Protein networking in bladder cancer: immunoreactivity for FGFR3, EGFR, ERBB2, KAI1, PTEN, and RAS in normal and malignant urothelium

A panel of markers, selected for the suspected bladder cancer relevance of their corresponding genes, were explored for their expression and subcellular location in urinary bladder tissue. The expression in normal urothelium, in non-metastasised transitional cell carcinomas (TCC), and in primary metastasised TCC with corresponding metastases was mapped. Potential associations between the proteins were identified. The observations were then combined in a set of hypotheses aimed at further hypothesis testing. Membranous ERBB4 and cytoplasmic p21RAS were downregulated in carcinoma cells compared with normal urothelium cells. FGFR3 was translocated from the cytoplasm to the nucleus. ERBB2 was translocated to the membrane and seemingly upregulated in one subgroup and conversely downregulated in another. EGFR, KAI1 and possibly PTEN revealed increased membranous immunoreactivity in non-metastasised tumours. The metastases showed decreased nuclear FGFR3 and membranous PTEN staining compared with corresponding primary tumours. EGFR expression was positively correlated with the expression of PTEN and FGFR3. The expression of ERBB2 was negatively correlated with p21RAS expression. According to our results, bladder carcinogenesis comprises FGFR3 translocation to the nucleus, upregulation of EGFR, ERBB2, KAI1 and PTEN; downregulation of p21RAS; and translocation of EGFR, ERBB2, and possibly PTEN to the membrane. Our results support the hypotheses regarding PTEN and KAI1 functioning as tumour suppressors in bladder cancer. EGFR and KAI1 may discriminate between non-metastasised and metastasised cancers. A complex network of associations between the factors is suggested.

The urothelium in overactive bladder: passive bystander or active participant?

The urothelium was once purported to be a passive membrane. However, a growing body of evidence indicates that the urothelium actively participates in sensory functions, expressing various receptors and ion channels, as well as releasing neurotransmitters in response to stimuli. Vanilloid receptors, P2X3 purinergic receptors, adenosine triphosphate, nitric oxide, and acetylcholine have been implicated in urothelial-neuronal interactions. Substances released from urothelial cells can alter the excitability of bladder afferent nerves acutely and chronically; these observations appear to be of particular importance in chronic bladder conditions and in the aging bladder. Evidence suggests that the involvement of the muscarinic receptor in bladder function extends beyond detrusor contractility and into afferent sensory functioning. These observations have significant implications for a more complete understanding of the effects of currently used drugs on these sensory mechanisms and for identifying potential targets for pharmacologic intervention in bladder disorders.

Profiles of the 2 INK4a gene products, p16 and p14ARF, in human reference urothelium and bladder carcinomas, according to pRb and p53 protein status

The INK4a/ARF locus encodes 2 cell cycle regulatory proteins: p16 and p14(ARF). P16 inhibits the activities of cdks, which maintain the retinoblastoma protein (pRb) in its active hypophosphorylated state. P14(ARF) blocks MDM2-induced p53 degradation and transactivational silencing. In this study, we investigated the expression of p16 and p14(ARF) in reference human urothelium and in 51 urothelial carcinomas (UCs) of all stages and grades, by reverse transcription-polymerase chain reaction (RT-PCR). Patterns of p14(ARF) and p16 expression were compared with each other and then with patterns of p53 and pRb protein expression, respectively, as determined by immunohistochemistry. P14(ARF) and p16 mRNAs were present at low levels or were undetectable in reference urothelia and in most superficial tumors, whereas they were present at high levels in a subset of tumors of advanced stage and high grade. The expression profiles of these 2 mRNAs were correlated in all but 4 cases, indicating that the 2 INK4a products may have nonredundant functions. Forty-six of the 51 tumors (90%) presented changes to or a lack of activation of the p14(ARF)-p53 pathway and were p53 positive (n = 10), p14(ARF) negative (n = 23), or both p53 positive and p14(ARF) negative (n = 13), suggesting that these 2 components of the pathway may be altered or nonactivated. Markedly high levels of p16 mRNA (n = 5) were associated with the absence of pRb expression, with the exception of 1 case in which the p16 gene contained a deletion mutation. A lack of p16 mRNA or low levels of this mRNA were associated with pRb detection in all but 1 case. In invasive UCs, the p16-pRb pathway, the p14(ARF)-p53 pathway, or in many cases both pathways were altered or not activated, demonstrating the involvement of these pathways in invasive bladder tumorigenesis.

[The relationship between uretero-cloacal structure in birds and sigmoidorectal pouch surgery]

PURPOSE

The present study was planned to investigate morphological, functional and histological properties of the natural ureterocloacal for in birds as well as to provide an appropriate information which may contribute to rectosigmoidal pouch surgery and to decrease its complications.

