Are We Ready to Implement Molecular Subtyping of Bladder Cancer in Clinical Practice? Part 1: General Issues and Marker Expression

Prognostic impact of EGFR expression and immunohistochemistry-based "molecular classification" in bladder cancer

Recent genomic studies emphasize the necessity of molecular classification to reflect diverse clinical and pathological characteristics of bladder cancer. Immunohistochemically bladder cancer can be classified into molecular subtypes, including basal, luminal, and p53-like subtypes. Epidermal growth factor receptor (EGFR) is frequently expressed in basal-type bladder cancers and is associated with poor prognosis. In our study, 88 urothelial carcinoma cases were retrospectively analyzed, molecularly subtyped using CK5/6, GATA3, p16 immunohistochemistry and examined for EGFR expressions as well as clinical and histopathological features. Tumor cell scores ≥20 % considered positive, classifying cases as luminal (GATA3-positive), basal (CK5/6-positive), double-positive (both-positive), or double-negative (both-negative). Further division of luminal and basal cases was based on p16 status: luminal-p53 or basal-p53 (p16-positive) and luminal-non-p53 or basal-non-p53 (p16-negative). Among the cases, 4 (4 %) were double-negative, 48 (55 %) luminal-non-p53, 21 (24 %) luminal-p53, 5 (6 %) basal-non-p53, 3 (3 %) basal-p53, and 7 (8 %) double-positive. Our findings revealed that basal-non-p53 type bladder cancer is associated with poor prognosis, muscle invasion, and high-grade cytology. Basal-p53 and double-negative types exhibited less aggressive features compared to basal-non-p53 types, with associations observed with lamina propria invasion and high-grade cytology. Luminal-p53 type demonstrated higher recurrence rates. Luminal-non-p53 type displayed the least aggressive characteristics, often associated with papillary histopathology. EGFR expression was found to be high in basal-non-p53 type and was further correlated with adverse prognostic indicators, lamina propria invasion, and high-grade cytology. The identification of molecular subtypes and EGFR expression through immunohistochemistry, alongside traditional bladder cancer classifications, enhances tumor behavior prediction and supports effective clinical management.

Contemporary Molecular Markers for Predicting Systemic Treatment Response in Urothelial Bladder Cancer: A Narrative Review

The search for dependable molecular biomarkers to enhance routine clinical practice is a compelling challenge across all oncology fields. Urothelial bladder carcinoma, known for its significant heterogeneity, presents difficulties in predicting responses to systemic therapies and outcomes post-radical cystectomy. Recent advancements in molecular cancer biology offer promising avenues to understand the disease's biology and identify emerging predictive biomarkers. Stratifying patients based on their recurrence risk post-curative treatment or predicting the efficacy of conventional and targeted therapies could catalyze personalized treatment selection and disease surveillance. Despite progress, reliable molecular biomarkers to forecast responses to systemic agents, in neoadjuvant, adjuvant, or palliative treatment settings, are still lacking, underscoring an urgent unmet need. This review aims to delve into the utilization of current and emerging molecular signatures across various stages of urothelial bladder carcinoma to predict responses to systemic therapy.

Prognostic Value of P63 Expression in Muscle-Invasive Bladder Cancer and Association with Molecular Subtypes-Preliminary Report

There is an ongoing need for biomarkers that could reliably predict the outcome of BC and that could guide the management of this disease. In this setting, we aimed to explore the prognostic value of the transcription factor P63 in patients with muscle-invasive bladder cancer (MIBC) having undergone radical cystectomy. The correlation between P63 expression and clinicopathological features (tumor stage, nodes involvement, patterns of muscularis propria invasion, papillary architecture, anaplasia, concomitant carcinoma in situ, lymphovascular invasion, perineural invasion, necrosis) and molecular subtyping (basal and luminal type tumors) was tested in 65 radical cystectomy specimens and matched with cancer-specific survival (CSS) and overall survival (OS). P63-negative tumors displayed significantly higher rates of pattern 2 of muscularis propria invasion (50% vs. 14%, p = 0.002) and variant histology (45% vs. 19%, p = 0.022) compared to P63-positive ones. According to the combined expression of CK5/6 and CK20 (Algorithm #1), P63-positive and P63-negative tumors were mostly basal-like and double-negative, respectively (p = 0.004). Using Algorithm #2, based on the combined expression of CK5/6 and GATA3, the vast majority of tumors were luminal overall and in each group (p = 0.003). There was no significant difference in CSS and OS between P63-positive and P63-negative tumors, but the former featured a trend towards longer OS. Though associated with pathological features harboring negative prognostic potential, P63 status as such failed to predict CSS and OS. That said, it may contribute to better molecular subtyping of MIBC.

Predicting individual outcomes after radical cystectomy in urothelial variants with Cancer of the Bladder Risk Assessment (COBRA) score

OBJECTIVE

To validate the Cancer of the Bladder Risk Assessment (COBRA) score in patients with urothelial variants.

