Probes for LONG

Although a putative role for TGF beta (TGFB) signaling in the pathogenesis of human endometrial cancer has long been proposed, the precise function of TGFB signaling in the development and progression of endometrial cancer remains elusive. Depletion of PTEN in the mouse uterus causes endometrial cancer. To identify the potential role of TGFB signaling in endometrial cancer, we simultaneously deleted TGFB receptor 1 (Tgfbr1) and Pten in the mouse uterus using Cre-recombinase driven by the progesterone receptor (termed Ptend/d ; Tgfbr1d/d ). We found that Ptend/d ; Tgfbr1d/d mice developed severe endometrial lesions that progressed more rapidly compared with those resulting from conditional deletion of Pten alone, suggesting that TGFB signaling synergizes with PTEN to suppress endometrial cancer progression. Remarkably, the Ptend/d ; Tgfbr1d/d mice developed distant pulmonary metastases, leading to significantly reduced life span. The development of metastasis and accelerated tumor progression in Ptend/d ; Tgfbr1d/d mice are associated with increased production of pro-inflammatory chemokines, enhanced cancer cell motility evidenced by myometrial invasion and disruption, and altered tumor microenvironment characterized by recruitment of tumor-associated macrophages. Thus, conditional deletion of Tgfbr1 in PTEN-inactivated endometrium leads to a disease that recapitulates invasive and lethal human endometrial cancer. This mouse model may be valuable for preclinical testing of new cancer therapies, particularly those targeting metastasis, one of the hallmarks of cancer and a major cause of death in endometrial cancer patients.

Therapy with anti-PD-L1 immune check-point inhibitors is approved for several cancers, including advanced urothelial carcinomas. PD-L1 prevalence estimates vary widely in bladder cancer, and lack of correlation between expression and clinical outcomes and immunotherapyresponse may be attributed to methodological differences of the immunohistochemical reagents and procedures. We characterized PD-L1 expression in 235 urothelial carcinomas including 79 matched pairs of primary and metastatic cancers using a panel of four PD-L1 immunoassays in comparison with RNAscope assay using PD-L1-specific probe (CD274). The antibody panel included three FDA-approved clones (22C3 for pembrolizumab, 28.8 for nivolumab, SP142 for atezolizumab), and a commonly used clone E1L3N. Manual scoring of tissue microarrays was performed in each of 235 tumors (624 tissue cores) and compared to an automated image analysis. Expression of PD-L1 in tumor cells by ≥1 marker was detected in 41/142 (28.9%) primary tumors, 13/77 (16.9%) lymph nodes, and 2/16 (12.5%) distant metastases. In positive cases, high PD-L1 expression (>50% cells) was detected in 34.1% primary and 46.7% metastases. Concordant PD-L1 expression status was present in 71/79 (89.9%) cases of matched primary and metastatic urothelial carcinomas. PD-L1 sensitivity ranked from highest to lowest as follows: RNAscope, clone 28.8, 22C3, E1L3N, and SP142. Pairwise concordance correlation coefficients between the four antibodies in 624 tissue cores ranged from 0.76 to 0.9 for tumor cells and from 0.30 to 0.85 for immune cells. RNA and protein expression levels showed moderate to high agreement (0.72-0.87). Intra-tumor expression heterogeneity was low for both protein and RNA assays (interclass correlation coefficients: 0.86-0.94). Manual scores were highly concordant with automated Aperio scores (0.94-0.97). A significant subset of 56/235 (23.8%) urothelial carcinomas stained positive for PD-L1 with high concordance between all four antibodies and RNA ISH assay. Despite some heterogeneity in staining, the overall results are highly concordant suggesting diagnostic equivalence of tested assays.