Assessing HER2 gene amplification as a potential target for therapy in invasive urothelial bladder cancer with a standardized methodology: results in 1005 patients

Effects of trastuzumab emtansine on canine urothelial carcinoma cells in vitro and in vivo

Urothelial carcinoma (UC) is the most common malignancy of the urinary tract in dogs and has aggressive behaviour. Although human epidermal growth factor receptor 2 (HER2) is a known therapeutic target with evidence in canine UC, the efficacy of anti-HER2 antibody drugs remains unknown. This study aimed to investigate the effects of anti-HER2 antibody drugs including trastuzumab and trastuzumab emtansine (T-DM1) on canine UC cell lines in vitro and in vivo. Four canine UC cell lines (Nene, TCCUB, Love, and Sora) were used. In western blotting, HER2 protein expression was observed in all the cell lines. Although both trastuzumab and T-DM1 showed dose-dependent growth inhibitory activity in the cell lines, T-DM1 showed much stronger activity than that of trastuzumab. In flow cytometry analyses with the canine UC cell line (Sora), T-DM1 but not trastuzumab significantly increased the percentages of early and late apoptotic cells in annexin V apoptotic assays and the sub-G1 phase fraction in cell cycle analyses. For the in vivo experiment, the canine UC cells (Sora) were subcutaneously injected into nude mice. Four days after inoculation, trastuzumab, T-DM1, or vehicle was administered intraperitoneally once a week for three times. Tumour volumes were significantly smaller in the T-DM1 group compared to the trastuzumab and vehicle control groups. These findings indicate that T-DM1 exerts a stronger antitumour effect than that of trastuzumab on canine UC cells in vitro and in vivo, possibly by inducing apoptosis due to DM1.

Frequency and Nature of Genomic Alterations in ERBB2-Altered Urothelial Bladder Cancer

BACKGROUND

Human epidermal growth factor-2 (HER2) overexpression is an oncogenic driver in many solid tumors, including urothelial bladder cancer (UBC). In addition, activating mutations in the ERBB2 gene have been shown to play an oncogenic role similar to ERBB2 amplification.

OBJECTIVE

To describe and compare the frequency and nature of genomic alterations (GA) of ERBB2-altered (mutations, amplification) and ERBB2 wild-type UBC.

PATIENTS AND METHODS

Using a hybrid capture-based comprehensive profiling assay, 9518 UBC cases were grouped by ERBB2 alteration and evaluated for all classes of genomic alterations (GA), tumor mutational burden (TMB), microsatellite instability (MSI), genome-wide loss of heterozygosity (gLOH), and genomic mutational signature. PD-L1 expression was measured by immunohistochemistry (Dako 22C3). Categorical statistical comparisons were performed using Fisher's exact tests.

RESULTS

A total of 602 (6.3%) UBC cases featured ERBB2 extracellular domain short variant (SV) GA (ECDmut+), 253 (2.7%) cases featured ERBB2 kinase domain SV GA (KDmut+), 866 (9.1%) cases had ERBB2 amplification (amp+), and 7797 (81.9%) cases were ERBB2 wild-type (wt). European genetic ancestry of ECDmut+ was higher than ERBB2wt. Numerous significant associations were observed when comparing GA by group. Notably among these, CDKN2A/MTAP loss were more frequent in ERBB2wt versus ECDmut+ and amp+. ERBB3 GA were more frequent in ECDmut+ and KDmut+ than ERBB2wt. TERT GA were more frequent in ECDmut+, KDmut+, and amp+ versus ERBB2wt. TOP2A amplification was significantly more common in ECDmut+ and amp+ versus ERBB2wt, and TP53 SV GA were significantly higher in ERBB2 amp+ versus ERBB2wt. Mean TMB levels were significantly higher in ECDmut+, KDmut+, and amp+ than in ERBB2wt. Apolipoprotein B mRNA-editing enzyme, catalytic polypeptides (APOBEC) signature was more frequent in ECDmut+, KDmut+, and amp+ versus ERBB2wt. No significant differences were observed in PD-L1 status between groups, while gLOH-high status was more common in amp+ versus ERBB2wt. MSI-high status was more frequent in KDmut+ versus ERBB2wt, and in ERBB2wt than in amp+.

CONCLUSIONS

We noted important differences in co-occurring GA in ERBB2-altered (ECDmut+, KDmut+, amp+) versus ERBB2wt UBC, as well as higher mean TMB and higher APOBEC mutational signature in the ERBB2-altered groups. Our results can help refine future clinical trial designs and elucidate possible response and resistance mechanisms for ERBB2-altered UBC.