METHODS

Epidemiological, clinical, radiological, and anatomopathological data were collected from patients with urothelial carcinoma who underwent radical cystectomy at the Institute of Cancer of São Paulo between May 2008 and December 2022. Patients with the presence of at least 10% of any urothelial variants in the radical cystectomy specimens' anatomopathological exam were included in the study. The COBRA score and derivatives were applied and correlated with oncological outcomes.

RESULTS

A total of 680 patients [482 men (70.9%) and 198 women (29.1%)]; 66 years (IQR 59-73) underwent radical cystectomy for bladder tumor, and of these patients, a total of 167 patients presented any type of urothelial variant. The median follow-up time was 28.77 months (IQR 12-85). The three most prevalent UV were squamous differentiation (50.8%), glandular differentiation (31.3%), and micropapillary differentiation (11.3%). The subtypes with the worst prognosis were sarcomatoid with a median survival of 8 months (HR 1.161; 95% CI 0.555-2.432) and plasmacytoid with 14 months (HR 1.466; 95% CI 0.528-4.070). The COBRA score for patients with micropapillary variants demonstrated good predictive accuracy for OS (log-rank P = 0.009; 95% IC 6.78-29.21) and CSS (log-rank P = 0.002; 95% IC 13.06-26.93).

CONCLUSIONS

In our study, the COBRA score proved an effective risk stratification tool for urothelial histological variants, especially for the micropapillary urothelial variant. It may be helpful in the prognosis evaluation of UV patients after radical cystectomy.

Androgen Insensitivity Syndrome with Bilateral Gonadal Sertoli Cell Lesions, Sertoli-Leydig Cell Tumor, and Paratesticular Leiomyoma: A Case Report and First Systematic Literature Review

Androgen insensitivity syndrome (AIS) is a rare Mendelian disorder caused by mutations of the androgen receptor (AR) gene on the long arm of the X chromosome. As a result of the mutation, the receptor becomes resistant to androgens, and hence, karyotypically male patients (46,XY) carry a female phenotype. Their cryptorchid gonads are prone to the development of several types of tumors (germ cell, sex cord stromal, and others). Here, we report a 15-year-old female-looking patient with primary amenorrhea who underwent laparoscopic gonadectomy. Histologically, the patient's gonads showed Sertoli cell hamartomas (SCHs) and adenomas (SCAs) with areas of Sertoli-Leydig cell tumors (SLCTs) and a left-sided paratesticular leiomyoma. Rudimentary Fallopian tubes were also present. The patient's karyotype was 46,XY without any evidence of aberrations. Molecular genetic analysis of the left gonad revealed two likely germline mutations-a pathogenic frameshift deletion in the AR gene (c.77delT) and a likely pathogenic missense variant in the RAC1 gene (p.A94V). Strikingly, no somatic mutations, fusions, or copy number variations were found. We also performed the first systematic literature review (PRISMA guidelines; screened databases: PubMed, Scopus, Web of Science; ended on 7 December 2023) of the reported cases of patients with AIS showing benign or malignant Sertoli cell lesions/tumors in their gonads (n = 225; age: 4-84, mean 32 years), including Sertoli cell hyperplasia (1%), Sertoli cell nodules (6%), SCHs (31%), SCAs (36%), Sertoli cell tumors (SCTs) (16%), and SLCTs (4%). The few cases (n = 14, 6%; six SCAs, four SCTs, two SLCTs, and two SCHs) with available follow-up (2-49, mean 17 months) showed no evidence of disease (13/14, 93%) or died of other causes (1/14, 7%) despite the histological diagnosis. Smooth muscle lesions/proliferations were identified in 19 (8%) cases (including clearly reported rudimentary uterine remnants, 3 cases; leiomyomas, 4 cases). Rudimentary Fallopian tube(s) were described in nine (4%) cases. Conclusion: AIS may be associated with sex cord/stromal tumors and, rarely, mesenchymal tumors such as leiomyomas. True malignant sex cord tumors can arise in these patients. Larger series with longer follow-ups are needed to estimate the exact prognostic relevance of tumor histology in AIS.

Development of a butyrate metabolism-related gene-based molecular subtypes and scoring system for predicting prognosis and immunotherapy response in bladder cancer

PURPOSE

In recent times, multiple molecular subtypes with varying prognoses have been identified in bladder cancer (BLCA). However, the attributes of butyrate metabolism-related (BMR) molecular subtypes and their correlation with immunotherapy response remain inadequately explored in BLCA.

METHODS

We utilized 594 samples of BLCA to investigate the molecular subtypes mediated by BMR genes and their correlation with the immunotherapy response. To quantify the BMR features of individual tumors, we developed a BMR score through the COX and LASSO regression methods. Clinical-related, tumor microenvironment, drug-sensitive and immunotherapy analyses were used to comprehensively analyze BMR scores.