MATERIALS AND METHODS

Thirty chickens (Gallus domesticus, 26 broilers, 4 layers) with a mean weight of 1870 +/- 88 g were used for this study. Histological and morphological evaluation of the cloaca was performed. Urethral reflux was estimated using X-rays.

RESULTS

We found that the cloaca had three parts from cranial to caudal: coprodeum, urodeum and proctodeum respectively. A coprourodeal fold (CUF) between the coprodeum and urodeum and a uroproctodeal fold between the urodeum and proctodeum were detected. Settling of the muscle clusters both in the ureter and urodeum near the opening area appeared to be a strong sphincter structure and the ureters are opened to a structure covered by a transitional epithelium, which is similar to bladder in humans (connecting two identical epithelia). According to X-rays following the administration of a radio-opaque substance, there was no ureteral reflux in any of them.

CONCLUSIONS

The natural urointestinal structure in birds has a spontaneous ureterointestinal anti-reflux opening. The coprourodeal fold that prevents the mixing of faeces and urine, inhibits the effects of increased pressure and prevents the reflux of urine to the upper segments is provided with many of desired hinders properties for urointestinal diversion.

Identification of bladder wall layers by Raman spectroscopy

PURPOSE

We explored the applicability of Raman spectroscopy to in situ investigation of bladder wall tissue.

MATERIALS AND METHODS

Bladder wall tissue was obtained from a guinea pig model and frozen sections were used for Raman spectroscopic investigations. From each section 500 to 700 spectra were obtained in a 2-dimensional grid spanning the urothelium, lamina propria and muscle layer. The data set of spectra was subdivided into groups of similar spectra by a cluster analysis algorithm. With each group assigned a different color Raman maps of frozen sections were constructed based on group membership of measured spectra. These maps were then compared with histological and histochemical data obtained from hematoxylin and eosin and immunohistochemical staining for collagen I and III and for smooth muscle actin to correlate Raman spectral features with bladder wall structure and molecular composition.

RESULTS

Urothelium, lamina propria and muscle layers could be clearly distinguished based on Raman spectra. Lamina propria spectra were dominated by signal contributions of collagen and the smooth muscle layer showed strong signal contributions of actin. The urothelium had a relatively strong lipid signal contribution.

CONCLUSIONS

These results and the fact that Raman spectroscopy is rapidly evolving into a technology that can be applied in vivo by thin, flexible fiberoptic catheters indicate that prospects are good for in vivo analysis of the molecular composition of the normal and pathological bladder without biopsies.

Identification of bladder wall layers by Raman spectroscopy

PURPOSE

We explored the applicability of Raman spectroscopy to in situ investigation of bladder wall tissue.

MATERIALS AND METHODS

Bladder wall tissue was obtained from a guinea pig model and frozen sections were used for Raman spectroscopic investigations. From each section 500 to 700 spectra were obtained in a 2-dimensional grid spanning the urothelium, lamina propria and muscle layer. The data set of spectra was subdivided into groups of similar spectra by a cluster analysis algorithm. With each group assigned a different color Raman maps of frozen sections were constructed based on group membership of measured spectra. These maps were then compared with histological and histochemical data obtained from hematoxylin and eosin and immunohistochemical staining for collagen I and III and for smooth muscle actin to correlate Raman spectral features with bladder wall structure and molecular composition.

RESULTS

Urothelium, lamina propria and muscle layers could be clearly distinguished based on Raman spectra. Lamina propria spectra were dominated by signal contributions of collagen and the smooth muscle layer showed strong signal contributions of actin. The urothelium had a relatively strong lipid signal contribution.

CONCLUSIONS

These results and the fact that Raman spectroscopy is rapidly evolving into a technology that can be applied in vivo by thin, flexible fiberoptic catheters indicate that prospects are good for in vivo analysis of the molecular composition of the normal and pathological bladder without biopsies.

An objective morphologic parameter to aid in the diagnosis of flat urothelial carcinoma in situ

