Differential NEUROD1, ASCL1, and POU2F3 Expression Defines Molecular Subsets of Bladder Small Cell/Neuroendocrine Carcinoma With Prognostic Implications.

Small cell carcinomas (SMC) of the lung are now molecularly classified based on the expression of transcriptional regulators (NEUROD1, ASCL1, POU2F3, and YAP1) and DLL3, which has emerged as an investigational therapeutic target. PLCG2 has been shown to identify a distinct subpopulation of lung SMC with stem cell-like and prometastasis features and poor prognosis. We analyzed the expression of these novel neuroendocrine markers and their association with traditional neuroendocrine markers and patient outcomes in a cohort of bladder neuroendocrine carcinoma (NEC) consisting of 103 SMC and 19 large cell NEC (LCNEC) assembled in tissue microarrays. Coexpression patterns were assessed and integrated with detailed clinical annotation including overall (OS) and recurrence-free survival (RFS) and response to neoadjuvant/adjuvant chemotherapy. We identified 5 distinct molecular subtypes in bladder SMC based on the expression of ASCL1, NEUROD1, and POU2F3: ASCL1+/NEUROD1- (n = 33; 34%), ASCL1- /NEUROD1+ (n = 21; 21%), ASCL1+/NEUROD1+ (n = 17; 17%), POU2F3+ (n = 22, 22%), and ASCL1- /NEUROD1- /POU2F3- (n = 5, 5%). POU2F3+ tumors were mutually exclusive with those expressing ASCL1 and NEUROD1 and exhibited lower expression of traditional neuroendocrine markers. PLCG2 expression was noted in 33 tumors (32%) and was highly correlated with POU2F3 expression (P < .001). DLL3 expression was high in both SMC (n = 72, 82%) and LCNEC (n = 11, 85%). YAP1 expression was enriched in nonneuroendocrine components and negatively correlated with all neuroendocrine markers. In patients without metastatic disease who underwent radical cystectomy, PLCG2+ or POU2F3+ tumors had shorter RFS and OS (P < .05), but their expression was not associated with metastasis status or response to neoadjuvant/adjuvant chemotherapy. In conclusion, the NEC of the bladder can be divided into distinct molecular subtypes based on the expression of ASCL1, NEUROD1, and POU2F3. POU2F3-expressing tumors represent an ASCL1/NEUROD1-negative subset of bladder NEC characterized by lower expression of traditional neuroendocrine markers. Marker expression patterns were similar in SMC and LCNEC. Expression of PLCG2 and POU2F3 was associated with shorter RFS and OS. DLL3 was expressed at high levels in both SMC and LCNEC of the bladder, nominating it as a potential therapeutic target.

Updates on Urinary Bladder Tumors With Neuroendocrine Features.

The most common neuroendocrine tumor in the urinary bladder is small cell carcinoma, which can be pure or mixed with components of urothelial or other histologic subtypes. Large cell neuroendocrine carcinoma of the bladder is rare and remains ill-defined but is increasingly recognized. Well-differentiated neuroendocrine tumor and paraganglioma can arise in the bladder but are very rare in this location. Recent advances in molecular characterization allowed for better classification and may offer improved stratification of these tumors.

Molecular Alterations Associated with Histologically Overt Stromal Response in Patients with Prostate Cancer.

Prostate cancer has substantial heterogeneity in clinical outcomes and therapeutic responses, posing challenges in predicting disease progression and tailoring treatment strategies. Recent studies have highlighted the potential prognostic value of evaluating the tumor microenvironment, including the presence of a histologically overt stromal response (HOST-response) characterized by peri-glandular stromal changes and architectural distortions. This retrospective study examined patient records from The Cancer Genome Atlas database to identify genomic alterations associated with the HOST-response in prostate cancer. Among 348 patients who underwent radical prostatectomy, 160 (45.98%) were identified as having a HOST-response. A gene expression analysis revealed 1263 genes with significantly higher expression in patients with a HOST-response. A protein-protein interaction network analysis identified seven hub genes (KIF2C, CENPA, CDC20, UBE2C, ESPL1, KIF23, and PLK1) highly interconnected in the network. A functional enrichment analysis revealed alterations in the cell division, cytoskeletal organization, cytokinesis, and interleukin-16 signaling pathways in patients with a HOST-response, suggesting dysregulated proliferation and inflammation. The distinct molecular signature associated with the HOST-response provides insights into the tumor-stroma interactions driving adverse outcomes and potential targets for tailored therapeutic interventions in this subset of patients with prostate cancer.

Are Renal Tumor Diagnostics Becoming Too Advanced for Many Pathology Laboratories?

The recent influx of novel renal neoplasms, particularly molecularly-defined renal carcinomas, has introduced new challenges in the daily practice of most pathology laboratories. These tumors are uncommon, they do not always have well-established morphologic features, and the expression profile of most common biomarkers is not well understood. Moreover, the diagnosis of molecularly-defined renal carcinomas requires the documentation of the disease-defining molecular alteration, with molecular studies or surrogate immunohistochemical markers. Unfortunately, most pathology laboratories lack molecular laboratories, or it is not cost-effective to maintain assays of the specific biomarkers in these unusual tumors. Pathologists should have updated knowledge about the recent changes in renal neoplasms and be aware of these limitations.