RESULTS

Two distinct molecular subtypes related to butyrate metabolism were identified in BLCA, each with unique prognostic implications and immune microenvironments. BMR score was constructed based on 7 BMR genes and was used to classify the patients into two score groups. Clinical analysis revealed that the BMR score was an independent prognostic factor. The higher the score, the worse the prognosis. The BMR score can also predict tumor immunity. The results demonstrated that a low BMR score was associated with higher efficacy of immunotherapy, which was also validated by an external dataset.

CONCLUSION

Our study proposes both molecular subtypes and a BMR-based score as promising prognostic classifications in BLCA. These findings may offer new insights for the development of precise targeted cancer therapies.

Risk Classification of Bladder Cancer by Gene Expression and Molecular Subtype

This study evaluated a panel including the molecular taxonomy subtype and the expression of 27 genes as a diagnostic tool to stratify bladder cancer patients at risk of aggressive behavior, using a well-characterized series of non-muscle invasive bladder cancer (NMIBC) as well as muscle-invasive bladder cancer (MIBC). The study was conducted using the novel NanoString nCounter gene expression analysis. This technology allowed us to identify the molecular subtype and to analyze the gene expression of 27 bladder-cancer-related genes selected through a recent literature search. The differential gene expression was correlated with clinicopathological variables, such as the molecular subtypes (luminal, basal, null/double negative), histological subtype (conventional urothelial carcinoma, or carcinoma with variant histology), clinical subtype (NMIBC and MIBC), tumor stage category (Ta, T1, and T2–4), tumor grade, PD-L1 expression (high vs. low expression), and clinical risk categories (low, intermediate, high and very high). The multivariate analysis of the 19 genes significant for cancer-specific survival in our cohort study series identified TP53 (p = 0.0001), CCND1 (p = 0.0001), MKI67 (p < 0.0001), and molecular subtype (p = 0.005) as independent predictors. A scoring system based on the molecular subtype and the gene expression signature of TP53, CCND1, or MKI67 was used for risk assessment. A score ranging from 0 (best prognosis) to 7 (worst prognosis) was obtained and used to stratify our patients into two (low [score 0–2] vs. high [score 3–7], model A) or three (low [score 0–2] vs. intermediate [score 3–4] vs. high [score 5–7], model B) risk categories with different survival characteristics. Mean cancer-specific survival was longer (122 + 2.7 months) in low-risk than intermediate-risk (79.4 + 9.4 months) or high-risk (6.2 + 0.9 months) categories (p < 0.0001; model A); and was longer (122 + 2.7 months) in low-risk than high-risk (58 + 8.3 months) (p < 0.0001; model B). In conclusion, the molecular risk assessment model, as reported here, might be used better to select the appropriate management for patients with bladder cancer.

Clinicopathological Features and Survival Analysis in Molecular Subtypes of Muscle-Invasive Bladder Cancer

Molecular subtyping of bladder cancer (BC) aims to capture the biological heterogeneity of this complex disease in order to provide better patient risk stratification. Immunohistochemical (IHC) markers are regarded as promising surrogates to classify BCs into luminal and basal subtypes in routine practice. We investigated the correlation between the molecular subclassification, assessed through IHC, and the conventional prognostic variables of a cohort of 93 muscle-invasive BCs (MIBCs), with a focus on the pattern of muscularis propria (MP) invasion, and evaluated their association with outcome. Basal, luminal, double-positive (DP), and double-negative (DN) phenotypes were identified according to the coordinate expression of 1 basal (CK5/6) and 2 luminal (CK20, GATA3) markers, and accounted for 33.3%, 32.3%, 3.2%, and 31.2% (Scheme #1) and 9.7%, 60.2%, 26.9%, and 3.2% (Scheme #2). There was a significant association between the pattern of MP invasion and the molecular subtypes according to Scheme #2, in that all 8 basal and DN cases, as well as 83% of DP cases, had a non-infiltrative invasion pattern. No consistent differences were observed in terms of OS and CSS between the molecular subtypes obtained through surrogate IHC markers. In keeping with previous studies, we report the correlation between the identification of BC subtypes and the presence of morphological prognostic factors, supporting the need for a comprehensive pathological evaluation, including clinicopathological and molecular parameters, in order to improve the diagnosis and management of MIBC.

HER2 Expression in Bladder Cancer: A Focused View on Its Diagnostic, Prognostic, and Predictive Role

Bladder cancer (BC) is a heterogeneous disease from a molecular, morphological, and clinical standpoint. HER2 is a known oncogene involved in bladder carcinogenesis. Assessing HER2 overexpression as a result of its molecular changes in a routine pathology practice using immunohistochemistry might be a useful adjunct in several scenarios, namely (1) to correctly identify flat urothelial lesions and inverted urothelial lesions in the diagnostic setting; (2) to provide prognostic hints in both non-muscle invasive (NMI) and muscle invasive (MI) tumors, thus supplementing risk stratification tools, especially when evaluating higher-risk tumors such as those with variant morphology; (3) to improve antibody panels as a surrogate marker of BC molecular subtyping. Furthermore, the potential of HER2 as a therapeutic target has been only partly explored so far, in light of the ongoing development of novel target therapies.