A novel RGB-trichrome staining method for routine histological analysis of musculoskeletal tissues.

Morphometry and histology are essential approaches for investigation and diagnosis of musculo-skeletal disorders. Despite the advent of revolutionary methods of image analysis and high resolution three-dimensional imaging technology, basic conventional light microscopy still provides an incisive overview of the structure and tissue dynamics of the musculoskeletal system. This is crucial to both preclinical and clinical research, since several clinically relevant processes, such as bone repair, osteoarthritis, and metabolic bone diseases, display distinct, if not pathognomonic, histological features. Due to the particular characteristics of the skeletal tissues (i.e., the existence of mineralized extracellular matrices), a large number of staining methods applicable to either decalcified or undecalcified tissues are available. However, it is usually the case that several staining methods need to be sequentially applied in order to achieve the different endpoints required to fully assess skeletal tissue structure and dynamics, and to allow morphometric quantification. We describe herein a novel staining method, the RGB trichrome, amenable for application to decalcified, paraffin embedded human musculoskeletal tissues. The acronym RGB corresponds to the three primary dyes used: picrosirius Red, fast Green, and alcian Blue. Although these individual pigments are commonly used either isolated, in binary combinations, or as part of more complex polychrome staining methods, when merged in the RGB trichrome staining produce high-quality/high-contrast images, permitting not only clear identification of different tissues (i.e., the different types of cartilage, bone and fibrous connective tissue), but also discrimination between calcified and uncalcified bone and cartilage, as well as an unexpected diversity of shades of color, while displaying singular properties among polychrome staining methods, such as the unveiling of the bone osteocyte dendritic/canalicular network. Hence, we propose the RGB trichrome as simple but highly-reliable tool for the preclinical and clinical study of the musculoskeletal system.

FGFR3 and Cyclin D3 as urine biomarkers of bladder cancer recurrence.

AIM: To assess the diagnostic performance of FGFR3 and Cyclin D3 urinary protein levels in detecting bladder cancer recurrence. PATIENTS & METHODS: Urine of 321 patients in follow-up for bladder cancer and 150 non-neoplastic urine controls was included. Cytology, cystoscopy and FGFR3 and Cyclin D3 expression by western blot were performed. RESULTS: One hundred ten (34.3%) patients had evidence of tumor recurrence. The sensitivity and specificity of cytology/cystoscopy was 80 and 84%, and for FGFR3/Cyclin D3 was of 73 and 90%. CONCLUSION: Combined urinary FGFR3/Cyclin D3 expression shows improved detection rates for bladder cancer recurrence with high specificity and sensitivity, and within the same range of detection shown by cystoscopy, therefore supporting its potential use as noninvasive diagnostic biomarker for bladder cancer recurrence.

Myoepithelial cells in canine mammary tumours.

Mammary tumours are the most common neoplasms of female dogs. Compared to mammary tumours of humans and cats, myoepithelial (ME) cell involvement is common in canine mammary tumours (CMT) of any subtype. Since ME cell involvement in CMT influences both histogenetic tumour classification and prognosis, correct identification of ME cells is important. This review describes immunohistochemical methods for identification of canine mammary ME cells used in vivo. In addition, phenotypic and genotypic methods to isolate ME cells for in vitro studies to analyse tumour-suppressor protein production and gene expression are discussed. The contribution of ME cells to both histogenetic classifications and the prognosis of CMT is compared with other species and the potential use of ME cells as a method to identify carcinoma in situ is discussed.

Rare entities in urinary bladder pathology.

Bladder carcinoma with variant histology is a subject of recent interest, with data suggesting more aggressive behavior when compared with conventional urothelial carcinoma. The timely identification and recognition of these histological variants should avoid their misinterpretation as benign lesions. We emphasize the need to recognize these peculiar morphologic features since some of them may require a different/specific therapeutic approach. Other rare entities such as bladder polyps and myofibroblastic proliferations tend to occur at a younger age and represent specific problems in the differential diagnosis. We describe the salient clinicopathologic features of representative rare entities arising in the urinary bladder.

Dysplasia and carcinoma in situ of the urinary bladder.

