muscle surface only in the group using the fibrin glue delivery vehicle. We conclude that a muscle can be successfully prelaminated with autologously cultured urothelial cells via fibrin glue and has therefore potential for urinary reconstructions.     

Micronucleus in atypical urothelial cells

The objective of this study is to evaluate the role of micronuclei (MN) in identifying the atypical urothelial cells urinary cytology. This is a retrospective study of a total of 30 cases of urine samples. Of these, 15 cases were selected where the initial diagnosis was atypical urothelial cell and later turned out as malignant cells on follow‐up histopathology. The rest of the 15 cases were reported as normal urothelial cells. The number of MN in 1,000 urothelial cells was counted in all the cases and was expressed as percentage. All the cases diagnosed as atypical urothelial cells show the presence of MN. The mean number of MN was 2.53 ± 0.99%. No MN was noted in any of the normal urothelial cells in control cases. The Student's t‐test of MN scoring was highly significant (P < 0.000) in test (atypical urothelial cells) versus control group (benign urothelial cells). MN is an important biomarker of malignancy. Micronuclear score in atypical urothelial cells in urine cytology smears may help in proper diagnosis of the case. Diagn. Cytopathol. 2010;38:811‐813. © 2010 Wiley‐Liss, Inc.     

Silver-stained nucleolar organizer proteins in urothelial bladder lesions. A morphometric study.

The diagnostic value of image analysis of silver-stained nucleolar organizer regions (AgNORs) has been investigated in 170 urothelial bladder lesions obtained by transurethral biopsies in the same number of patients. According to the WHO classification 25 specimens showed a flat non-invasive growth pattern with simple hyperplasia or mild dysplasia (H/D1 = 10), as well as moderate (D2 = 10) to severe atypia (Cis = 5). 135 samples were of papillary and/or infiltrating type including polypoid cystitis (pC = 5), true papillomas (G0 = 7), and carcinomas of different malignancy grade (G1 = 30, G2 = 55, G3 = 38). 10 biopsies served as normal controls. Benign non-neoplastic urothelium (controls, H/D1, pC) exhibited few but large AgNORs (mean number [MNN] = 3.3 +/- 0.5, mean area [MNA] = 0.29 +/- 0.08 micron 2), whereas carcinomatous lesions (Cis, G1-G3) showed numerous small silver-stained dots within their nuclei (MNN = 6.9 +/- 1.1; MNA = 0.12 +/- 0.04 micron 2). Both parameters, MNN and MNA, were inversely correlated (r = -0.69, p less than 0.001); their quotient (NQ = MNN/MNA) revealed a clear cut difference in the AgNOR content of benign (control, H/D1:NQ = 12.8 +/- 2.5) and moderate to severe atypical flat urothelial lesions (D2, Cis: NQ = 44.2 +/- 12.8, p less than 0.001). This parameter also discriminated between G1 (NQ = 40.7 +/- 17.3), G2 (NQ = 57.5 +/- 18.8), and G3 carcinomas (NQ = 79.0 +/- 21.8, p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)     

Evidence for the early onset of aberrant promoter methylation in urothelial carcinoma

There is evidence that carcinoma in situ (CIS) is the precursor of invasive urothelial carcinoma, a tumour characterized by frequent gene promoter methylation. The timing of altered DNA methylation is unknown in this pathway. Here we investigate gene methylation in 196 consecutive samples of normal urothelium, CIS, and tumours from 104 patients with both CIS and invasive urothelial carcinoma using quantitative methyl-sensitive polymerase chain reaction for six genes (p16, p14, E-cadherin, RARbeta2, RASSF1a, and GSTP1). Control normal urothelial samples from 15 patients with no history of urothelial carcinoma were also analysed. Immunohistochemistry established the expression of well-characterized CIS markers p53 and cytokeratin 20. Promoter methylation occurred frequently in both normal urothelium and CIS samples from patients with urothelial carcinoma, and increased with progression from normal to invasive urothelial carcinoma, at both specific loci (chi2 test: E-cadherin, p=0.0001; RASSF1a, p=0.003, RARbeta2, p=0.007, p16, p=0.024) and in general (methylation indices [t-test, p<0.0001]). Methylation was associated with cytokeratin 20 expression (t-test, p=0.004) and poor prognosis, and with increased progression to tumour death in patients whose CIS samples showed methylation, in comparison with those without methylation (log rank p<0.03). Promoter methylation occurs early in the urothelial carcinogenic pathway and appears to be a good biomarker of the invasive urothelial carcinoma phenotype.     

