Inverted Urothelial Papilloma Research Articles

Abstract 5312: Next generation quantitative proteomic analysis of urothelial lesions reveals novel diagnostic biomarkers to distinguish pathologic pitfalls and protein-protein interactions

Abstract There are several unmet needs remained to be solved in bladder urothelial lesions. Especially, the molecular biology of inverted urothelial papilloma (IUP) as a precursor disease of urothelial carcinoma is poorly understood. Also, muscle-invasive urothelial carcinoma (MIUC) of the bladder, showing a highly aggressive tumor behavior, has prompted the quest for robust biomarkers associated with invasion. A total of 265 tissue specimens from urinary bladder were enrolled for proteomic analysis and validation. Candidate biomarkers were selected through bioinformatic analysis, followed by validation. The latter comprised 2D and 3D invasion and migration assays, also a selection of external public datasets to evaluate mRNA expression and an in-house patient-derived tissue microarray (TMA) cohort to evaluate protein expression with immunohistochemistry (IHC). From the overall proteomic landscape, we found divergent ‘NU-like’ (low-risk) and ‘PUC-like’ (high-risk) signatures in IUP. The latter were characterized by altered metabolism, biosynthesis, and cell-cell interaction functions, indicating oncologic significance. Further machine learning-based analysis revealed SERPINH1, PKP2, and PYGB as potential diagnostic biomarkers discriminating IUP from PUC. The immunohistochemical validation confirmed PYGB as a specific biomarker to distinguish between IUP and PUC with inverted growth. For biomarkers predicting invasion, our multilayered platform-based analysis identified tubulin beta 6 class V (TUBB6) as a promising prognostic biomarker predicting MIUC of the bladder. The in vitro 2D and 3D migration and invasion assays consistently showed that inhibition of TUBB6 mRNA significantly reduced cell migration and invasion ability in two BUC cell lines with aggressive phenotype (TUBB6 migration, P = .0509 and P < .0001; invasion, P = .0002 and P = .0044; TGFBI migration, P = .0214 and P = .0026; invasion, P < .0001 and P = .0001; T24 and J82, respectively). Validation through multiple public datasets, including The Cancer Genome Atlas (TCGA) and selected GSE (Genomic Spatial Event) databases, confirmed TUBB6 as a potential biomarker predicting MIUC. Further protein-based validation with our TMA cohort revealed concordant results, highlighting the clinical implication of TUBB6 expression in BUC patients (overall survival: P < .001). We propose PYGB and TUBB6 as a novel IHC biomarker to predict IUP diagnosis or invasion and poor prognosis in routine practice, also select the optimal treatment in BUC patients. Citation Format: Han Suk Ryu, Soo Young Park, Da Sol Kim, Cheng Hyun Lee. Next generation quantitative proteomic analysis of urothelial lesions reveals novel diagnostic biomarkers to distinguish pathologic pitfalls and protein-protein interactions. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5312.

Proteomic-Based Machine Learning Analysis Reveals PYGB as a Novel Immunohistochemical Biomarker to Distinguish Inverted Urothelial Papilloma From Low-Grade Papillary Urothelial Carcinoma With Inverted Growth.

BackgroundThe molecular biology of inverted urothelial papilloma (IUP) as a precursor disease of urothelial carcinoma is poorly understood. Furthermore, the overlapping histology between IUP and papillary urothelial carcinoma (PUC) with inverted growth is a diagnostic pitfall leading to frequent misdiagnoses.MethodsTo identify the oncologic significance of IUP and discover a novel biomarker for its diagnosis, we employed mass spectrometry-based proteomic analysis of IUP, PUC, and normal urothelium (NU). Machine learning analysis shortlisted candidate proteins, while subsequent immunohistochemical validation was performed in an independent sample cohort.ResultsFrom the overall proteomic landscape, we found divergent ‘NU-like’ (low-risk) and ‘PUC-like’ (high-risk) signatures in IUP. The latter were characterized by altered metabolism, biosynthesis, and cell–cell interaction functions, indicating oncologic significance. Further machine learning-based analysis revealed SERPINH1, PKP2, and PYGB as potential diagnostic biomarkers discriminating IUP from PUC. The immunohistochemical validation confirmed PYGB as a specific biomarker to distinguish between IUP and PUC with inverted growth.ConclusionIn conclusion, we suggest PYGB as a promising immunohistochemical marker for IUP diagnosis in routine practice.