Urothelial dysplasia (low-grade intraurothelial neoplasia) is recognized as a premalignant urothelial lesion in the 2004 World Health Organization (WHO) classification system. Although clarification of the diagnostic criteria of urothelial dysplasia has improved in recent years, there is still a lack of interobserver reproducibility. Active clinical follow-up is mandatory in patients with a diagnosis of urothelial dysplasia since it constitutes a marker of urothelial instability, and disease progression, in up to 19% of cases. The differential diagnosis of urothelial dysplasia is with other flat urothelial lesions with atypia, including flat urothelial hyperplasia, reactive urothelial atypia, urothelial atypia of unknown significance, and urothelial carcinoma in situ (high-grade intraurothelial neoplasia). In most cases, especially when small amounts of tissue are available, morphologic features alone may not be sufficient for diagnosis. Immunohistochemistry can be of help in selected cases, and a panel of cytokeratin 20, p53, and CD44 may help in the diagnosis. The use of HER2, p16, and Racemase remains as an option pending validation. Herein, we present the pathologic features and clinical significance of urothelial dysplasia and carcinoma in situ with emphasis on differential diagnosis from common flat lesions with atypia.

Bladder cancer: molecular determinants of personalized therapy.

Several molecular and genetic studies have provided new perspectives on the histologic classification of bladder tumors. Recent developments in the field of molecular mutational pathway analyses based on next generation sequencing technology together with classic data derived from the description of mutations in the FGFR3 (fibroblast growth factor receptor 3) gene, mutations on TP53 gene, and cDNA technology profiling data gives support to a differentiated taxonomy of bladder cancer. All these changes are behind the use of non-traditional approach to therapy of bladder cancer patients and are ready to change our daily practice of uro-oncology. The observed correlation of some molecular alterations with tumor behavior and the identification of their targets at cellular level might support the use of molecular changes together with morphological data to develop new clinical and biological strategies to manage patients with urothelial cancer. The current review provides comprehensive data to support personalized therapy for bladder cancer based on an integrated approach including pathologic and clinical features and molecular biology.

Clinicopathological characteristics and outcome of nested carcinoma of the urinary bladder.

We present the clinicopathological features of 56 cases of the nested variant of urothelial bladder carcinoma. This is an uncommon variant of bladder cancer, recognized by the current WHO classification of urologic tumors. The nested component represented 100 % of the tumor in 24 cases. The architectural pattern of the tumor varied from solid expansile to infiltrative nests characterized by deceptively bland histologic features resembling von Brunn nests. Typical features of high-grade conventional urothelial carcinoma were present in 32 cases. Most neoplastic cells had nuclei of low to intermediate nuclear grade with occasional nuclear enlargement, most frequently seen in deep areas of tumor. The nested component expressed cytokeratins 7, 20, CAM5.2, and high molecular weight (34ßE12), p63, Ki67, p53, p27, and GATA3. Tumor extension was T1 (n = 9), minimally T2 (n = 10), T2a (n = 1), T2b (n = 4), T3a (n = 8), T3b (n = 13), and T4a (n = 11). On follow-up, 36 of patients died of or were alive with disease from 2 to 80 months (mean 21 months). Four patients died of other causes. Eleven other patients remained disease free. Univariate survival analysis showed no differences for nested carcinoma compared with conventional urothelial carcinoma. As in conventional urothelial carcinoma, in nested carcinoma of the bladder pT category defined different survival groups. In summary, nested variant of urothelial bladder carcinoma is typically associated with advanced stage. In samples of limited volume, it may be misdiagnosed as proliferation of von Brunn nests or other nested-like bladder lesions, delaying definitive therapy.

Proto-oncogene HER-2 in normal, dysplastic and tumorous feline mammary glands: an immunohistochemical and chromogenic in situ hybridization study.

BACKGROUND: Feline mammary carcinoma has been proposed as a natural model of highly aggressive, hormone-independent human breast cancer. To further explore the utility of the model by adding new similarities between the two diseases, we have analyzed the oncogene HER-2 status at both the protein and the gene levels. METHODS: Formalin-fixed, paraffin-embedded tissue samples from 30 invasive carcinomas, 7 benign lesions and two normal mammary glands were analyzed. Tumour features with prognostic value were recorded. The expression of protein HER-2 was analyzed by immunohistochemistry and the number of gene copies by means of DNA chromogenic in situ hybridization. RESULTS: Immunohistochemical HER-2 protein overexpression was found in 40% of feline mammary carcinomas, a percentage higher to that observed in human breast carcinoma. As in women, feline tumours with HER-2 protein overexpression had pathological features of high malignancy. However, amplification of HER-2 was detected in 16% of carcinomas with protein overexpression, a percentage much lower than that observed in their human counterpart. CONCLUSION: Feline mammary carcinoma would be a suitable natural model of that subset of human breast carcinomas with HER-2 protein overexpression without gene amplification.