Antibody-drug conjugates targeting HER2 for the treatment of urothelial carcinoma: potential therapies for HER2-positive urothelial carcinoma

Urothelial carcinoma (UC) is a common cancer characterized by high morbidity and mortality rates. Despite advancements in treatment, challenges such as recurrence and low response rates persist. Antibody-drug conjugates (ADCs) have emerged as a promising therapeutic approach for various cancers, although their application in UC is currently limited. This review focuses on recent research regarding ADCs designed to treat UC by targeting human epidermal growth factor receptor 2 (HER2), a surface antigen expressed on tumor cells. ADCs comprise three main components: an antibody, a linker, and a cytotoxic payload. The antibody selectively binds to tumor cell surface antigens, facilitating targeted delivery of the cytotoxic drug, while linkers play a crucial role in ensuring stability and controlled release of the payload. Cleavable linkers release the drug within tumor cells, while non-cleavable linkers ensure stability during circulation. The cytotoxic payload exerts its antitumor effect by disrupting cellular pathways. HER2 is commonly overexpressed in UCs, making it a potential therapeutic target. Several ADCs targeting HER2 have been approved for cancer treatment, but their use in UC is still being tested. Numerous HER2 ADCs have demonstrated significant growth inhibition and induction of apoptosis in translational models of HER2-overexpressing bladder cancer. Ongoing clinical trials are assessing the efficacy and safety of ADCs targeting HER2 in UC, with the aim of determining tumor response and the potential of ADCs as a treatment option for UC patients. The development of effective therapies with improved response rates and long-term effectiveness is crucial for advanced and metastatic UC. ADCs targeting HER2 show promise in this regard and merit further investigation for UC treatment.

Predictive and prognostic biomarkers in urological tumours

Advancements in cutting-edge molecular profiling techniques, such as next-generation sequencing and bioinformatic analytic tools, have allowed researchers to examine tumour biology in detail and stratify patients based on factors linked with clinical outcome and response to therapy. This manuscript highlights the most relevant prognostic and predictive biomarkers in kidney, bladder, prostate and testicular cancers with recognised impact in clinical practice. In bladder and prostate cancer, new genetic acquisitions concerning the biology of tumours have modified the therapeutic scenario and led to the approval of target directed therapies, increasing the quality of patient care. Thus, it has become of paramount importance to choose adequate molecular tests, i.e., FGFR screening for urothelial cancer and BRCA1-2 alterations for prostate cancer, to guide the treatment plan for patients. While no tissue or blood-based biomarkers are currently used in routine clinical practice for renal cell carcinoma and testicular cancers, the field is quickly expanding. In kidney tumours, gene expression signatures might be the key to identify patients who will respond better to immunotherapy or anti-angiogenic drugs. In testicular germ cell tumours, the use of microRNA has outperformed conventional serum biomarkers in the diagnosis of primary tumours, prediction of chemoresistance, follow-up monitoring, and relapse prediction.

HER2-targeted therapies in cancer: a systematic review

Abnormal alterations in human epidermal growth factor receptor 2 (HER2, neu, and erbB2) are associated with the development of many tumors. It is currently a crucial treatment for multiple cancers. Advanced in molecular biology and further exploration of the HER2-mediated pathway have promoted the development of medicine design and combination drug regimens. An increasing number of HER2-targeted drugs including specific monoclonal antibodies, tyrosine kinase inhibitors (TKIs), and antibody-drug conjugates (ADCs) have been approved by the U.S. Food and Drug Administration. The emergence of ADCs, has significantly transformed the treatment landscape for various tumors, such as breast, gastric, and bladder cancer. Classic monoclonal antibodies and novel TKIs have not only demonstrated remarkable efficacy, but also expanded their indications, with ADCs in particular exhibiting profound clinical applications. Moreover the concept of low HER2 expression signifies a breakthrough in HER2-targeted therapy, indicating that an increasing number of tumors and patients will benefit from this approach. This article, provides a comprehensive review of the underlying mechanism of action, representative drugs, corresponding clinical trials, recent advancements, and future research directions pertaining to HER2-targeted therapy.