Machine Learning Based Classification from Whole-Slide Histopathological Images Enables Reliable and Interpretable Diagnosis of Inverted Urothelial Papilloma

Inverted urothelial papilloma (IUP) is a benign neoplasm of the urinary tract that accounts for less than 1% of urothelial tumors. It is diagnostically challenging for pathologists to distinguish histological features of IUP from other subtypes of non-invasive urothelial carcinoma, such as inverted Ta urothelial carcinoma (UCInv) and low-grade Ta urothelial carcinoma (UCLG). Using a machine learning approach, we analyzed the H&E-stained whole-slide histopathological images of 64 IUP (the largest cohort to date), 69 UCInv, and 92 UCLG samples, and propose a reliable, reproducible, and interpretable machine learning pipeline to classify IUP from other non-invasive urothelial carcinomas. The results showed that our method could achieve area under the ROC of 0.913 and 0.920 for classifying IUP from UCInv and UCLG, respectively, which is superior to competing methods, including deep learning-based methods. Testing of the classification models on an external validation dataset confirmed that our model can effectively identify IUP with high accuracy. Our results suggest that the proposed machine learning pipeline can robustly and accurately capture histopathological differences between IUP and other urothelial carcinoma subtypes, which can be extended to identify other rare cancer subtypes with limited samples and has the potential to expand the clinician’s armamentarium for accurate diagnosis. Funding: This work was supported in part by Indiana Precision Health Initiative to Kun Huang and Jie Zhang. Declaration of Interest: None to declare. Ethical Approval: This research was approved by the Institutional Review Boards of participating institutions.

Distinct mutational landscape of inverted urothelial papilloma.

A recent study has identified gene mutations involving the MAPK/ERK pathway, particularly the HRAS gene, in all inverted urothelial papillomas (IUPs), in the absence of pathway mutations in TERT promoter, FGFR3, and TP53/RB1genes. Neither recurrence nor progression was observed in IUPs. These data support several longstanding hypotheses: (1) IUPs are benign and do not recur or progress; (2) they harbor mutations that are different from those of urothelial carcinoma; and (3) they arise through different molecular mechanisms than low- or high-grade urothelial carcinoma. As the most critical differential diagnosis in this context is inverted-type urothelial carcinoma, more comprehensive studies are needed to compare and contrast these entities. © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Genomic landscape of inverted urothelial papilloma and urothelial papilloma of the bladder.

Inverted urothelial papilloma (IUP) and urothelial papilloma (UP) are rare urothelial neoplasms that typically follow a benign clinical course. Oncogenic mutations in FGFR3, HRAS, and the TERT promoter have been reported in these entities but no comprehensive molecular analysis has been performed. We sought to characterize the genomic landscape of IUP and UP using whole-exome and targeted next-generation sequencing. In IUP, 10 of 11 tumors harbored oncogenic hotspot mutations in HRAS and the remaining tumor had an oncogenic KRAS mutation. None of the IUP tumors harbored TERT promoter or FGFR3 mutations. In UP, 8 of 11 tumors had oncogenic KRAS mutations and two had oncogenic HRAS mutations. One UP tumor had oncogenic mutations in FGFR3, PIK3CA, and the TERT promoter, and arose in a patient with recurrent non-invasive papillary urothelial carcinomas. In contrast to urothelial carcinoma, the APOBEC mutational signature was not present in any IUP and UP tumors, and oncogenic alterations in chromatin remodeling genes were uncommon in both IUP and UP. The current study suggests that IUP and UP are driven primarily by RAS pathway activation and lack the more common genomic features of urothelial cancers. Copyright © 2019 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Inverted urothelial papilloma: A review of diagnostic pitfalls and clinical management.

