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

Characterization of the stem cell landscape and identification of a stemness-associated prognostic signature in bladder cancer

It is accepted that cancer stem cells (CSCs) are key to the occurrence, progression, drug resistance, and recurrence of bladder cancer (BLCA). Here, we aimed to characterize the landscapes of CSCs and investigate the biological and clinical signatures based on a prognostic model constructed by genes associated with CSCs. The malignant epithelial cells were discovered and sorted into six clusters through single cell analysis. C2 was identified as the CSCs. The signaling involved in the interactions between C2, cancer-associated fibroblasts (CAFs), and immune cells mainly consisted of MK, THBS, ANGPTL, VISFATIN, JAM, and ncWNT pathways. The CSC-like prognostic index (CSCLPI) constructed by the random survival forest was a reliable risk factor for BLCA and had a stable and powerful effect on predicting the overall survival of patients with BLCA. The level of CAFs was higher among patients with higher CSCLPI scores, suggesting that CAFs play a significant role in regulating biological characteristics. The CSCLPI-developed survival prediction nomogram has the potential to be applied clinically to predict the 1-, 2-, 3-, and 5-year overall survival of patients with BLCA. The CSCLPI can be used for prognostic prediction and drug treatment evaluation in the clinic.

Immunohistochemistry Screening of Different Tyrosine Kinase Receptors in Canine Solid Tumors-Part I: Proposal of a Receptor Panel to Predict Therapies

The use of tyrosine kinase inhibitors (TKI) has been growing in veterinary oncology and in the past few years several TKI have been tested in dogs. However, different from human medicine, we lack strategies to select patients to be treated with each TKI. Therefore, this study aimed to screen different tumor subtypes regarding TKI target immunoexpression as a predictor strategy to personalize the canine cancer treatment. It included 18 prostatic carcinomas, 36 soft tissue sarcomas, 20 mammary gland tumors, 6 urothelial bladder carcinomas, and 7 tumors from the endocrine system. A total of 87 patients with paraffin blocks were used to perform immunohistochemistry (IHC) of human epidermal growth factor receptor 2 (HER-2), epidermal growth factor receptors 1 (EGFR1), vascular endothelial growth factor receptor 2 (VEGFR-2), platelet derived growth factor receptor beta (PDGFR-β), c-KIT, and extracellular signal-regulated kinase 1/2 (ERK1/ERK2). The immunohistochemical screening revealed a heterogeneous protein expression among histological types with mesenchymal tumors showing the lowest expression level and carcinomas the highest expression. We have demonstrated by IHC screening that HER2, EGFR1, VEGFR-2, PDGFR-β and ERK1/ERK2 are commonly overexpressed in dogs with different carcinomas, and KIT expression is considered relatively low in the analyzed samples.

Prognostic Significance of HER2 Expression in Patients with Bacillus Calmette-Guérin-exposed Non-muscle-invasive Bladder Cancer

BACKGROUND

Guidelines recommend intravesical instillation of bacillus Calmette-Guérin (BCG) as the first-choice treatment for intermediate- and high-risk non-muscle-invasive bladder cancer (NMIBC). However, there is no therapeutic biomarker for predicting BCG efficacy, especially in high-risk cases with high failure rates. HER2 expression is considered a prognostic factor for bladder cancer.

OBJECTIVE

To elucidate the predictive value and significance of HER2 expression in patients with BCG-exposed NMIBC.

DESIGN, SETTING, AND PARTICIPANTS

A total of 454 patients with NMIBC were included. All patients started BCG intravesical instillation (1.2 × 108 CFU, strain D2PB302) 2-6 wk after transurethral resection of bladder tumor and received 19 treatments over a period of 1 yr. HER2 immunohistochemistry (IHC) results available for 314 patients.

OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS

The outcomes investigated were recurrence-free survival (RFS) and progression-free survival (PFS). Outcome relationships were explored using multivariable Cox regression and log-rank analysis.