Advances in HER2-Targeted Treatment for Advanced/Metastatic Urothelial Carcinoma

Urothelial carcinoma (UC) represents a common malignancy of the urinary system that can involve the kidneys, ureter, bladder, and urethra. Advanced/metastatic UC (mUC) tends to have a poor prognosis. UC ranks third in terms of human epidermal growth factor receptor 2 (HER2) overexpression among all tumors. However, multiple studies found that, unlike breast cancer, variable degrees of HER2 positivity and poor consistency between HER2 protein overexpression and gene amplification have been found. Trials involving trastuzumab, pertuzumab, lapatinib, afatinib, and neratinib have failed to prove their beneficial effect in patients with HER2-positive mUC, and a clinical trial on T-DM1 (trastuzumab emtansine) was terminated prematurely because of the adverse reactions. However, a phase II trial showed that RC48-ADC was effective. In this review, we provided an in-depth overview of the advances in the research regarding HER2-targeted therapy and the role of HER2 in mUC. Furthermore, we also discussed the prospects of potential strategies aimed at overcoming anti-HER2 resistance, and summarize the novel anti-HER2 approaches for the management of mUC used in recent clinical trials.

A HER2-targeted Antibody-Drug Conjugate, RC48-ADC, Exerted Promising Antitumor Efficacy and Safety with Intravesical Instillation in Preclinical Models of Bladder Cancer

More than half of non-muscle-invasive bladder cancer (NMIBC) patients eventually relapse even if treated with surgery and BCG without optional bladder-preserving therapy. This study aims to investigate the antitumor activity and safety of a HER2-targeted antibody-drug conjugate, RC48-ADC, intravesical instillation for NMIBC treatment. In this preclinical study, it is revealed that human epidermal growth factor receptor 2 (HER2) expression scores of 1+, 2+, and 3+ are recorded for 16.7%, 56.2%, and 14.6% of NMIBC cases. The antitumor effect of RC48-ADC is positively correlated with HER2 expression in bladder cancer (BCa) cell lines and organoid models. Furthermore, RC48-ADC is revealed to exert its antitumor effect by inducing G2/M arrest and caspase-dependent apoptosis. In an orthotopic BCa model, tumor growth is significantly inhibited by intravesical instillation of RC48-ADC versus disitamab, monomethyl auristatin E, epirubicin, or phosphate-buffered saline control. The potential toxicity of intravesical RC48-ADC is also assessed by dose escalation in normal nude mice and revealed that administration of RC48-ADC by intravesical instillation is safe within the range of effective therapeutic doses. Taken together, RC48-ADC demonstrates promising antitumor effects and safety with intravesical administration in multiple preclinical models. These findings provide a rational for clinical trials of intravesical RC48-ADC in NMIBC patients.

Immunohistochemical expression of CD117/KIT, HER2, and Erβ in schistosomal and non-schistosomal urothelial carcinoma of Egyptian patients

Bladder carcinoma is an endemic problem in Egypt with schistosomiasis being an additional risk factor. Due to gender disparities, Erβ investigation and its role in modulating chemosensitivity are studied. CD117/KIT expression is also considered since the emergence of the targets of the tyrosine kinase inhibitor imatinib mesylate (Gleevec). HER2 is one of the established therapeutic targets in many cancers. We aimed to investigate CD117/KIT immunoexpression in schistosomal and non-schistosomal urothelial carcinoma of Egyptian patients and its relationship with HER2 and Erβ expressions, correlating it with pertinent variables that will help to provide better treatment options of possible combined targeted and hormonal therapy that might be effective against this aggressive malignancy. Sixty cases of bladder carcinoma were tested. Depending on the schistosomiasis association status of each case, two groups have been established with 30 cases each. CD117/KIT, HER2, and ERβ immunostaining were done and correlated with clinico- immuno-pathological parameters. CD117/KIT expression was seen in 71.7% of cases that correlated significantly with schistosomiasis (P = 0.01). In addition, a positive correlation was detected between schistosomiasis association and the percentage of immunostained cells and intensity score of CD117/KIT with P = 0.027, 0.01, respectively. 30% and 61.7% of cases were positively stained with HER2 and Erβ, respectively, with no significant relation with schistosomiasis. Due to the high expression, we found further clinical trials are needed to offer individualized targeted therapeutic options in urothelial tumors using anti-CD117/KIT, HER2, and ERβ other than limited traditional chemo- and nontargeted therapies.

