Expression of uroplakin II and GATA-3 in bladder cancer mimickers: caveats in the use of a limited panel to determine cell of origin in bladder lesions.

Antibodies targeting uroplakin II (UPII) are highly specific for urothelial cells and are frequently used to determine if a primary bladder lesion or a metastatic lesion originates from the urothelium. However, to date, no studies have tested the expression of UPII in histological mimickers of bladder cancer that are nonurothelial in origin. Given the potential risk of misdiagnosis, immunohistochemical markers are often used to better characterize these lesions. In the present study, we analyzed the immunohistochemical expression of UPII in a set of urothelial carcinoma mimickers that included conventional nephrogenic adenoma (n = 8), papillary nephrogenic adenoma (n = 6), endometriosis/endosalpingiosis (n = 5), inflammatory myofibroblastic tumor (n = 4), ectopic prostate tissue (n = 2), and malakoplakia (n = 2). We also examined the expression of GATA-3, another commonly used immunohistochemical marker in bladder cancer diagnosis, in the same lesions. Weak immunoreactivity for UPII was identified in 6 of 27 mimickers (22%), and GATA-3 was expressed in 16 of 27 mimickers (59%). Strong immunoreactivity for UPII appeared to be a specific marker for urothelial cell of origin, although weak staining was seen in a significant proportion of mimickers. GATA-3 immunostaining was present in a greater number and broader spectrum of mimickers; however, only one case of papillary nephrogenic adenoma showed dual positivity for UPII and GATA-3. These findings support the immunohistochemical panel-based approach in the diagnosis of bladder lesions, especially if nonurothelial bladder cancer mimickers are in the differential diagnosis. Additional larger studies would be of value to expand on these findings.

Serous Carcinoma Mimicking Primary Urothelial Carcinoma on Clinical Evaluation and Pathology: A Potential Diagnostic Pitfall.

CONTEXT: - Serous carcinoma of the gynecologic tract often involves the external bladder wall and can occasionally mimic primary urothelial carcinoma of the bladder. OBJECTIVE: - To define the spectrum of morphologic and immunohistochemical features that characterize serous carcinoma involving the bladder wall and its distinction from urothelial carcinoma. DESIGN: - We reviewed all cases of serous carcinoma secondarily involving the bladder wall from the University of California San Diego and Polytechnic Institute for histopathologic and immunohistochemical features. RESULTS: - We identified 20 cases of Müllerian high-grade serous carcinoma involving the bladder wall. Five cases were clinical mimics of urothelial carcinoma, including 2 cases that presented as a large, transmural, primary bladder mass without precedent gynecologic history in women younger than 60 years, and 3 cases presumed to be new bladder carcinoma occurring distant to a serous carcinoma diagnosis. A subset of cases were morphologic mimics of urothelial carcinoma, which showed nested growth patterns (2 of 20; 10%), squamouslike foci (2 of 20; 10%), spindled/sarcomatoid growth (2 of 20; 10%), basaloid morphology (3 of 20; 15%), and syncytial growth patterns (1 of 20; 5%). Immunohistochemical stains in 17 cases showed immunoreactivity for CK7 (17 of 17; 100%), WT1 (17 of 17; 100%), uroplakin (UP) II (1 of 17; 6%), p63 (2 of 17; 12%), GATA3 (2 of 17; 12%), and PAX8 (17 of 17; 100%). CONCLUSIONS: - A subset of serous carcinomas involving the bladder wall can mimic urothelial carcinoma. Awareness of this mimicker and use of an immunohistochemical panel that includes CK7, WT1, UPII, PAX8, p63, and GATA3 can be helpful in confirming the diagnosis.

A combination of p40, GATA-3 and uroplakin II shows utility in the diagnosis and prognosis of muscle-invasive urothelial carcinoma.

Recently developed antibodies against uroplakin II and ΔNp63 (p40) show utility in diagnosing primary bladder urothelial carcinoma, although application in metastatic bladder cancer and patient outcomes has been less well defined. We evaluated these antibodies by immunostain intensity and H-score, in conjunction with GATA-3 immunoreactivity, in 89 patients with muscle-invasive urothelial carcinoma and 35 paired metastasis. The maintenance of immunoreactivity in metastatic lesions and the association to disease recurrence and survival was assessed. Bladder urothelial carcinoma showed immunoreactivity for GATA-3 in 99% (88/89), p40 in 87% (77/89) and uroplakin II in 80% (71/89) of cases, with a positive correlation between GATA-3 and uroplakin II H-score (0.44; p < 0.0001). All lesions were positive for at least one marker, reinforcing the use of these markers as a panel. In 35 patients with paired lymph node metastasis, uroplakin II and GATA-3 were retained in 90% and 75% of patients, respectively, suggesting these markers may have relatively high sensitivity in diagnosing metastatic urothelial carcinoma. High intensity p40 immunostain (3+), however, was significantly associated with reduced patient survival (p = 0.03). These results suggest that whereas GATA-3 and uroplakin II may be most useful in the diagnosis of urothelial carcinoma metastasis, p40 may be additionally suited as a prognostic marker.

A newly developed uroplakin II antibody with increased sensitivity in urothelial carcinoma of the bladder.