RESULTS AND LIMITATIONS

In the IHC population, 35.7% of patients had HER2 overexpression (IHC score 2/3+). This group had a poor 5-yr RFS rate of 16.5%, in comparison to 68.0% in the group with low HER2 expression (p < 0.001). Patients with high-risk NMIBC and HER2 overexpression had the highest risk of BCG treatment failure, with 5-yr RFS and PFS rates of 19.0% and 58.2%, respectively. Conversely, HER2-negative (IHC score 0) patients with high-risk NMIBC experienced a long-term BCG benefit, with 5-yr RFS and PFS rates of 80.8% and 92.1%, respectively. Limitations include the retrospective study design and the limited details regarding BCG use.

CONCLUSIONS

HER2 was an independent predictor of poor BCG efficacy in NMIBC. Patients with high-risk NMIBC and HER2 overexpression had the highest risk of disease recurrence and progression after exposure to BCG. Anti-HER2 targeted therapies could be considered for these patients.

PATIENT SUMMARY

Measurement of blood levels of the protein HER2 can be used to predict outcomes after BCG (bacillus Calmette-Guérin) bladder therapy for patients with intermediate- or high-risk non-muscle-invasive bladder cancer. Measurement results for HER2 may help in guiding personalized treatment for these patients.

Pharmacogenetics in Oncology: A useful tool for individualizing drug therapy

With the continuous development of genetics in healthcare, there has been a significant contribution to the development of precision medicine, which is ultimately aimed at improving the care of patients. Generally, drug treatments used in Oncology are characterized by a narrow therapeutic range and by their potential toxicity. Knowledge of pharmacogenomics and pharmacogenetics can be very useful in the area of Oncology, as they constitute additional tools that can help to individualize patients' treatment. This work includes a description of some genes that have been revealed to be useful in the field of Oncology, as they play a role in drug prescription and in the prediction of treatment response.

Antibody-Drug Conjugates in Urothelial Cancer: From Scientific Rationale to Clinical Development

Antibody-drug conjugates (ADCs) have been a significant advancement in cancer therapy, particularly for urothelial cancer (UC). These innovative treatments, originally developed for hematological malignancies, use target-specific monoclonal antibodies linked to potent cytotoxic agents. This rational drug design efficiently delivers cancer cell-killing agents to cells expressing specific surface proteins, which are abundant in UC owing to their high antigen expression. UC is an ideal candidate for ADC therapy, as it enhances on-target efficacy while mitigating systemic toxicity. In recent years, considerable progress has been made in understanding the biology and mechanisms of tumor progression in UC. However, despite the introduction of immune checkpoint inhibitors, advanced UC is characterized by rapid progression and poor survival rates. Targeted therapies that have been developed include the anti-nectin 4 ADC enfortumab vedotin and the fibroblast growth factor receptor inhibitor erdafitinib. Enfortumab vedotin has shown efficacy in prospective studies in patients with advanced UC, alone and in combination with pembrolizumab. The anti-Trop-2 ADC sacituzumab govitecan has also demonstrated effectiveness in single-armed studies. This review highlights the mechanism of action of ADCs, their application in mono- and combination therapies, primary mechanisms of resistance, and future perspectives for their clinical use in UC treatment. ADCs have proven to be an increasingly vital component of the therapeutic landscape for urothelial carcinoma, filling a gap in the treatment of this progressive disease.

Amide Proton Transfer-Weighted Imaging in Assessing the Aggressive and Proliferative Potential of Bladder Cancer

BACKGROUND

Ki-67 and human epidermal growth factor receptor 2 (HER2) are known oncogenes involved in bladder cancer (BCa) patient risk stratification. Preoperative assessment of their expression level can assist in clinical treatment decision-making. Recently, amide proton transfer-weighted (APTw) MRI has shown promising potential in the diagnosis of several malignancies. However, few studies reported the value of APTw imaging in evaluating Ki-67 and HER2 status of BCa.

PURPOSE

To investigate the feasibility of APTw MRI in assessing the aggressive and proliferative potential regarding the expression levels of Ki-67 and HER2 in BCa.

STUDY TYPE

Retrospective.

SUBJECTS

114 patients (mean age, 64.78 ± 11.93 [SD] years; 97 men) were studied.

FIELD STRENGTH/SEQUENCE

APTw MRI acquired by a three-dimensional fast-spin-echo sequence at 3.0 T MRI system.