Inverted urothelial papilloma (IUP) is a rare, non-invasive endophytic lesion that accounts for 1-2% of urothelial tumours. On cystoscopy, IUP appears as a pedunculated/papillary mass with a smooth surface. On microscopy, IUP has an endophytic growth pattern with the bulk of the tumour covered by a superficial layer of urothelium, which can be hyperplastic or attenuated. The cytology should be bland, with uniform, spindled cells arranged in anastomosing trabeculae and cords with peripheral palisading of basaloid cells. Exophytic papillae and mitotic activity should be absent or focal. Pseudoglandular spaces and squamous metaplasia may also be present. There are distinct molecular differences between IUP and urothelial carcinoma (UC). IUP rarely has mutations of FGFR3, homozygous loss of 9p21, or gain of chromosomes 3, 7, and 17, whereas these mutations are frequently seen in UC. In addition, IUP is much less likely to have TERT mutations compared to UC. Immunohistochemistry can also be helpful in distinguishing the two entities as IUP is typically negative for CK20 and has a low Ki-67 proliferation index. Positivity for p53 may be seen in a minority of IUP. IUP can recur and be seen in association with UC. Distinguishing IUP from UC can be difficult due to the similarity between the two entities both on cystoscopy and histology, as up to 25% of UCs will also have inverted growth. Given the morphologic variants of IUP and UC, it is possible for a diagnostic error to occur, which can significantly impact patient management.

Mechanical Implantation of Urothelium Into Periureteral Soft Tissue: A Series of 4 Cases Mimicking High-stage Urothelial Carcinoma.

In the upper genitourinary tract of the ureter and renal pelvis, any invasion of urothelial carcinoma (UC) beyond the thin muscularis is considered pT3 disease, which may prompt adjuvant chemotherapy. Ureteroscopy is commonly used in the workup of these lesions to obtain tissue biopsies and cytology specimens, or to place stents for the relief of obstructive symptoms. The current study describes 4 cases in which the presence of small nests of urothelium in periureteral and peripelvic soft tissue was noted after ureteroscopic instrumentation, mimicking high-stage UC. All 4 cases had a history of ureteral instrumentation with biopsy of the suspected UC. The diagnostic biopsies showed low-grade noninvasive papillary UC (n=2), papillary urothelial neoplasm of uncertain malignant potential (n=1), and benign inverted urothelial papilloma (n=1). In the definitive resection specimens, small nests of bland urothelium were present in the periureteral or peripelvic soft tissue, raising the possibility of pT3 UC. We interpreted these displaced small nests to be the result of mechanical implantation occurring during the ureteroscopic procedure on the basis of the finding of associated linear fibrosis, inflammation, hemorrhage, and foreign body giant cells. In the setting of low-grade or benign urothelial neoplasms in the upper urinary tract, caution is warranted when cytologically bland nests of the urothelium are identified beyond the muscularis that could represent mechanically induced implants as opposed to invasive UC extending into peripelvic or periureteral soft tissue.

MRI Findings of Inverted Urothelial Papilloma of the Bladder.

The objective of this study was to characterize MRI findings of inverted urothelial papilloma of the bladder. Data pertaining to 16 patients with 18 pathologically proven inverted urothelial papillomas of the bladder who had undergone MRI were retrospectively collected from seven institutions. The shape and surface characteristics of the tumors were evaluated using T2-weighted MR images. In addition, the signal intensity of inverted urothelial papillomas was visually assessed on T1-weighted, T2-weighted, and DW images and on early and delayed phase contrast-enhanced images. The shape of the 18 inverted urothelial papillomas of the bladder was classified as polypoid with a stalk for 16 tumors (89%) and polypoid without a stalk for two tumors (11%). All stalks were surrounded by urine in the bladder. A total of 15 of the tumor surfaces (83%) were nonpapillary and three (17%) were papillary. All 12 of the inverted urothelial papillomas for which evaluable T1-weighted images were available were isointense with the bladder wall. The lesions had a slightly higher signal intensity than the bladder wall in 15 of the patients (83%) and showed isointensity with the bladder wall in three patients (17%). A total of three patients (17%) had tiny hyperintense foci noted on T2-weighted images. All 16 of the inverted urothelial papillomas examined by DWI had very high signal intensity. All 13 of the lesions for which early phase images were obtained using dynamic contrast-enhanced MRI showed strong enhancement. When compared with early phase images, delayed phase images of the same 13 lesions showed that enhancement was stronger in two lesions (15%), similar in six lesions (46%), and weaker in five lesions (38%). On MRI, the typical appearance of inverted urothelial papillomas of the bladder is a polypoid shape with a nonpapillary surface and a thin short stalk surrounded by urine. Cystic foci are also occasionally seen within the tumor.