DNA damage in lymphocytes of rural Indian women exposed to biomass fuel smoke as assessed by the Comet assay

The Comet assay has found wide acceptance in monitoring human genotoxicity caused by lifestyle and occupational and environmental factors. In the present study, we have used the Comet assay to measure the DNA damage in a population of rural Indian women cooking with biomass fuels (BMFs; fire wood and cow dung cakes). Out of 144 volunteers, 70 used BMFs for domestic cooking, while the remaining 74 used liquefied petroleum gas (LPG) and served as a reference population. All the individuals had comparable socioeconomic backgrounds and were between 20 and 55 years of age. Significantly higher levels of DNA damage were observed for BMF users than for LPG users. For BMF users in comparison with the reference population, Olive tail moment was 3.83 +/- 0.15 (arbitrary units) vs. 2.77 +/- 0.07 (P < 0.001); % tail DNA was 11.19 +/- 0.35 vs. 8.29 +/- 0.20 (P < 0.001); and comet tail length (microm) was 51.15 +/- 1.37 vs. 40.26 +/- 0.88 (P < 0.001). Similar significant differences were found when the groups were stratified by age and length of exposure. This study suggests that exposure to BMF smoke leads to greater levels of DNA damage than exposure to LPG combustion products.     

Papillary urothelial neoplasm of low malignant potential of the urinary bladder: clinicopathologic and outcome analysis from a single academic center

Few long-term single-center studies have addressed the outcome of patients with papillary urothelial neoplasms of low malignant potential. Our study evaluates the behavior of these tumors occurring as primary urinary bladder lesions. For this purpose, 34 primary in-house cases diagnosed and treated between 1998 and 2008 were identified from our medical records. Upon review, 3 cases were upgraded to noninvasive low-grade urothelial carcinomas and excluded from further evaluation. During follow-up (range, 3-108 months; mean, 42 months), 13 patients developed recurrences; and 9 patients progressed to a noninvasive higher grade lesion (8 to low-grade and 1 to high-grade urothelial carcinomas). None of our patients developed stage progression (>pTa) or died of bladder cancer. Size of the primary tumor was associated with the risk of recurrence (P = .043), whereas the number of episodes of recurrence was associated with the likelihood of grade progression (P = .034). In conclusion, recurrences were observed in 42% of all our patients, with a grade progression rate of 29%. None of our patients developed invasive carcinoma or died as a consequence of their disease. Considering the low but definitive risk of recurrence and grade progression, appropriate clinical follow-up of patients with primary papillary urothelial neoplasm of low malignant potential is warranted.     

E-cadherin expression in invasive urothelial carcinoma

E-cadherin (E-CD) is a transmembrane glycoprotein involved in intercellular adhesion. A loss or reduction in E-CD expression has been linked to the invasive phenotype of a wide variety of human neoplasms, including bladder tumors. The objective of this study was to compare the E-CD expression at different depths of tumor invasion below the bladder's basement membrane in high- and low-grade urothelial carcinomas to investigate whether deeper tumor invasion and higher-grade invasive urothelial carcinomas are associated with decreased E-CD expression. E-cadherin staining was performed on 29 formalin-fixed, paraffin-embedded sections from high- and low-grade urothelial carcinoma specimens using an automatic immunohistochemical stainer. The sections were divided into three categories according to the depth of invasion below the basement membrane: upper, middle, and lower. The percentage and intensity of E-CD cell membrane staining for the three categories were calculated using a quantitative automated cellular imaging system. The percentage of cells that stained for E-CD was 82.6% +/- 1.4% (mean +/- SD) in the upper layer, 59.6% +/- 2.2% in the middle layer, and 29.4% +/- 2.7% in the lower layer. The intensity of E-CD expression was 64.7 +/- 3.2 units in the upper layer, 43.3 +/- 2.9 units in the middle layer, and 26.1 +/- 3.1 units in the lower layer. There were significant differences between the three layers in both the percentage and intensity of cellular E-CD staining (P<.05). Normal urothelium, high-grade urothelial dysplasia/carcinoma in situ, and superficial noninvasive papillary urothelial carcinoma maintained E-CD expression. However, once malignant cells infiltrated through the basement membrane, E-CD expression decreased. The more poorly differentiated urothelial carcinoma, the deeper the nests, and the smaller the clusters of neoplastic cells within the tumor were, and the more decrease in E-CD expression noted. The degree of decreased E-CD expression was directly proportional to the degree of tumor differentiation and depth of infiltration in invasive urothelial carcinoma. Down-regulation of E-CD may be one of the pathways responsible for tumor differentiation and may promote deeper invasion in urothelial carcinomas.