ASSESSMENT

Patient pathologic findings, included histologic grade and the expression status of Ki-67 and HER2, were reviewed by one uropathologist. The APTw values of BCa were independently measured by two radiologists and were compared between high-/low-tumor grade group, high-/low-Ki-67 expression group, and high-/low-HER2 expression group.

STATISTICAL TESTS

The interclass correlation coefficient, independent sample t-test, Mann-Whitney U test, Spearman's rank correlation, and receiver operating characteristic curve (ROC) analysis were used. P < 0.05 was considered statistically significant.

RESULTS

Significantly higher APTw values were found in high-grade BCa patients (7.72% vs. 4.29%, P < 0.001), high-Ki-67 expression BCa patients (8.40% vs. 3.25%, P < 0.001) and HER2 positive BCa patients (8.24% vs. 5.40%, P = 0.001). APTw values were positively correlated with Ki-67 (r = 0.769) and HER2 (r = 0. 356) expression status. The area under the ROC curve of the APTw values for detecting Ki-67 and HER2 expression status were 0.883 (95% CI: 0.790-0.945) and 0.713 (95% CI: 0.592-0.816), respectively.

DATA CONCLUSIONS

APTw MRI is a potential method to assess the biological and proliferation potential of BCa.

LEVEL OF EVIDENCE: 4

TECHNICAL EFFICACY

Stage 2.

Frequency of next-generation sequencing, prevalence of targetable mutations and response to targeted therapies amongst patients with metastatic urothelial cancer in Ireland: a multi-centre retrospective study of real-world data

BACKGROUND

The genomic knowledge on urothelial carcinoma is expanding. It is recognised that urothelial carcinoma is a disease with a high somatic mutation rate and a high prevalence of genetic alterations, as discussed by Thomas and Sonpavde (2022). In the context of a disease rich with somatic alterations, continuing efforts to better identify which patients may benefit most from targeted therapy, immunotherapy and combination therapy may ultimately lead to improved outcomes for patients with this disease.

AIMS

We aimed to ascertain the frequency of next-generation sequencing (NGS) and the prevalence of genomic alterations amongst patients with metastatic urothelial cancer (mUC) in Ireland. We studied patients who received a targeted therapy following the detection of an oncogenic alteration on NGS and assessed their outcomes.

METHODS

Patients with a diagnosis of mUC between 2017 and 2022 were identified from Urology MDT databases as well as pharmacy databases across three Irish cancer centres. A retrospective review of patient notes including a comprehensive review of histopathology, radiology data, prior therapies and NGS reports was carried out for each patient.

RESULTS

111 patients diagnosed with mUC between 2017 and 2022 were identified for inclusion across three hospital sites. NGS was carried out on the tumour specimens of 66 patients (59%). Thirty-six potentially therapeutically targetable alterations were identified amongst thirty-five patients. The most frequent alterations identified were PIK3CA mutations, FGFR3 mutations or fusions and ERBB2 somatic mutations. Fifteen patients (13.5%) received therapy directed at a genetic alteration. The most common targeted therapy received was erdafitinib (60%) followed by trastuzumab (33%) with one patient receiving alpelisib monotherapy. The median duration of treatment with targeted therapy was 3 months (range 1-34 months). Two patients were observed to have durable responses to erdafitinib approaching 3 years duration.

CONCLUSIONS

This study provides an understanding of the use of NGS and prevalence of genomic alterations in an Irish patient population.

Plasmacytoid urothelial carcinoma of the urinary bladder-A clinicopathological and molecular analysis of 52 cases