Wnt/β-catenin pathway is a key signaling pathway to trastuzumab resistance in gastric cancer cells

BACKGROUND

Trastuzumab is the only approved target agent for the first-line treatment of human epidermal growth factor receptor-2 (HER-2) positive gastric cancer; however, trastuzumab resistance is a major problem in clinical practice. To comprehend the mechanism of trastuzumab resistance, we focused on the Wnt/β-catenin signaling pathway and its influence on the phenotypes and behavior of trastuzumab-resistant gastric cancer cells.

METHODS

Trastuzumab-resistant NCI-N87R cells were established in vitro from the human gastric cancer cell line NCI-N87 by dose-escalating repeated trastuzumab treatment. We investigated the phenotypes of NCI-N87R cells, including Wnt signaling pathway activity. Gastric cancer organoid cells were incubated with complete medium and Wnt3a-depletion medium, and their resistance to trastuzumab was compared.

RESULTS

NCI-N87R exhibited stemness and epithelial-mesenchymal transition (EMT)-like phenotypes, along with decreased levels of the epithelial marker E-cadherin and increased levels of the mesenchymal markers Vimentin and Snail along with an increased Wnt signaling pathway activity. When gastric cancer cells were incubated in Wnt3a-conditioned medium. Wnt signaling pathway activity and resistance to trastuzumab increased. Gastric cancer patient-derived organoids incubated in Wnt3a-depletion medium were more susceptible to dose-dependent inhibition of cell viability by trastuzumab than those incubated in complete medium.

CONCLUSIONS

Trastuzumab-resistant gastric cancer cells exhibited EMT-like phenotype, and trastuzumab resistance was promoted by the Wnt/β-catenin signaling pathway. The Wnt/β-catenin pathway is a key signaling pathway for trastuzumab resistance in gastric cancer cells.

HER2 Expression Associated with Clinical Characteristics and Prognosis of Urothelial Carcinoma in a Chinese Population

BACKGROUND

The frequency of HER2 overexpression in bladder cancer is reported as 9%-61%. HER2 alteration correlates with aggressive disease in bladder cancer. Traditional anti-HER2 targeted therapy has failed to show clinical benefits in patients with advanced urothelial carcinoma .

METHODS

The information on pathologically proven patients with urothelial carcinoma with detected HER2 status was collected from the database of Peking University Cancer Hospital. The HER2 expression, as well as its association with clinical characteristics and prognosis, was analyzed.

RESULTS

A total of 284 consecutive patients with urothelial carcinoma were enrolled. HER2 was positive (IHC 2+/3+) in 44% of urothelial carcinoma. HER2 positivity was found more frequent in UCB than in UTUC (51% vs. 38%). Stage, radical surgery, and histological variant were associated with survival (P < .05). For metastatic patients, multivariate analysis shows that 3 indicators, including liver metastasis, the number of involved organs, and anemia, are independent risk factors of prognosis. Receiving immunotherapy or disitamab vedotin (DV) treatment is an independent protecting factor. The survival of patients with low HER2 expression was also significantly improved by the treatment of DV (P < .001). HER2 expression (IHC 1+, 2+, 3+) was associated with a better prognosis in this population.

CONCLUSION

DV has improved the survival of patients with urothelial carcinoma in the real world. With the new-generation anti-HER2 ADC treatment, HER2 expression is no longer a poor prognostic factor.

Phase II study of a trastuzumab biosimilar in combination with paclitaxel for HER2-positive recurrent or metastatic urothelial carcinoma: KCSG GU18-18

BACKGROUND

Human epidermal growth factor receptor 2 (HER2) is a widely explored therapeutic target in solid tumors. We evaluated the efficacy and safety of trastuzumab-pkrb, a biosimilar of trastuzumab, in combination with paclitaxel, in HER2-positive recurrent or metastatic urothelial carcinoma (UC).

PATIENTS AND METHODS

We enrolled 27 patients; they were administered a loading dose of 8 mg/kg trastuzumab-pkrb on day 1, followed by 6 mg/kg and 175 mg/m2 paclitaxel on day 1 every 3 weeks, intravenously. All patients received six cycles of the combination treatment and continued to receive trastuzumab-pkrb maintenance until disease progression, unacceptable toxicity, or for up to 2 years. HER2 positivity (based on immunohistochemistry analysis) was determined according to the 2013 American Society of Clinical Oncology /College of American Pathologists HER2 testing guidelines. The primary endpoint was objective response rate (ORR); the secondary endpoints were overall survival (OS), progression-free survival (PFS), and safety.

