Uroplakin II (UPII), GATA3, and p40 are Highly Sensitive Markers for the Differential Diagnosis of Invasive Urothelial Carcinoma.

Distinguishing between invasive urothelial carcinoma from other genitourinary lesions such as prostatic and renal carcinomas can be difficult, and may require highly sensitive immunohistochemical markers. GATA-binding protein 3 (GATA3) has been reported in a high percentage of urothelial and breast carcinomas. Mouse monoclonal uroplakin II (UPII) and p40 antibodies have recently been developed and demonstrated high specificity in urothelial carcinoma. This study evaluated the immunohistochemical staining sensitivities of UPII, GATA3, p40, and p63 in the detection of invasive urothelial carcinoma. UPII, GATA3, and p40 were further tested for specificity in lung, breast, colon, kidney, and prostate cancers. In all invasive urothelial carcinoma cases, UPII, GATA3, p40, and p63 exhibited sensitivities of 77.7%, 83.5%, 85.4%, and 80.6%, respectively. The combination of UPII, GATA3, and p40 antibodies stained 94.2% (97/103) of all invasive urothelial carcinoma cases, including 92.2% (71/77) of grade 2-3 urothelial carcinomas. In addition, GATA3 and UPII showed negative staining in lung squamous cell carcinomas and p40 showed negative staining in breast infiltrating ductal carcinomas. The combination of UPII, GATA3, and p40 showed negative staining in lung adenocarcinoma, colon adenocarcinoma, and renal carcinomas. In conclusion, UPII, GATA3, and p40, when used in combination, are highly sensitive in the differential diagnosis of invasive urothelial carcinoma.

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.

Principles of analytic validation of immunohistochemical assays: Guideline from the College of American Pathologists Pathology and Laboratory Quality Center.

CONTEXT: Laboratories must validate all assays before they can be used to test patient specimens, but currently there are no evidence-based guidelines regarding validation of immunohistochemical assays. OBJECTIVE: To develop recommendations for initial analytic validation and revalidation of immunohistochemical assays. DESIGN: The College of American Pathologists Pathology and Laboratory Quality Center convened a panel of pathologists and histotechnologists with expertise in immunohistochemistry to develop validation recommendations. A systematic evidence review was conducted to address key questions. Electronic searches identified 1463 publications, of which 126 met inclusion criteria and were extracted. Individual publications were graded for quality, and the key question findings for strength of evidence. Recommendations were derived from strength of evidence, open comment feedback, and expert panel consensus. RESULTS: Fourteen guideline statements were established to help pathology laboratories comply with validation and revalidation requirements for immunohistochemical assays. CONCLUSIONS: Laboratories must document successful analytic validation of all immunohistochemical tests before applying to patient specimens. The parameters for cases included in validation sets, including number, expression levels, fixative and processing methods, should take into account intended use and should be sufficient to ensure that the test accurately measures the analyte of interest in specimens tested in that laboratory. Recommendations are also provided for confirming assay performance when there are changes in test methods, reagents, or equipment.

A new rabbit monoclonal E-cadherin antibody [EP700Y] shows higher sensitivity than mouse monoclonal E-cadherin [HECD-1] antibody in breast ductal carcinomas and does not stain breast lobular carcinomas.

Immunohistochemical studies have shown E-cadherin to be expressed in breast carcinomas showing a ductal histology, with a corresponding loss of expression in tumors with a lobular histology. As a result, mouse monoclonal anti-E-cadherin [HECD-1] has been used by pathologists to differentiate between ductal and lobular carcinomas, with currently published sensitivity and specificity rates of approximately 90%. Rabbit monoclonal antibodies may combine the best properties of both mouse monoclonal antibodies and rabbit antisera. Therefore, this study compares the staining sensitivity and specificity of a new rabbit monoclonal E-cadherin and the standard mouse monoclonal E-cadherin [HECD-1] in breast ductal carcinomas, and evaluates a cocktail of rabbit monoclonal E-cadherin and p120 catenin in the discrimination of ductal from lobular carcinomas. The rabbit E-cadherin showed sharper staining and increased sensitivity (80/81, 99%) than the mouse E-cadherin (75/81, 93%). The rabbit E-cadherin achieved a score of 3+ in 85.2% (69/81) of cases as compared with a 3+ in only 21.0% (17/81) of cases stained with mouse E-cadherin. All lobular carcinomas (n=37) were confirmed by the absence of E-cadherin and the diffuse cytoplasmic expression of p120 catenin. Although both the single mouse E-cadherin and dual stain can differentiate ductal from lobular lesions, the dual stain is helpful in challenging cases because of its bright pink p120 catenin and dark brown rabbit E-cadherin staining. The highly sensitive rabbit E-cadherin antibody is the preferred antibody for evaluating ductal carcinomas and for distinguishing ductal versus lobular lesions, and the dual stain was superior to the single E-cadherin stain.

The College of American Pathologists and National Society for Histotechnology workload study.

Limited data exist in regard to productivity and staffing in the anatomic pathology laboratory. In 2004, the National Society for Histotechnology (NSH) conducted a pilot study to examine productivity and staffing in the histology laboratory. After review of the data, The College of American Pathologists (CAP)/NSH Histotechnology Committee concluded that a larger survey was required to further address and expand on the pilot study findings. In 2007, a total of 2674 surveys were sent out to North American laboratories. From the responses, comparisons of laboratory demographics and productivity were examined by institution type and workload volume. Productivity was measured as the number of paraffin-embedded tissue blocks processed per full-time equivalent per year. This manuscript presents and discusses the data collected from the CAP/NSH Workload Study.