Plasmacytoid urothelial carcinoma (UC) is a rare histologic subtype of bladder cancer that is associated with an aggressive clinical behavior. We analyzed the clinicopathologic and molecular features of plasmacytoid UC in 52 patients from a single institute. The patients included 44 men and 8 women, with a mean age of 64 years (range, 41-91 years). All bladder cancers were high-grade UC, and plasmacytoid component accounted for a mean of 47% of bladder tumors (range, 5-100%). Distinct gene mutations were found in most plasmacytoid UCs (n = 49); the most common mutations were TP53 (n = 30), followed by TERT (n = 20), and CDH1 (n = 18). Copy number analysis was performed in 34 patients, and 13 of them showed copy number variations. Expression of HER2 was analyzed in 18 patients by immunohistochemistry, and 3 of them showed HER2 overexpression, which was confirmed by fluorescence in situ hybridization analysis. Thirty-two patients died of disease in a median of 15 months (range, 1-45 months). No individual gene mutations were significantly associated with clinical outcome, but mutations in the mammalian target of rapamycin (mTOR) pathway, including PICK3CA and PIK3R1 mutations, were associated with a significantly shorter survival duration (p < 0.05). Plasmacytoid UC is an aggressive histologic subtype that demonstrates frequent somatic gene mutations and CNVs, which may underlie its oncogenesis and progression. Gene mutations of the mTOR pathway are associated with poor outcome in a subset of patients with plasmacytoid UC.

N-myc downstream-regulated gene 1 can promote vasculogenic mimicry and angiogenesis in urothelial carcinoma

Urothelial carcinoma (UC) of the bladder is a common cause of cancer-related death worldwide. Vasculogenic mimicry (VM) is a process by which the malignant cells can generate vascular-like structures formed of periodic acid-Schiff (PAS) positive/CD31 negative extracellular matrix independent of angiogenesis and thus promotes tumor progression. N-myc downstream-regulated gene 1 (NDRG1) is a protein that can modulate tumor angiogenesis; however, its role in regulating tumor angiogenesis and VM formation has not been previously investigated in UC. This study aims to evaluate the role of intra-tumor microvessel density (MVD) (as a surrogate measure of angiogenesis), VM, and NDRG1 in UC and their correlation with different clinicopathologic features, then assess the correlation between them in UC. Sixty specimens of UC of the bladder were included. PAS-CD31 immunohistochemical double staining method was used to evaluate the intra-tumor MVD and VM. Immunohistochemical expression of NDRG1 was also examined. VM and NDRG1 expression were detected in 41.7% and 83.3% of UC specimens respectively. The mean of intra-tumor MVD, VM area, and NDRG1 was significantly higher in tumors with higher grade, lymphovascular invasion, and higher T stage. NDRG1 expression was positively correlated with MVD and VM. We can suggest that MVD, VM, and NDRG1 may serve as poor prognostic markers for UC. The positive correlation between NDRG1 and both MVD and VM may provide the first evidence that NDRG1 can induce tumor angiogenesis and VM in UC which may offer a novel pathway for further therapeutic strategies.

MRI-Based Machine Learning Radiomics for Preoperative Assessment of Human Epidermal Growth Factor Receptor 2 Status in Urothelial Bladder Carcinoma

BACKGROUND

The human epidermal growth factor receptor 2 (HER2) has recently emerged as hotspot in targeted therapy for urothelial bladder cancer (UBC). The HER2 status is mainly identified by immunohistochemistry (IHC), preoperative and noninvasive methods for determining HER2 status in UBC remain in searching.

PURPOSES

To investigate whether radiomics features extracted from MRI using machine learning algorithms can noninvasively evaluate the HER2 status in UBC.

STUDY TYPE

Retrospective.

POPULATION

One hundred ninety-five patients (age: 68.7 ± 10.5 years) with 14.3% females from January 2019 to May 2023 were divided into training (N = 156) and validation (N = 39) cohorts, and 43 patients (age: 67.1 ± 13.1 years) with 13.9% females from June 2023 to January 2024 constituted the test cohort (N = 43).

FIELD STRENGTH/SEQUENCE

3 T, T2-weighted imaging (turbo spin-echo), diffusion-weighted imaging (breathing-free spin echo).

ASSESSMENT

The HER2 status were assessed by IHC. Radiomics features were extracted from MRI images. Pearson correlation coefficient and the least absolute shrinkage and selection operator (LASSO) were applied for feature selection, and six machine learning models were established with optimal features to identify the HER2 status in UBC.

STATISTICAL TESTS

Mann-Whitney U-test, chi-square test, LASSO algorithm, receiver operating characteristic analysis, and DeLong test.

