Variant histologies of bladder cancer (BC) often present with advanced tumor stage and the status of perioperative therapy is unclear. Thereby, squamous cell carcinoma (SCC), adenocarcinoma (ADENO), and sarcomatoid urothelial carcinoma (SARCO) are the most frequent variants. Nectin-4 has emerged as a highly interesting target in BC and might guide therapeutic application of antibody–drug conjugates (ADC). We therefore aimed to investigate expression patterns and prognostic value of Nectin-4 in variant histologies of BC. A single-center retrospective analysis was conducted of patients who underwent radical cystectomy (RC) for BC and revealed variant histologies of BC in the final specimens. Immunohistochemical staining for Nectin-4 was performed on tissue microarrays with 59 SCC, 22 ADENO, and 24 SARCO, and Nectin-4 expression was scored using the histochemical scoring system (H-score). Overall survival (OS) and progression-free survival (PFS) was calculated by Kaplan–Meier method. Median expression of Nectin-4 was 150 (range 0–250) in SCC, 140.5 (range 30–275) in ADENO, and 10 (0–185) in SARCO, with significantly lower levels for SARCO compared to SCC or ADENO (p < 0.001). For SCC, ADENO or SARCO no differences regarding OS or PFS were observed based on Nectin-4 expression levels (p > 0.05). Multivariate analysis revealed nodal stage as an independent prognostic factor for OS and PFS and metastases for PFS but not Nectin-4 expression. In conclusion, Nectin-4 was not prognostic in histological subtypes of BC in our study cohort. However, the high expression of Nectin-4 in SCC and ADENO might guide future treatment with novel Nectin-4-directed ADCs and provide this high-risk patient collective with a new promising therapeutic option. Testing Nectin-4 expression as a biomarker should be considered in trials with SARCO, where low Nectin-4 expression has been observed.

Background: [⁶⁸Ga]Ga-FAPI-46 is a novel positron emission tomography (PET) ligand that targets fibroblast activation protein (FAP) expression as FAP inhibitor (FAPI) and could already show promising results in several tumor entities. It could be demonstrated that an increased FAP expression correlates with tumor aggressivity in urothelial carcinoma (UC). Given the limited value of [¹⁸F]FDG in UC, [⁶⁸Ga]Ga-FAPI-46 could add diagnostic information in staging and response assessment in UC. We present the first data of [⁶⁸Ga]Ga-FAPI-46 PET imaging in a pilot cohort of UC patients evaluating uptake characteristics in metastases and primary tumors. Methods: Fifteen patients with UC prior to or after local treatment underwent [⁶⁸Ga]Ga-FAPI-46 PET/CT imaging for detection of metastatic spread. We compared the biodistribution in non-affected organs and tumor uptake of UC lesions by standard uptake value measurements (SUV_mean and SUV_max). Additionally, metastatic sites on PET were compared to its morphological correlate on contrast-enhanced computed tomography (CT). Results: Overall, 64 tumor sites were detected on PET and/or CT. The highest uptake intensity was noted at the primary site (SUV_max 20.8 (range, 8.1–27.8)) followed by lymph node metastases (SUV_max 10.6 (range, 4.7–29.1)). In 4/15 (26.7%) patients there were [⁶⁸Ga]Ga-FAPI-46-positive lesions that were missed on standard routine CT imaging. On the other hand, 2/15 patients had suspicious prominent bipulmonary nodules as well as pelvic lymph nodes previously rated as suspicious for metastatic spread on CT, but without increased FAPI expression; here histopathology excluded malignancy. Conclusion: [⁶⁸Ga]Ga-FAPI-46 PET shows distinctly elevated uptake in UC lesions. Therefore, the tracer has potential as a promising new biomarker in metastatic UC patients, as [⁶⁸Ga]Ga-FAPI-46 PET might improve detection of metastatic sites compared to CT alone. These findings highly emphasize larger studies investigating FAPI imaging in UC patients.

To establish prognostic genomic biomarkers for patients with metastatic clear cell renal cell carcinoma (ccRCC). We identified 60 patients who presented with metastatic ccRCC at our institution between 2001 and 2015 and had genomic sequencing on their primary tumor. We pooled these patients with 107 other patients with the same inclusion criteria from three well-known public databases. Five commonly mutated genes were chosen for analysis: VHL, PBRM1, BAP1, SETD2, and KDM5C. Overall survival (OS) was estimated using the Kaplan-Meier method and the log-rank test was used for comparisons between groups. Median OS in the cohort was 2.5 years. Higher Fuhrman grade was associated with decreased median OS (P<0.001). Mutations in SETD2 (P = 0.027) and KDM5C (P = 0.019) were associated with reduced risk of death (hazard ratio [HR] = 0.58 [95% CI: 0.35-0.94] and HR = 0.43 [95% CI: 0.22-0.85], respectively). BAP1 mutations (P = 0.008) were associated with increased risk of death (HR = 1.81 [95% CI: 1.16-2.83]). There were significantly more female patients with a BAP1 mutation than females in the overall cohort (P = 0.001). Mutations in BAP1 negatively affected OS, whereas SETD2 and KDM5C mutations were associated with prolonged OS in our pooled cohort of 167 patients with metastatic ccRCC. Our results expand upon efforts at understanding genomic biomarkers in localized disease. Those efforts set the stage for our novel investigation examining associations of select recurrent somatic mutations in stage IV patients with ccRCC.