Pure high-grade papillary urothelial bladder cancer: a luminal-like subgroup with potential for targeted therapy

Abstract

Purpose Non-invasive high-grade (HG) bladder cancer is a heterogeneous disease that is characterized insufficiently. First-line Bacillus Calmette-Guérin instillation fails in a substantial amount of cases and alternative bladder-preserving treatments are limited, underlining the need to promote a further molecular understanding of non-invasive HG lesions. Here, we characterized pure HG papillary urothelial bladder cancer (pure pTa HG), a potential subgroup of non-invasive HG bladder carcinomas, with regard to molecular subtype affiliation and potential for targeted therapy. Methods An immunohistochemistry panel comprising luminal (KRT20, ERBB2, ESR2, GATA3) and basal (KRT5/6, KRT14) markers as well as p53 and FGFR3 was used to analyze molecular subtype affiliations of 78 pure pTa HG/papillary pT1(a) HG samples. In 66 of these, ERBB2 fluorescence in situ hybridization was performed. Additionally, targeted sequencing (31 genes) of 19 pTa HG cases was conducted, focusing on known therapeutic targets or those described to predict response to targeted therapies noted in registered clinical trials or that are already approved. Results We found that pure pTa HG/papillary pT1(a) HG lesions were characterized by a luminal-like phenotype associated with frequent (58% of samples) moderate to high ERBB2 protein expression, rare FGFR3 alterations on genomic and protein levels, and a high frequency (89% of samples) of chromatin-modifying gene alterations. Of note, 95% of pTa HG/papillary pT1 HG cases harbored at least one potential druggable genomic alteration. Conclusions Our data should help guiding the selection of targeted therapies for investigation in future clinical trials and, additionally, may provide a basis for prospective mechanistic studies of pTa HG pathogenesis.

Non-Muscle-Invasive Bladder Carcinoma with Respect to Basal Versus Luminal Keratin Expression

“…In addition, chromatin-modifying genes, such as KDM5B and SMARCA4 , were activated in both the K5/6-only and K5/6-only_Lund groups more than would be expected randomly. Together with recent mutational data [ 29 ], findings regarding these molecules reveal an opportunity for targeted therapy in K5/6 High -K20 Low NMIBC.…”

Intratumoral heterogeneity of surrogate molecular subtypes in urothelial carcinoma in situ of the urinary bladder: implications for prognostic stratification of high-risk non-muscle-invasive bladder cancer

“…Slides were subsequently transferred to an automated immunostainer (Dako, Agilent) and covered with EnVision TM Flex Peroxidase Blocking-Reagent (Dako, Agilent) for 5 min. Next, immunostaining was performed using validated antibodies for KRT20, GATA3, ERBB2, KRT5/6, KRT14, and p53 [ 14 , 15 ]. Subsequently, tissue sections were treated with a secondary reagent (Dako, Agilent) for 15 min, followed by incubation with a horseradish peroxidase-conjugated polymer (Dako, Agilent) for 20 min.…”

“…The percentage of positively stained cells was evaluated for the cytoplasmic markers KRT20, KRT5/6, KRT14, and nuclear p53. As described previously [ 14 , 15 ], KRT20, KRT5/6, and KRT14 immunohistochemistry were evaluated with cutoffs of >50% as positive. This value seems plausible to the experienced uropathologist, since it is sometimes hard to unequivocally exclude reactive changes of basal cells (KRT5/6 and KRT14 positive) and regenerative superficial cells (KRT20 positive), which may well be mixed in with the cells of carcinoma in situ.…”

“…The percentage of positively stained cells was evaluated for the cytoplasmic markers KRT20, KRT5/6, KRT14, and nuclear p53. As described previously [14,15], KRT20, KRT5/6, and KRT14 immunohistochemistry were evaluated with cutoffs of >50% as positive.…”

In Situ Vaccination as a Strategy to Modulate the Immune Microenvironment of Hepatocellular Carcinoma

“…The most established bacterial immunotherapy for solid tumors is Bacillus Calmette-Guerin (BCG). It is routinely used intravesically in bladder cancer as an immunogenic adjuvant treatment after resection of high-grade, early-stage tumors (98,99), while the search for targeted treatments for these tumors are still ongoing (100,101). BCG induces multifaceted immunological effects.…”