RESULTS

Three thousand forty-five radiomics features were extracted from each lesion, and 22 features were retained for analysis. The Support Vector Machine model demonstrated the best performance, with an AUC of 0.929 (95% CI: 0.888-0.970) and accuracy of 0.859 in the training cohort, AUC of 0.886 (95% CI: 0.780-0.993) and accuracy of 0.846 in the validation cohort, and AUC of 0.712 (95% CI: 0.535-0.889) and accuracy of 0.744 in the test cohort.

DATA CONCLUSION

MRI-based radiomics features combining machine learning algorithm provide a promising approach to assess HER2 status in UBC noninvasively and preoperatively.

EVIDENCE LEVEL

2 TECHNICAL EFFICACY: Stage 3.

Characterizing the Genomic Landscape of the Micropapillary Subtype of Urothelial Carcinoma of the Bladder Harboring Activating Extracellular Mutations of ERBB2

The micropapillary subtype of urothelial carcinoma (MPUC) of the bladder is a very aggressive histological variant of urothelial bladder cancer (UBC). A high frequency of MPUC contains activating mutations in the extracellular domain (ECD) of ERBB2. We sought to further characterize ERBB2 ECD-mutated MPUC to identify additional genomic alterations that have been associated with tumor progression and therapeutic response. In total, 5,485 cases of archived formalin-fixed, paraffin-embedded UBC underwent comprehensive genomic profiling to identify ERBB2 ECD-mutated MPUC and evaluate the frequencies of genomic co-alterations. We identified 219 cases of UBC with ERBB2 ECD mutations (74% S310F and 26% S310Y), of which 63 (28.8%) were MPUC. Genomic analysis revealed that TERT, TP53, and ARID1A were the most common co-altered genes in ERBB2-mutant MPUC (82.5%, 58.7%, and 39.7%, respectively) and did not differ from ERBB2-mutant non-MPUC (86.5%, 51.9%, and 35.3%). The main differences between ERBB2 ECD-mutated MPUC compared with non-MPUC were KMT2D, RB1, and MTAP alterations. KMT2D and RB1 are tumor-suppressor genes. KMT2D frequency was significantly decreased in ERBB2 ECD-mutated MPUC (6.3%) in contrast to non-MPUC (27.6%; P < .001). RB1 mutations were more frequent in ERBB2 ECD-mutated MPUC (33.3%) than in non-MPUC (17.3%; P = .012). Finally, MTAP loss, an emerging biomarker for new synthetic lethality-based anticancer drugs, was less frequent in ERBB2 ECD-mutated MPUC (11.1%) than in non-MPUC (26.9%; P = .018). Characterizing the genomic landscape of MPUC may not only improve our fundamental knowledge about this aggressive morphological variant of UBC but also has the potential to identify possible prognostic and predictive biomarkers that may drive tumor progression and dictate treatment response to therapeutic approaches.

Emerging strategy for the treatment of urothelial carcinoma: Advances in antibody-drug conjugates combination therapy

Urothelial carcinoma (UC) is a prevalent malignant tumor involving the urinary system. Although there are various treatment modalities, including surgery, chemotherapy, and immune checkpoint inhibitor (ICI) therapy, some patients experience disease recurrence and metastasis with poor prognosis and dismal long-term survival. Antibody-drug conjugates (ADCs), which combine the targeting ability of antibody drugs with the cytotoxicity of chemotherapeutic drugs, have recently emerged as a prominent research focus in the development of individualized precision cancer therapy. Although ADCs have improved the overall response rate in patients with UC, their effectiveness remains limited. Currently, ADC-based combination therapies, particularly ADC combined with ICIs, have demonstrated promising efficacy. This combination approach has advanced the treatment of UC, exhibiting the potential to become the standard first-line therapy for advanced UC in the future. This article reviewed clinical trials involving ADC-based combination therapy for UC and discussed the possible challenges and future perspectives to provide guidance for the clinical treatment of UC.