The diagnosis of carcinoma in situ (CIS) lacks objective criteria and is subject to misdiagnosis. We identified 20 bladder biopsy cases each of CIS, urothelial dysplasia, and normal urothelium according to the 1998 World Health Organization/International Society of Urological Pathology consensus classification of urothelial neoplasms. Lymphocytes from 10 bladder biopsy specimens were chosen as reference cells. Using an image analysis system, we measured the following nuclear features: area, diameter, roundness, ellipticity, and optical density (maximum, minimum, mean, median, standard deviation, and quartiles). We measured a mean of 75 urothelial nuclei/case and a total of 500 lymphocytes. Roundness and ellipticity were not useful in distinguishing among the 3 groups. The best discriminators were mean nuclear area and mean nuclear area of the 25% largest nuclei (upper quartile) of urothelial cells compared with lymphocytes. The mean nuclear area relative to lymphocytes was 1.8 times (1.2 to 2.5 times) in normal urothelium, 2.4 times (1.6 to 3.0 times) in urothelial dysplasia, and 3.6 times (2.8 to 5.7 times) in CIS. The mean upper quartile nuclear area relative to lymphocytes was 2.2 times (1.4 to 2.8 times) in normal urothelium (P <.0001), 2.9 times (1.8 to 3.6 times) in urothelial dysplasia (P <.0001), and 4.9 times (4.0 to 7.6 times) in CIS (P <.0001). The difference in optical density was statistically significant between CIS and the other 2 histologic categories (P <.0001). Nuclear area is an easy and objective morphologic parameter for the evaluation of bladder biopsy specimens. Pathologists can assess the size of urothelial nuclei without using an image analysis system and compare them with the size of nuclei of lymphocytes, which are almost always present in a bladder biopsy specimen. Dysplasia, which is a somewhat ambiguous lesion, overlaps in its measurements with those of benign urothelium. The most useful morphologic parameter is the mean nuclear area of the 25% largest nuclei; CIS nuclei are approximately 5 times the size of lymphocytes, whereas normal urothelial nuclei are only 2 times the size of lymphocytes.

Discriminatory immunohistochemical staining of urothelial carcinoma in situ and non-neoplastic urothelium: an analysis of cytokeratin 20, p53, and CD44 antigens

Distinction of urothelial carcinoma in situ (CIS) from reactive atypia on the basis of morphology alone may be difficult in some cases. Because this distinction is therapeutically and prognostically critical, we attempted to determine if an immunohistochemical panel would help in this differential diagnosis. The immunoprofile of 21 cases of CIS and 25 non-neoplastic urothelia (15 urothelial biopsies with reactive atypia from patients without a history of bladder cancer and 10 normal ureter sections from nephrectomies performed for renal cell carcinoma) was determined using antibodies against cytokeratin 20 (CK20), p53, and CD44 (standard isoform). In the normal urothelium CK20 showed patchy cytoplasmic immunoreactivity in only the superficial umbrella cell layer and CD44 stained only the basal cells. Nuclear immunoreactivity to p53 varied from negative to weak and patchy. Reactive urothelium also showed CK20 immunoreactivity in only the umbrella cell layer in all 15 cases, and p53 nuclear staining was predominantly negative with occasional weak positivity in the basal and parabasal intermediate cells. CD44 was overexpressed in the entire reactive urothelium in 9 cases (60%) or focally positive in intermediate cells in 6 cases (40%). In contrast, CIS showed intense CK20 and p53 positivity (81% and 57%, respectively) in the majority (>50%) of malignant cells. CD44 staining revealed residual basal cells with membranous reactivity in 44% of the cases of CIS; however, the neoplastic cells were immunonegative in all cases. At least one positive immunomarker (CK20 or p53) was abnormally expressed in all cases of CIS. Abnormal expression of CK20 (increased), p53 (increased), and CD44 (decreased) in urothelial CIS, and increased expression of CD44 in reactive atypia allows more confident distinction of urothelial CIS from non-neoplastic urothelial atypias. From a differential diagnosis perspective, use of a panel of all three antibodies with morphologic correlation would be essential.

Everything you wanted to know about the bladder epithelium but were afraid to ask

The mammalian urinary bladder epithelium (urothelium) performs the important function of storing urine for extended periods, while maintaining the urine composition similar to that delivered by the kidneys. The urothelium possesses four properties to perform this function. First, it offers a minimum epithelial surface area-to-urine volume; this reduces the surface area for passive movement of substances between lumen and blood. Second, the passive permeability of the apical membrane and tight junctions is very low to electrolytes and nonelectrolytes. Third, the urothelium has a hormonally regulated sodium absorptive system; thus passive movement of sodium from blood to urine is countered by active sodium reabsorption. Last, the permeability properties of the apical membrane and tight junctions of the urothelium are not altered by most substances found in the urine or blood. The importance of the barrier function of the urothelium is illustrated by infectious cystitis. The loss of the barrier function results in the movement of urinary constituents into the lamina propria and underlying muscle layers, resulting in suprapubic and lower back pain and frequent, urgent, and painful voiding.

The World Health Organization/International Society of Urological Pathology consensus classification of urothelial (transitional cell) neoplasms of the urinary bladder. Bladder Consensus Conference Committee

This WHO/ISUP system is an attempt to develop as broad a consensus as possible in the classification of urothelial neoplasms, building upon earlier works and classification systems. It is meant to serve as a springboard for future studies that will help refine this classification, thus enabling us to provide better correlation of these lesions with their biologic behavior using uniform terminology.