Prognostic Significance of the Cribriform Pattern in Prostate Cancer: Clinical Outcomes and Genomic Alterations.

PURPOSE: Given the diverse clinical progression of prostate cancer (PC) and the evolving significance of histopathological factors in its management, this study aimed to explore the impact of cribriform pattern 4 (CP4) on clinical outcomes in PC patients and examine its molecular characteristics. METHODS: This retrospective study analyzed data from The Cancer Genome Atlas (TCGA) database and included PC patients who underwent radical prostatectomy (RP) and had pathology slides available for the assessment of CP4. A multivariable competing risk regression analysis was used to assess the association between CP4 and progression-free survival (PFS) while adjusting for established PC prognostic factors. The frequency of genomic alterations was compared between patients with and without CP4 using the Fisher's exact test. RESULTS: Among the 394 patients analyzed, 129 (32.74%) had CP4. After a median follow-up of 40.50 months (IQR: 23.90, 65.60), the presence of CP4 was significantly associated with lower PFS (AHR, 1.84; 95% CI, 1.08 to 3.114; p = 0.023) after adjusting for covariates. Seven hub genes-KRT13, KRT5, KRT15, COL17A1, KRT14, KRT16, and TP63-had significantly lower mRNA expression levels in patients with CP4 compared to those without. CONCLUSIONS: PC patients with CP4 have distinct genomic alterations and are at a high risk of disease progression following RP. Therefore, these patients may benefit from additional post-RP treatments and should be the subject of a prospective randomized clinical trial.

Histologically Overt Stromal Response and the Risk of Progression after Radical Prostatectomy for Prostate Cancer.

PURPOSE: Given the variable clinical course of prostate cancer and the limitations of current prognostic factors, this study was conducted to investigate the impact of a histologically overt stromal response (HOST-response) to prostate cancer on clinical outcomes after radical prostatectomy. METHODS: This retrospective analysis utilized The Cancer Genome Atlas (TCGA) to evaluate data from individuals with a confirmed diagnosis of prostate cancer who underwent radical prostatectomy and had available pathology slides. These slides were assessed for the presence of a HOST-response, similar to desmoplasia. The primary endpoint was progression-free survival (PFS). A multivariable competing risk regression analysis was used to assess whether a significant association existed between HOST-response and PFS, adjusting for known prostate cancer prognostic factors. RESULTS: Among the 348 patients analyzed, 166 (47.70%) demonstrated a HOST-response. After a median follow-up of 37.87 months (IQR: 21.20, 65.50), the presence of a HOST-response was significantly associated with a shorter PFS (SDHR, 2.10; 95% CI, 1.26 to 3.50; p = 0.004), after adjusting for covariates. CONCLUSIONS: HOST-response in prostate cancer patients treated with radical prostatectomy is significantly associated with reduced PFS, suggesting a potential benefit from adjuvant therapy and highlighting the need for further investigation in a prospective randomized clinical trial.

Mismatch repair deficiency and microsatellite instability in urothelial carcinoma: a systematic review and meta-analysis.

Background: Mismatch repair deficiency (dMMR) and microsatellite instability-high (MSI-H) occur in a subset of cancers and have been shown to confer sensitivity to immune checkpoint inhibition (ICI); however, there is a lack of prospective data in urothelial carcinoma (UC). Methods and analysis: We performed a systematic review to estimate the prevalence of dMMR and MSI-H in UC, including survival and clinical outcomes. We searched for studies published up to 26 October 2022 in major scientific databases. We screened 1745 studies and included 110. Meta-analyses were performed if the extracted data were suitable. Results: The pooled weighted prevalences of dMMR in bladder cancer (BC) and upper tract UC (UTUC) were 2.30% (95% CI 1.12% to 4.65%) and 8.95% (95% CI 6.81% to 11.67%), respectively. The pooled weighted prevalences of MSI-H in BC and UTUC were 2.11% (95% CI 0.82% to 5.31%) and 8.36% (95% CI 5.50% to 12.53%), respectively. Comparing localised versus metastatic disease, the pooled weighted prevalences for MSI-H in BC were 5.26% (95% CI 0.86% to 26.12%) and 0.86% (95% CI 0.59% to 1.25%), respectively; and in UTUC, they were 18.04% (95% CI 13.36% to 23.91%) and 4.96% (95% CI 2.72% to 8.86%), respectively. Cumulatively, the response rate in dMMR/MSI-H metastatic UC treated with an ICI was 22/34 (64.7%) compared with 1/9 (11.1%) with chemotherapy. Conclusion: Both dMMR and MSI-H occur more frequently in UTUC than in BC. In UC, MSI-H occurs more frequently in localised disease than in metastatic disease. These biomarkers may predict sensitivity to ICI in metastatic UC and resistance to cisplatin-based chemotherapy.