A systematic review and meta-analysis for human epidermal growth factor receptor 2 on upper tract urothelial carcinoma patients

OBJECTIVE

The expression and significance of human epidermal growth factor receptor 2 (Her2) in upper tract urothelial carcinoma (UTUC) remains controversial. Thus, we aimed to systemically review the Her2 expression in UTUC patients and its relationship with pathological characters and clinical outcomes with meta-analysis.

MATERIALS AND METHODS

A systematically computerized search in PubMed, Scopus, Embase and Cochrane was conducted. From a total of 454 related articles, 35 articles were finally reviewed and 16 papers were chosen for further analysis. Pathological characters included tumor stage, grade, lymph node metastasis (LNM) and lymphovascular invasion (LVI). The clinical outcomes included overall survival (OS), recurrence-free survival (RFS), cancer specific survival (CSS), metastatic-free survival (MFS) and progression-free survival (PFS). RevMan software was used for meta-analyses.

RESULTS

In total 16 studies from 1994 to 2020 were chosen, 14 studies used immunohistochemistry to assess the expression of Her2 and 5 studies used in situ hybridization, with a positive rate of 0 to 74.0% and 7.2 to 18.1%, respectively. Her2-positive was significantly associated with stage (pooled HR 1.86; 95 % CI 1.43-2.42), grade (pooled HR 2.81; 95 % CI 1.01-7.85) and LNM (pooled HR 1.93; 95 % CI 1.18-3.15). However, there was no statistically relationship between Her2-positive with LVI (pooled HR 1.48; 95 % CI 0.64-3.46) and RFS (pooled HR 1.41; 95 % CI 0.98-1.83).

CONCLUSIONS

This review indicated that UTUC patients with Her2-positive tended to develop higher stage and grade tumors and LNM. The Her2 expression in UTUC patients deserves further investigation in the future.

TROP-2, NECTIN-4 and predictive biomarkers in sarcomatoid and rhabdoid bladder urothelial carcinoma

Introduction

The surface protein TROP-2/TACSTD2 and the cell adhesion protein NECTIN-4/NECTIN4 are responsible for the efficacy of anticancer therapies based on antibody-drug conjugates (ADC) targeting intracellular microtubules. In contrast with common histologic subtypes of bladder urothelial carcinoma (BUC), little is known of TROP-2 and NECTIN-4 expression in sarcomatoid and rhabdoid BUC.

Aims

In this study, we aimed to analyze TROP-2 and NECTIN-4 expression and additional predictive biomarkers by immunohistochemistry and fluorescence in situ hybridization (FISH) on 35 undifferentiated BUC (28 sarcomatoid and 7 rhabdoid). Wide genomic investigation was also performed on 411 BUC cases of the PanCancer Atlas, focusing on genes related to the microtubule pathways.

Results

Seven of 35 (20%) undifferentiated BUC showed expression of TROP-2. NECTIN-4 was expressed in 10 cases (29%). Seven cases (20%) co-expressed TROP-2 and NECTIN-4. HER-2 FISH was amplified in 5 cases (14%) while HER-2 immunoexpression was observed in 14 cases (40%). PD-L1 scored positive for combined proportion score (CPS) in 66% of cases and for tumor proportion score (TPS) in 51% of cases. Pan-NTRK1-2/3 was elevated in 9 cases (26%) and FGFR-2/3 was broken in 7 of 35 cases (20%). Of 28 sarcomatoid BUC, 9 (32%) were negative for all (TROP-2, NECTIN-4, PD-L1, HER-2, FGFR and pan-NTRK) biomarkers and 3 (11%) expressed all five biomarkers. Among cases with rhabdoid dedifferentiation, 1 of 7 (14%) showed activation of all biomarkers, whereas 2 of 7 (28%) showed none. The mRNA analysis identified microtubule-related genes and pathways suitable for combined ADC treatments in BUC.

Conclusion

Sarcomatoid and rhabdoid BUC do harbor positive expression of the ADC targets TROP-2 or NECTIN-4 in a relatively modest subset of cases, whereas the majority do not. Different combinations of other positive biomarkers may help the choice of medical therapies. Overall, these findings have important clinical implications for targeted therapy for BUC.