CONTEXT: Uroplakin II is a 15-kDa protein component of the urothelial plaques that enhance the permeability barrier and strength of the urothelium. Studies have shown uroplakin II messenger RNA to be expressed in bladder cancer tissues and peripheral blood of patients with urothelial carcinoma. Little is known about the protein expression of uroplakin II in urothelial carcinoma, possibly because of the absence of a commercially available uroplakin II antibody. Pathologists have used the uroplakin III antibody (AU1) to identify tumors of urothelial origin; however, the use of AU1 is limited because of its poor sensitivity. OBJECTIVES: To evaluate a newly developed mouse monoclonal uroplakin II antibody (BC21) in urothelial carcinoma and to compare it with previously developed mouse monoclonal uroplakin III (BC17 and AU1). DESIGN: Uroplakin II and III antibodies were optimized for staining using a horseradish peroxidase-polymer detection system and were visualized with 3,3'-diaminobenzidine. RESULTS: BC21, BC17, and AU1 demonstrated sensitivities in urothelial carcinoma of the bladder of 79% (44 of 56), 55% (31 of 56) (P = .002), and 34% (19 of 56) (P < .001), respectively. Subsequently, the increased staining sensitivity and intensity of BC21, compared with BC17, was validated in a larger study (134 of 174; 77% and 94 of 174; 54%, respectively) (P < .001). BC21 was found to be highly specific when evaluated in various normal and neoplastic tissues, including prostatic and renal carcinomas. CONCLUSIONS: The mouse monoclonal uroplakin II antibody (BC21) demonstrated superior sensitivity and specificity in urothelial carcinoma, compared with uroplakin III (BC17 and AU1), suggesting its advantages in the differential diagnosis of urothelial carcinoma and in the detection of tumors of unknown origin.

Folate receptor α associated with triple-negative breast cancer and poor prognosis.

CONTEXT: Folate receptor α (FRA) has been shown to be selectively expressed in several types of human cancer, including breast cancer. Currently, several FRA target therapies are under intensive study. OBJECTIVE: To investigate the expression pattern of FRA in a large cohort of patients with breast cancer and analyze its relationship with different clinicopathologic features, with expression of several key biomarkers, and with clinical outcome. DESIGN: Four hundred forty-seven cases of infiltrating ductal carcinoma diagnosed between 1997 and 2008 at the University of Rochester Medical Center were identified and reviewed, and 25 blocks of tissue microassays were constructed. The association between expression of FRA and clinicopathologic features; expression of estrogen receptor (ER), progesterone receptor (PR), HER2/neu, and Ki-67; and clinical outcome of these tumors were evaluated. RESULTS: The expression of FRA was significantly associated with tumors with high histologic grade, higher nodal stages, ER/PR negativity, and high proliferative activity (Ki-67 ≥ 15%), and was independent of HER2/neu overexpression. In all, 74% of ER/PR-negative and 80% of triple-negative breast cancers expressed FRA. The expression of FRA was significantly associated with a worse disease-free survival. CONCLUSIONS: Our data demonstrate that a significant subgroup of ER/PR-negative and triple-negative breast cancers express FRA, and its expression is associated with worse clinical outcome.

Interobserver agreement and assay reproducibility of folate receptor α expression in lung adenocarcinoma: a prognostic marker and potential therapeutic target.

CONTEXT: Lung cancer is the leading cause of cancer deaths in the United States and globally. Folate-targeted drugs are among the promising new targeted therapies for lung cancer, provided predictive biomarkers can be identified for optimal patient selection. OBJECTIVE: To evaluate the interobserver agreement and reproducibility of an immunohistochemistry assay for folate receptor α as a potential predictive marker for folate-targeted therapies. DESIGN: Immunohistochemistry using anti-folate receptor α antibody 26B3 was performed on formalin-fixed, paraffin-embedded tissues. The M-score, a semiquantitative measure of staining intensity and proportion of tumor cells staining, was determined for each specimen. Interobserver agreement was assessed using lung adenocarcinoma specimens stained at a single site and evaluated by 3 independent pathologists. Interinstrument reproducibility assessed 20 specimens stained by 3 different automated stainers. Interlaboratory agreement was determined on 5 specimens, repeatedly stained on each of 5 days, at 3 different study sites. RESULTS: Folate receptor α expression was identified in 39 of 54 cases of lung adenocarcinoma (72%) and 4 of 37 cases of lung squamous cell carcinoma (11%). Agreement among 3 pathologists was found in 24 of 26 cases (92%). Interinstrument reproducibility was observed in 19 of 20 cases (95%). Agreement among 3 laboratories was found for 49 of 50 specimens (98%). CONCLUSIONS: Immunostaining of folate receptor α in lung adenocarcinomas is reproducible across staining platforms and among laboratories. Agreement among pathologists is achieved using a semiquantitative scoring method. An accurate and convenient method for determining folate receptor α expression offers a potentially invaluable tool for selecting patients for folate-targeted therapies.

Use of p63/P504S monoclonal antibody cocktail in immunohistochemical staining of prostate tissue.

Diagnosis of prostate needle biopsies can be challenging, particularly when the atypical areas of interest are very small. The utility of immunostains for high-molecular-weight cytokeratin (34betaE12) to highlight prostatic basal cells in these cases is well established, and recent reports also document the utility of immunostains for p63 (a marker that stains the nuclei of prostate basal cells) for this purpose. Several investigators have demonstrated that immunostaining for P504S, a cytoplasmic protein that is overexpressed in a high percentage of prostate cancers and in many cases of high-grade prostatic intraepithelial neoplasia (PIN), can also be of use in the diagnosis of prostate biopsies. Because of the cytoplasmic localization of P504S and nuclear localization of p63, the authors hypothesized that a cocktail of these two antibodies might allow simultaneous demonstration of P504S and p63 using a single immunostain. In this report the authors describe the successful use of a cocktail of p63/P504S for immunohistochemical staining of prostate tissue. Two different staining approaches were investigated, with essentially identical results. This cocktail localizes P504S in the cytoplasm of prostate carcinoma cells and high-grade PIN and demonstrates the nuclei of prostatic basal cells, providing information on both the status of P504S and the presence or absence of basal cells with a single immunostain. This cocktail can be of great utility in the examination of diagnostically challenging prostate specimens.