Immunohistochemistry and Fluorescence In Situ Hybridization Can Inform the Differential Diagnosis of Low-Grade Noninvasive Urothelial Carcinoma with an Inverted Growth Pattern and Inverted Urothelial Papilloma.

Urothelial carcinoma (UC) comprises a heterogeneous group of epithelial neoplasms with diverse biological behaviors and variable clinical outcomes. Distinguishing UC histological subtypes has become increasingly important because prognoses and therapy can dramatically differ among subtypes. In clinical work, overlapping morphological findings between low-grade noninvasive UC (LGNUC), which exhibits an inverted growth pattern, and inverted urothelial papilloma (IUP) can make subclassification difficult. We propose a combination of immunohistochemistry (IHC) and molecular cytogenetics for subtyping these clinical entities. In our study, tissue microarray immunohistochemical profiles of Ki-67, p53, cytokeratin 20 (CK20) and cyclinD1 were assessed. Molecular genetic alterations such as the gain of chromosomes 3, 7 or 17 or the homozygous loss of 9p21 were also assessed for their usefulness in differentiating these conditions. Based on our analysis, Ki-67 and CK20 may be useful for the differential diagnosis of these two tumor types. Fluorescence in situ hybridization (FISH) can also provide important data in cases in which the malignant nature of an inverted urothelial neoplasm is unclear. LGNUC with an inverted growth pattern that is negative for both Ki-67 and CK20 can be positively detected using FISH.

HRAS mutations are frequent in inverted urothelial neoplasms.

Inverted urothelial papilloma (IUP) is an uncommon neoplasm of the urinary bladder with distinct morphologic features. Studies regarding the role of human papillomavirus (HPV) in the etiology of IUP have provided conflicting evidence of HPV infection. In addition, little is known regarding the molecular alterations present in IUP or other urothelial neoplasms, which might demonstrate inverted growth pattern like low-grade or high-grade urothelial carcinoma (UCA). Here, we evaluated for the presence of common driving somatic mutations and HPV within a cohort of IUPs, (n = 7) noninvasive low-grade papillary UCAs with inverted growth pattern (n = 5), and noninvasive high-grade papillary UCAs with inverted growth pattern (n = 8). HPV was not detected in any case of IUP or inverted UCA by either in situ hybridization or by polymerase chain reaction. Next-generation sequencing identified recurrent mutations in HRAS (Q61R) in 3 of 5 IUPs, described for the first time in this neoplasm. Additional mutations of Ras pathway members were detected including HRAS, KRAS, and BRAF. The presence of Ras pathway member mutations at a relatively high rate suggests this pathway may contribute to pathogenesis of inverted urothelial neoplasms. In addition, we did not find any evidence supporting a role for HPV in the etiology of IUP.

A Case Report of an Inverted Papilloma of the Prostatic Urethra and a Synchronous Low-Grade Papillary Carcinoma of the Bladder

Inverted urothelial papilloma is a rare benign tumour and represents one of the urothelial lesions with inverted morphology. Accurate diagnosis and differentiation from other inverted lesions is important because its proper clinical management and expected clinical outcomes are distinctly different. Here we describe a case of a large inverted urothelial papilloma of the prostatic urethra and a synchronous non-invasive low-grade papillary urothelial carcinoma of the bladder in a 60-year-old man. We focus on the differential diagnosis of inverted urothelial papilloma.