Molecular Targeting of the Human Epidermal Growth Factor Receptor-2 (HER2) Genes across Various Cancers

Human epidermal growth factor receptor 2 (HER2) belongs to the ErbB family, a group of four transmembrane glycoproteins with tyrosine kinase activity, all structurally related to epidermal growth factor receptor (EGFR). These tyrosine kinases are involved in the transmission of cellular signals controlling normal cell growth and differentiation. If this transmission goes awry, it can lead to dysregulated growth of the cell. HER2 specifically can be implicated in the pathogenesis of at least eight malignancies. HER2 positivity quickly became a well-characterized indicator of aggressiveness and poor prognosis, with high rates of disease progression and mortality. After realizing the implication of HER2, it first became investigated as a target for treatment in breast cancer, and later expanded to areas of research in other cancer types. To this day, the most therapeutic advancements of anti-HER2 therapy have been in breast cancer; however, there have been strong advancements made in the incorporation of anti-HER2 therapy in other cancer types as well. This comprehensive review dissects HER2 to its core, incorporating the most up to date information. The topics touched upon are discussed in detail and up to 200 published sources from the most highly recognized journals have been integrated. The importance of knowing about HER2 is exemplified by the groundbreaking advancements that have been made, and the change in treatment plans it has brought to the oncological world in the last twenty years. Since its groundbreaking discovery there have been significant breakthroughs in knowledge regarding the actual receptor, the receptors biology, its mechanism of action, and advancements in tests to detect HER2 and significant strides on how to best incorporate targeted treatment. Due to the success of this field thus far, the review concludes by discussing the future of novel anti-HER2 therapy currently in development that everyone should be aware of.

Systematic review of recent advancements in antibody-drug and bicycle toxin conjugates for the treatment of urothelial cancer

Antibody-drug conjugates and bicycle toxin conjugates represent a tremendous advance in drug delivery technology and have shown great promise in the treatment of urothelial cancer. Previously approved systemic therapies, including chemotherapy and immunotherapy, are often impractical due to comorbidities, and outcomes for patients with advanced disease remain poor, even when receiving systemic therapy. In this setting, antibody-drug and bicycle toxin conjugates have emerged as novel treatments, dramatically altering the therapeutic landscape. These drugs harness unique designs consisting of antibody or bicycle peptide, linker, and cytotoxic payload with more targeted delivery than conventional chemotherapy, thus eliminating malignant cells while reducing systemic toxicities. Potential targets investigated in urothelial cancer include Nectin-4, TROP2, HER2, and EphA2. Initial clinical trials demonstrated efficacy in treatment of refractory advanced urothelial cancer, as well as improvement in quality of life. These initial studies led to FDA approval of two antibody-drug conjugates, enfortumab vedotin and sacituzumab govitecan. Moreover, antibody-drug and bicycle toxin conjugates are being studied in ongoing clinical trials in frontline treatment of advanced disease as well as for localized cancer. These studies highlight the potential for additional future therapies with novel targets, novel antibodies, cytotoxic and immunomodulatory payloads, and unique structural designs enhancing efficacy and safety. There is increasing evidence that combinations with other cancer therapies, especially immunotherapy, improve treatment outcomes. The combination of enfortumab vedotin and pembrolizumab was recently approved for first-line treatment of advanced urothelial carcinoma. Despite the great promise of these novel drugs, robust predictive biomarkers are needed to determine the patients who would maximally benefit. This review surveys the rationale and current state of the evidence for these new drugs and describes future directions actively being explored.

Precision Medicine in Urothelial Carcinoma: Current Markers to Guide Treatment and Promising Future Directions

OPINION STATEMENT

The treatment landscape for urothelial cancer has changed dramatically in the last 10 years, with the approval of several new treatments. At the same time, profiling of individual tumors has become more commonplace with widespread availability of molecular testing and immunohistochemistry. For urothelial cancer, this has led to current guidelines recommending that molecular testing be obtained in the metastatic setting, and that it be considered in the setting of locally advanced disease. Between molecular testing and immunohistochemistry testing of tumors, the only current guideline-directed application of these tests is in the identification of FGFR3 or FGFR2 alterations for use of FGFR inhibitors. While additional recurrent molecular alterations linked to the pathogenesis of urothelial cancer have been identified, the ability to successfully "drug" the pathways association with such alterations remains limited. There has been extensive research into whether expression of particular proteins might inform specific treatment approaches such as the use of PD-L1 testing to guide immune checkpoint blockade. With the integration of antibody-drug conjugates into the treatment armamentarium for urothelial cancer, ongoing research is seeking to determine whether expression of the targets of these therapies, such as Nectin 4, Trop-2, or HER2, could help to guide treatment.

