Clinical sequencing identifies potential actionable alterations in a high rate of urachal and primary bladder adenocarcinomas.

OBJECTIVE: Administration of targeted therapies provides a promising treatment strategy for urachal adenocarcinoma (UrC) or primary bladder adenocarcinoma (PBAC); however, the selection of appropriate drugs remains difficult. Here, we aimed to establish a routine compatible methodological pipeline for the identification of the most important therapeutic targets and potentially effective drugs for UrC and PBAC. METHODS: Next-generation sequencing, using a 161 cancer driver gene panel, was performed on 41 UrC and 13 PBAC samples. Clinically relevant alterations were filtered, and therapeutic interpretation was performed by in silico evaluation of drug-gene interactions. RESULTS: After data processing, 45/54 samples passed the quality control. Sequencing analysis revealed 191 pathogenic mutations in 68 genes. The most frequent gain-of-function mutations in UrC were found in KRAS (33%), and MYC (15%), while in PBAC KRAS (25%), MYC (25%), FLT3 (17%) and TERT (17%) were recurrently affected. The most frequently affected pathways were the cell cycle regulation, and the DNA damage control pathway. Actionable mutations with at least one available approved drug were identified in 31/33 (94%) UrC and 8/12 (67%) PBAC patients. CONCLUSIONS: In this study, we developed a data-processing pipeline for the detection and therapeutic interpretation of genetic alterations in two rare cancers. Our analyses revealed actionable mutations in a high rate of cases, suggesting that this approach is a potentially feasible strategy for both UrC and PBAC treatments.

Prevalence of APC and PTEN Alterations in Urachal Cancer.

Urachal carcinoma (UrC) is a rare tumor with remarkable histological and molecular similarities to colorectal cancer (CRC). Adenomatous polyposis coli (APC) is the most frequently affected gene in CRC, but the prevalence and significance of its alterations in UrC is poorly understood. In addition, loss of phosphatase and tensin homologue (PTEN) was shown to be associated with therapy resistance in CRC. Our primary aim was to assess specific genetic alterations including APC and PTEN in a large series of UrC samples in order to identify clinically significant genomic alterations. We analyzed a total of 40 UrC cases. Targeted 5-gene (APC, PTEN, DICER1, PRKAR1A, TSHR, WRN) panel sequencing was performed on the Illumina MiSeq platform (n = 34). In addition, ß-catenin (n = 38) and PTEN (n = 30) expressions were assessed by immunohistochemistry. APC and PTEN genes were affected in 15% (5/34) and 6% (2/34) of cases. Two of five APC alterations (p.Y1075*, p.K1199*) were truncating pathogenic mutations. One of the two PTEN variants was a pathogenic frameshift insertion (p.C211fs). In 29% (11/38) of samples, at least some weak nuclear ß-catenin immunostaining was detected and PTEN loss was observed in 20% (6/30) of samples. The low prevalence of APC mutations in UrC represents a characteristic difference to CRC. Based on APC and ß-catenin results, the Wnt pathway seems to be rarely affected in UrC. Considering the formerly described involvement of PTEN protein loss in anti-EGFR therapy-resistance its immunohistochemical testing may have therapeutic relevance.

Urothelial Carcinoma in Bladder Diverticula: A Multicenter Analysis of Characteristics and Clinical Outcomes.

BACKGROUND: Urothelial carcinoma arising in a bladder diverticulum (UCBD) is uncommon, and data on treatment and outcome are sparse. OBJECTIVE: To analyze clinicopathological characteristics of UCBD and to compare outcome after radical cystectomy (RC) and partial cystectomy (PC). DESIGN, SETTING, AND PARTICIPANTS: Data of 115 UCBD patients treated with RC (n=81) or PC (n=34) between 2000 and 2016 were collected from 11 institutional databases and were analyzed retrospectively. Median follow-up was 5.0yr (95% confidence interval [CI]: 4.0-6.2). OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Upstaging of tumor stage at diagnostic transurethral resection (TUR) to the RC/PC specimen was investigated. Overall survival (OS) and metastasis-free survival (MFS) after RC and PC were analyzed using Kaplan-Meier estimates, and compared using the log-rank test. Intravesical recurrences after PC were reported. A multivariable Cox proportional-hazard model was used to identify factors associated with OS. RESULTS AND LIMITATIONS: There were no statistically significant differences in clinicopathological characteristics between RC and PC groups. Fifty-five percent of patients with cTa/is/1 at diagnostic TUR had ≥pT2 tumors at RC/PC. Five-year OS and MFS were, respectively, 62% and 66% for RC and 66% and 55% for PC (p=0.9 and p=0.6). Intravesical tumor recurrence was seen in six of 34 (18%) PC patients. In multivariable analysis, positive surgical margins and extravesical disease (≥pT2) were associated with worse OS, whereas treatment modality was not (RC: reference; PC: hazard ratio 0.94, [95% CI: 0.47-1.90], p=0.9). CONCLUSIONS: Upstaging of UCBD was frequent, indicating an inaccuracy in clinical staging. We found no differences in OS or MFS between PC and RC groups; therefore, PC may represent a feasible surgical alternative to RC in selected UCBD patients. PATIENT SUMMARY: In this report, we looked at the treatment of urothelial carcinoma arising in a bladder diverticulum (UCBD). We found that bladder-sparing treatment by partial cystectomy may be an alternative to radical cystectomy in carefully selected UCBD patients.

Pathogenic and targetable genetic alterations in 70 urachal adenocarcinomas.

Urachal cancer (UrC) is a rare but aggressive malignancy often diagnosed in advanced stages requiring systemic treatment. Although cytotoxic chemotherapy is of limited effectiveness, prospective clinical studies can hardly be conducted. Targeted therapeutic treatment approaches and potentially immunotherapy based on a biological rationale may provide an alternative strategy. We therefore subjected 70 urachal adenocarcinomas to targeted next-generation sequencing, conducted in situ and immunohistochemical analyses (including PD-L1 and DNA mismatch repair proteins [MMR]) and evaluated the microsatellite instability (MSI) status. The analytical findings were correlated with clinicopathological and outcome data and Kaplan-Meier and univariable/multivariable Cox regression analyses were performed. The patients had a mean age of 50 years, 66% were male and a 5-year overall survival (OS) of 58% and recurrence-free survival (RFS) of 45% was detected. Sequence variations were observed in TP53 (66%), KRAS (21%), BRAF (4%), PIK3CA (4%), FGFR1 (1%), MET (1%), NRAS (1%), and PDGFRA (1%). Gene amplifications were found in EGFR (5%), ERBB2 (2%), and MET (2%). We detected no evidence of MMR-deficiency (MMR-d)/MSI-high (MSI-h), whereas 10 of 63 cases (16%) expressed PD-L1. Therefore, anti-PD-1/PD-L1 immunotherapy approaches might be tested in UrC. Importantly, we found aberrations in intracellular signal transduction pathways (RAS/RAF/PI3K) in 31% of UrCs with potential implications for anti-EGFR therapy. Less frequent potentially actionable genetic alterations were additionally detected in ERBB2 (HER2), MET, FGFR1, and PDGFRA. The molecular profile strengthens the notion that UrC is a distinct entity on the genomic level with closer resemblance to colorectal than to bladder cancer.