Proteomic Strategies to Reveal Tumor Heterogeneity among Urothelial Papillomas

Abstract

Proteomics and immunohistochemistry were used to reveal tumor heterogeneity among urothelial papillomas (UPs) with the long term goal of predicting their biological potential in terms of outcome. First, we identified proteins that were deregulated in invasive fresh lesions as compared with normal urothelium, and thereafter we immunostained UPs with a panel of antibodies against some of the markers. Twenty-two major proteins showing variations of 2-fold or more in at least one-third of the invasive lesions were selected. Specific antibodies against several of the proteins were obtained, but only a few reacted positively in immunostaining. A panel consisting of antibodies against keratinocytes (CKs) 5, 13, 18, and 20 and markers of squamous metaplasia (CKs 7, 8, and 14) was used to probe normal urothelium and 30 UPs collected during a period of five years. Four UPs showed a normal phenotype, whereas the rest could be grouped in five major types that shared aberrant staining with the CK20 antibody. Type 1 heterogeneity (n ‫؍‬ 4) showed preferred staining of the umbrella cells with the CK8 antibody. Type 2 (n ‫؍‬ 11) was typified by the staining of the basal and intermediate layers with the CK20 antibody. Type 3 (n ‫؍‬ 7) was characterized by the predominant staining of the basal cell layer with the CK5 antibody. Type 4 (n ‫؍‬ 1) showed areas of CK7 negative cells, whereas type 5 (n ‫؍‬ 3) showed loss of staining of the basal cells with the CK20. 29% of the patients experienced recurrences, but none progressed to invasive disease. Patients harboring phenotypic alterations in the basal cell compartment (types 3 and 5) showed the highest number of recurrences (4/7 and 2/3, respectively), and all type 3 lesions progressed to a higher degree of dedifferentiation. Even though a long term prospective study involving a larger sample size is required to assess the biological potential of these lesions, we believe that this approach will prove instrumental for revealing early phenotypic changes in different types of cancer. Molecular & Cellular Proteomics 1:269 -279, 2002.

Protein Profiling of the Human Epidermis from the Elderly Reveals Up-regulation of a Signature of Interferon-γ-induced Polypeptides That Includes Manganese-superoxide Dismutase and the p85β Subunit of Phosphatidylinositol 3-Kinase

“…2. Samples showed little contamination with connective tissue as judged by the low levels of expression of vimentin, a protein that is expressed by dermal fibroblasts (41). A total of 172 well focused and abundant proteins were selected for quantitation (Table I).…”

Expression of the Tumor Suppressor Protein 14-3-3σ Is Down-regulated in Invasive Transitional Cell Carcinomas of the Urinary Bladder Undergoing Epithelial-to-Mesenchymal Transition

“…7E, 898-3 pTa G1) or invasive lesions (Fig. 7F, 738 pT1 G3), most likely reflecting tumor type differences (20). Highly invasive TCCs, on the other hand, showed homogenous staining (Fig.…”

“…For many years, we have carried out a systematic and comprehensive proteomic analysis of bladder tumors in an effort to identify protein markers that may form the basis for improved diagnosis, prognosis, and new forms of treatment (19,20). The strategy we have employed is based on the systematic comparison of the proteome expression profiles of fresh tissue biopsies from normal and malignant urothelium.…”

Bladder Cancer-associated Protein, a Potential Prognostic Biomarker in Human Bladder Cancer

“…Toward this aim, we have examined the protein expression profiles of more than 1,000 samples (benign as well as tumors of various histopathological grades and stages) using gel-based proteomics, and we have identified a number of potentially useful biomarkers, such as adipocyte-type fatty acid-binding protein (A-FABP), 14-3-3 protein isoform , psoriasin (S100A7), GST Mu, 15-hydroxyprostaglandin dehydrogenase, tropomyosin 4, disulfide isomerase precursor (ERP60), homeobox protein (HOX-1.3), keratins 8 and 13, MRP-14, CD24, and the cytochrome oxidase III subunit among others (5)(6)(7)(8)(9)(10)(11)(12), whose expression strongly correlates with a particular step of bladder cancer progression.…”