Homologous recombination mRNAs (RAD21, RAD50 and BARD1) have a potentially poor prognostic role in ERBB2-low bladder cancer patients

Human epidermal growth factor receptor 2 (HER2/ERBB2) factor is known to be implicated in many malignancies and the potential of it as a prognostic biomarker was reported years ago. Molecular subtypes of HER2/ERBB2 negative and positive with distinct clinical outcomes have been identified in recent years; however, it is still under investigation for bladder cancer. This study evaluates the biological and prognostic significance of RAD21, RAD50 and BARD1 (homologous recombination biomarkers) mRNA levels with ERBB2 low and high expression to explore their impact on bladder cancer patient survival and cancer aggressiveness. The expression of ERBB2, RAD21, RAD50 and BARD1 mRNA levels was assessed in The Cancer Genome Atlas (TCGA) bladder cancer dataset along with four validation cohorts. Outcome analysis was evaluated using disease-free survival (DFS) and overall survival (OS). Univariate and multivariate analysis were used to evaluate the relationship between RAD21, RAD50, BARD1 and ERBB2 expression and clinicopathological variables. A significant increase in mRNA expression levels of RAD21, RAD50 and BARD1 was noticed in ERBB2-low patients compared to ERBB2-high patients. This overexpression of the homologous recombination repair transcripts was associated with poor outcome in ERBB2-low tumors, not in ERBB2-high tumors. Furthermore, the combined expression of high RAD21/RAD50, high RAD21/BARD1 or high RAD50/BARD1 were significantly associated with worse DFS and a better outcome for those with low co-expression in the ERBB2-low cohort. High expression of either RAD21/RAD50 or RAD21/BARD1 in ERBB2-low cohort associated with higher chance of metastasis. In addition, gene expression of BARD1 alone or in combination with RAD50 acted as an independent prognostic factor for worst survival. The data presented in this study reveal a connection between RAD21, RAD50, BARD1 and ERBB2 and patient survival. Importantly, it provided novel findings and potential prognostic markers, particularly in ERBB2-low bladder cancer.

Immunotherapy in urothelial cancer: current status and future directions

INTRODUCTION

Since 2016, the progressive use of immune checkpoint inhibitors (ICIs) starting from second-line treatment has led to an improvement in overall survival in locally advanced and metastatic urothelial cancer (UC). Clinical trials are underway testing the role of ICIs since the first stages of the disease, alone or in combination with standard therapies.

AREAS COVERED

This review summarizes the current updated evidence regarding the role of ICIs in the different stages of UC, the ongoing clinical trials exploring the potential benefit of immunotherapy alone or in combination with standard-of-care therapies, as well as the promising association of ICIs with antibody-drug conjugates (ADCs).

EXPERT OPINION

In the first-line setting, ICIs alone in platinum-unfit patients have shown unconvincing results; the ongoing EV-302 trial will probably suggest enfortumab vedotin plus pembrolizumab as a new effective option. The optimal duration of maintenance immunotherapy is still to be determined, finding a balance with the risk-benefit profile. The clinical benefit of ICIs as second-line treatment is limited to a subset of patients that cannot be definitively established yet. In the next 5 years, a lot of new ADCs will likely emerge for the treatment of UC.

[Assessment of HER2 status of carcinomas of various localizations]

A detailed description of the methodological aspects of the evaluation of HER2-status in carcinomas of such localizations as the mammary gland, pancreas, salivary glands, stomach, colon, endometrium, bladder, lungs is presented. Approaches and criteria for assessing HER2 status from methodological and clinical points of view are analyzed. The data are systematized in tables for use in practical diagnostic work.