Pancreatic ductal adenocarcinoma (PDA) is among the most lethal human cancers, in part because it is insensitive to many chemotherapeutic drugs. Studying a mouse model of PDA that is refractory to the clinically used drug gemcitabine, we found that the tumors in this model were poorly perfused and poorly vascularized, properties that are shared with human PDA. We tested whether the delivery and efficacy of gemcitabine in the mice could be improved by coadministration of IPI-926, a drug that depletes tumor-associated stromal tissue by inhibiting the † To whom correspondence should be addressed. david.tuveson@cancer.org.uk.

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.

With the current understanding that nitric oxide (NO) mediates penile erection, the endothelial isoform of NO synthase (eNOS) has been implicated in this function. We undertook this study applying transgenic mice with targeted deletion of the eNOS gene (eNOSϪ/Ϫ mice) as an experimental approach to evaluate the importance of eNOS in cholinergically stimulated erectile function in vivo. Combined pharmacostimulation with intracavernosal carbachol (3 ng) administration and submaximal cavernous nerve (CN) electrical stimulation (16 Hz, 5 millisecond, 1 V) simultaneous with intracavernosal pressure (ICP) monitoring, and both biochemical assay of NO synthase activity and Western blot analysis of eNOS protein content in penile tissue, were performed on eNOSϪ/Ϫ mice and wild-type controls. Combined intracavernosal carbachol administration and submaximal CN electrical stimulation raised the recorded ICP, elicited by CN electrical stimulation alone in wild-type mice (from 35.7 Ϯ 2.7 to 48.1 Ϯ 5.5 mm Hg, P Ͻ .05) but not in eNOSϪ/ Ϫ mice (from 54.9 Ϯ 6.3 to 51.0 Ϯ 9.5 mm Hg, not significant [NS]). Pretreatment with the nonselective nitric oxide synthase inhibitor nitro-L-arginine methyl ester (L-NAME; 100 mg intracavernosally) blocked electrically stimulated ICP responses in eNOSϪ/Ϫ mice to baseline levels (37.8 Ϯ 4.4 vs 12.7 Ϯ 4.0 mm Hg, P Ͻ .05). In penes of eNOSϪ/Ϫ mice, approximately 60% NO synthase activity of wildtype penis levels was retained (NS), and eNOS protein was absent. We concluded that eNOSϪ/Ϫ mice preserve erectile function on the basis of a noncholinergic but NO-dependent mechanism and that eNOS physiologically mediates penile erection under cholinergic stimulation.