Final Results From a Phase I Trial and Expansion Cohorts of Cabozantinib and Nivolumab Alone or With Ipilimumab for Advanced/Metastatic Genitourinary Tumors.

PURPOSE: Cabozantinib and nivolumab (CaboNivo) alone or with ipilimumab (CaboNivoIpi) have shown promising efficacy and safety in patients with metastatic urothelial carcinoma (mUC), metastatic renal cell carcinoma (mRCC), and rare genitourinary (GU) tumors in a dose-escalation phase I study. We report the final data analysis of the safety, overall response rate (ORR), progression-free survival (PFS), and overall survival (OS) of the phase I patients and seven expansion cohorts. METHODS: This is an investigator-initiated, multicenter, phase I trial. CaboNivo doublet expansion cohorts included (1) mUC, (2) mRCC, and (3) adenocarcinoma of the bladder/urachal; CaboNivoIpi triplet expansion cohorts included (1) mUC, (2) mRCC, (3) penile cancer, and (4) squamous cell carcinoma of the bladder and other rare GU tumors (ClinicalTrials.gov identifier: NCT02496208). RESULTS: The study enrolled 120 patients treated with CaboNivo (n = 64) or CaboNivoIpi (n = 56), with a median follow-up of 49.2 months. In 108 evaluable patients (CaboNivo n = 59; CaboNivoIpi n = 49), the ORR was 38% (complete response rate 11%) and the median duration of response was 20 months. The ORR was 42.4% for mUC, 62.5% for mRCC (n = 16), 85.7% for squamous cell carcinoma of the bladder (n = 7), 44.4% for penile cancer (n = 9), and 50.0% for renal medullary carcinoma (n = 2). Grade ≥ 3 treatment-related adverse events occurred in 84% of CaboNivo patients and 80% of CaboNivoIpi patients. CONCLUSION: CaboNivo and CaboNivoIpi demonstrated clinical activity and safety in patients with multiple GU malignancies, especially clear cell RCC, urothelial carcinoma, and rare GU tumors such as squamous cell carcinoma of the bladder, small cell carcinoma of the bladder, adenocarcinoma of the bladder, renal medullary carcinoma, and penile cancer.

Protocol for isolation of signet ring cells from human gastric mucosa.

More than 90% of individuals with germline pathogenic CDH1 variants will harbor occult, microscopic foci of signet ring cell carcinomas capable of progressing to advanced diffuse-type gastric cancer. Here, we present a protocol for high viability suspension of signet ring cells from human gastric tissue. We describe the steps for gastric mucosa isolation and tissue dissociation. We then detail procedures for embedding cells into HistoGel for immunohistochemistry staining and additional applications such as flow cytometry and single-cell sequencing.

Capsular Invasion Matters Also in "Papillary Patterned" Tumors: A Study on 121 Cases of Encapsulated Conventional Variant of Papillary Thyroid Carcinoma.

Papillary thyroid carcinoma (PTC) is the most common type of thyroid malignancy. Some PTCs with classical papillae can be totally or partially encapsulated, and these tumors are called "encapsulated" (conventional) variant of papillary thyroid carcinoma. We aimed to investigate the clinicopathological features of this variant, comparing with non-encapsulated conventional type PTC. Among 823 thyroidectomy specimens with PTC diagnosed between 2015 and 2018, 121 tumors from 105 patients (12.75%) were reclassified as encapsulated conventional PTC. In 76 patients, tumors were unifocal. Size, cystic changes, background thyroiditis, psammoma bodies, cervical lymph node metastasis at presentation, capsular/vascular invasion, and immunohistochemical BRAF-V600E expression were evaluated. Ninety-two non-encapsulated conventional PTCs served as control group. Encapsulated cases were predominantly women (73.3%), 56.4% were microcarcinomas, 97.5% had cystic changes, 81.4% were BRAF-V600E positive, and 36.8% of unifocal encapsulated tumors had cervical lymph node metastasis. Thyroiditis and psammoma bodies were detected in nearly half of the encapsulated PTCs. Fourteen percent of the unifocal tumors showed total encapsulation, whereas capsular and vascular invasion was detected in 85.5% and 5.8%, respectively. Encapsulated cases did not show any significant difference from the control group, except for prominent cystic changes (p < 0.001). Relationship between lymph node metastasis at presentation and capsular invasion was statistically significant (p = 0.001), and metastasis was more frequent in cases with extensive capsular invasion (no/minimal invasion versus extensive invasion, p < 0.001). Cystic changes are very common, and this feature deserves mentioning as a morphological characteristic of encapsulated conventional PTCs. As in encapsulated "follicular" variant of PTC, capsular invasion status is important in evaluating papillary patterned encapsulated PTC for predicting lymph node metastasis. Total examination of the tumor capsule and inclusion of capsular invasion status in pathology reports are recommended.