No abstract

Distinguishing invasive high-grade urothelial carcinoma (UC) from other carcinomas occurring in the genitourinary tract may be difficult. The differential diagnosis includes high-grade prostatic adenocarcinoma, spread from an anal squamous cell carcinoma (SCC), or spread from a uterine cervical SCC. In terms of metastatic UC, the most common problem is differentiating spread of UC to the lung versus a primary pulmonary SCC. Immunohistochemistry (IHC) for GATA binding protein 3 (GATA3), thrombomodulin (THROMBO), and Uroplakin III was performed on a tissue microarray (TMA) containing 35 cases of invasive high-grade UC. GATA3 IHC was also performed on TMAs containing 38 high-grade (Gleason score 8) prostatic adenocarcinomas, representative tissue sections from 15 invasive anal SCCs, representative tissue sections from 19 invasive cervical SCCs, and TMAs with 12 invasive cervical carcinomas of the cervix [SCC (n=10), SCC with neuroendocrine features (n=1), adenosquamous carcinoma (n=1)]. Additionally, GATA3 IHC was performed on representative tissue sections from 15 pulmonary UC metastases and a TMA with 25 SCCs of the lung and 5 pulmonary non-small cell carcinomas with squamous features. GATA3, THROMBO, and Uroplakin III were positive in 28 (80%), 22 (63%), and 21 (60%) cases of high-grade UC, respectively. All GATA3 positive staining was non-focal, 25 (89%) cases demonstrated moderate-strong staining, and 3 (11%) cases demonstrated weak staining. Of the 7 cases that failed to express GATA3, 5 were positive for THROMBO and/or Uroplakin III, while 2 cases were negative for all 3 markers. None of 38 high-grade prostatic adenocarcinomas were positive for GATA3. Weak GATA3 staining was present in occasional basal cells of benign prostate glands, in a few benign atrophic glands, and in urothelial metaplasia. Of the 15 cases of anal SCCs, 2 (7%) cases showed focal weak staining and 1 (3%) case showed focal moderate staining. Weak staining was also rarely observed in the benign anal squamous epithelium. Of the 31 uterine cervical carcinomas, 6 (19%) showed weak GATA3 staining (3 non-focal, 3 focal) and 2 (6%) demonstrated focal moderate staining. Twelve (80%) of the metastatic UC to the lung were positive for GATA3 with 11 cases showing diffuse moderate or strong staining and 1 case showing focal moderate staining. None of the pulmonary SCC or non-small cell carcinomas with squamous features were GATA3 positive. GATA3 IHC is a sensitive marker for UC and positive staining in UC is typically non-focal and moderate or strong in intensity. GATA3 is also highly specific in excluding high-grade prostate adenocarcinoma. Although some cervical and anal SCCs can be GATA3 positive, unlike in UC, staining is more commonly focal and weak. GATA3 is also a useful maker when diagnosing metastatic UC to the lung.

Bladder cancer is the fifth most common in incidence and one of the most expensive cancers to treat. Early detection greatly improves the chances of survival and bladder preservation. The pH low insertion peptide (pHLIP) conjugated with a near-infrared fluorescent dye [indocyanine green (ICG)] targets low extracellular pH, allowing visualization of malignant lesions in human bladder carcinoma ex vivo. Cystectomy specimens obtained after radical surgery were immediately irrigated with nonbuffered saline and instilled with a solution of the ICG pHLIP construct, incubated, and rinsed. Bladders were subsequently opened and imaged, the fluorescent spots were marked, and a standard pathological analysis was carried out to establish the correlation between ICG pHLIP imaging and white light pathological assessment. Accurate targeting of bladder lesions was achieved with a sensitivity of 97%. Specificity is 100%, but reduced to 80% if targeting of necrotic tissue from previous transurethral resections or chemotherapy are considered as false positives. The ICG pHLIP imaging agent marked high-grade urothelial carcinomas, both muscle invasive and nonmuscle invasive. Carcinoma in situ was accurately diagnosed in 11 cases, whereas only four cases were seen using white light, so imaging with the ICG pHLIP peptide offers improved early diagnosis of bladder cancers and may also enable new treatment alternatives.bladder cancer | fluorescence-guided surgery | NIR imaging | acidity | human tissue