Incidentally Discovered Inverted Papilloma of the Urinary Bladder in Patients with Lower Urinary Tract Symptoms

Inverted urothelial papilloma (IP) is an uncommon urothelial neoplasm. We aimed to determine the clinicopathologic characteristics of IP of the bladder and its association with prostate volume and lower urinary tract symptoms (LUTS). From 1994 to 2008, 53 patients with urinary IP underwent transurethral resection of the bladder tumor (TURBT) at our institution. We reviewed the clinicopathologic characteristics of IP of the bladder and its association with prostate volume and LUTS. The patient population consisted of 46 men and 7 women with a mean age of 56 years (male to female ratio 6.6:1). The most common presenting symptom was LUTS (33 men and 3 women). Of the 33 men with LUTS, the mean prostate volume before TURBT was 48.1 cc (range 21.8-109.3 cc). IP was found incidentally in 14 men on transrectal ultrasonography (TRUS) and in 2 men during transurethral prostate resection. In IP located on the bladder neck of patients with benign prostatic hyperplasia (BPH), significantly higher obstructive symptoms and larger prostate volumes than that of other located IP with BPH were observed. This is the largest series of cases of urinary bladder IP reported from Korea. Despite the absence of agreement of its etiology, its presenting symptoms were related to LUTS and benign prostatic enlargement. TRUS may be helpful, especially in unresponsive patients with LUTS despite medical treatment.

Inverted urothelial papilloma: is ploidy, MIB-1 proliferative activity, or p53 protein accumulation predictive of urothelial carcinoma?

Inverted urothelial papilloma is an unusual neoplasm of the urinary tract. Although the association between inverted urothelial papilloma and urothelial carcinoma is not entirely clear, many studies indicate that patients with inverted papilloma are at increased risk for the development of urothelial carcinoma. In addition, aneuploid inverted papillomas have been associated with the subsequent development of urothelial carcinoma. The objective of this study was to determine whether ploidy, MIB-1 proliferative activity, or p53 protein staining in inverted papilloma were predictive of urothelial carcinoma. Fifty-one cases of inverted papilloma were retrieved from the Tissue Registry of the Mayo Clinic. Clinical records were reviewed for patient age, length of follow-up, and history of urothelial carcinoma (defined as carcinoma prior to, concurrent with, or subsequent to the diagnosis of inverted papilloma). DNA ploidy analysis was determined using Feulgen stained sections from paraffin embedded tissues using an image analysis system. Quantitation of MIB-1 proliferative activity and p53 immunostaining was determined similarly using immunoperoxidase stained sections from paraffin embedded tissues. The mean age at diagnosis of inverted papilloma was 63.9 years (range, 37-87 years), and there were 39 men and 12 women. Patients were followed for a mean of 56.5 months (range, 1-252 months). Tumors ranged in size from 0.2 to 4.3 cm (mean, 0.9 cm). Eight patients (15.7%) had a prior, concurrent, or subsequent noninvasive World Health Organization and International Society of Urologic Pathology (WHO/ISUP) papillary neoplasm of low malignant potential or papillary carcinoma of low grade (formerly WHO Grade 1 or 2 papillary urothelial carcinoma). Inverted papillomas in patients with a history of urothelial carcinoma were all diploid and had a mean MIB-1 activity of 6.3% (range, 0.04-24.8%) and mean p53 protein staining of 12.6% (range, 0.5-24.9%). These inverted papillomas ranged in size from 0.3 to 1.0 cm (mean, 0.5 cm). Inverted papillomas in patients without a history of urothelial carcinoma were aneuploid in 6 cases (14.3%) and diploid in the remaining cases. These inverted papillomas had a mean MIB-1 activity of 1.6% (range, 0.06-9.0%) and mean p53 protein staining of 9.7% (range, 0.05-38.0%). Tumor size ranged from 0.2 to 4.3 cm (mean, 1.0 cm). There were no statistically significant differences in MIB-1 activity, p53 protein staining, ploidy, and morphologic features between inverted papillomas in patients with and without a history of urothelial carcinoma. Ploidy, MIB-1 proliferative activity, and p53 immunostaining in inverted urothelial papilloma were not useful in identifying patients who had a history of urothelial carcinoma.