RESULTS

Twenty-six patients were evaluated via primary endpoint analysis. The ORR was 48.1% (1 complete and 12 partial responses) and the duration of response was 6.9 months [95% confidence interval (CI) 4.4-9.3 months]. With a median follow-up of 10.5 months, the median PFS and OS were 8.4 months (95% CI 6.2-8.8 months) and 13.5 months (95% CI 9.8 months-not reached), respectively. The most common treatment-related adverse event (TRAE) of any grade was peripheral neuropathy (88.9%). The most common grade 3/4 TRAEs were neutropenia (25.9%), thrombocytopenia (7.4%), and anemia (7.4%).

CONCLUSIONS

Trastuzumab-pkrb plus paclitaxel demonstrates promising efficacy with manageable toxicity profiles in patients with HER2-positive recurrent or metastatic UC.

Ado-tratuzumab emtansine beyond breast cancer: therapeutic role of targeting other HER2-positive cancers

Ado-trastuzumab emtansine (T-DM1) is an antibody-drug conjugate approved by the FDA in 2013 for advanced HER2-positive breast cancer treatment exhibiting promising clinical benefits. However, HER2 overexpression and gene amplification have also been reported in other cancers like gastric cancer, non-small cell lung cancer (NSCLC), and colorectal cancer. Numerous preclinical studies have also revealed the significant antitumor effect of T-DM1 on HER2-positive tumors. With the advancement in research, several clinical trials have been conducted to investigate the antitumor effect of T-DM1. In this review, we briefly introduced the pharmacological effects of T-DM1. We reviewed its preclinical and clinical studies, especially on other HER2-positive cancers, establishing what has been encountered between its preclinical and clinical studies. In clinical studies, we found that T-DM1 has a therapeutic value on other cancers. An insignificant effect was observed on gastric cancer and NSCLC, inconsistent with the preclinical studies.

Phase II study (KAMELEON) of single-agent T-DM1 in patients with HER2-positive advanced urothelial bladder cancer or pancreatic cancer/cholangiocarcinoma

The antibody-drug conjugate trastuzumab emtansine (T-DM1) is approved for human epidermal growth factor receptor 2 (HER2/ERBB2)-positive breast cancer. We aimed to study tumor HER2 expression and its effects on T-DM1 responses in patients with HER2-positive urothelial bladder cancer (UBC) or pancreatic cancer (PC)/cholangiocarcinoma (CC). In the phase II KAMELEON study (NCT02999672), HER2 status was centrally assessed by immunohistochemistry, with positivity defined as non-focal homogeneous or heterogeneous overexpression of HER2 in ≥30% of stained cells. We also performed exploratory biomarker analyses (e.g., gene-protein assay) on tissue samples collected from study participants and consenting patients who failed screening. Of the 284 patients successfully screened for HER2 status (UBC, n = 69; PC/CC, n = 215), 13 with UBC, four with PC, and three with CC fulfilled eligibility criteria. Due to recruitment difficulty, the sponsor terminated KAMELEON prematurely. Of the five responders in the UBC cohort (overall response rate, 38.5%), HER2 expression was heterogeneous in two and homogeneous in three. The one responder in the PC/CC cohort had PC, and the tumor displayed homogeneous expression. In the biomarker-evaluable population, composed of screen-failed and enrolled patients, 24.3% (9/37), 1.5% (1/66), and 8.2% (4/49) of those with UBC, PC, or CC, respectively, had HER2-positive tumors. In a gene-protein assay combining in situ hybridization with immunohistochemistry, greater HER2 homogeneity was associated with increased ERBB2 amplification ratio. In conclusion, KAMELEON showed that some patients with HER2-positive UBC or PC can respond to T-DM1 and provided insight into the prevalence of HER2 positivity and expression patterns in three non-breast tumor types.

"A Review of HER2 overexpression and somatic mutations in cancers"

The Human Epidermal Growth Factor Receptor (HER) proteins family, which includes HER2, are membrane-bound receptors that activate many intracellular pathways associated with growth and development. When there are mutations in HER2, or when it becomes overexpressed, it can cause oncogenesis and offer differential prognosis and treatment across almost all cancer types. Both mutations in HER2 and its overexpression have distinct mechanisms by which they can cause these effects in cancers. This review outlines how HER2's normal pathway is altered in both overexpression and mutation and compiles all the well-known mechanisms by which HER2 can cause oncogenesis. Finally, this review briefly outlines how HER2 mutants and HER2 overexpression is detected, and how their detection can lead to different prognosis and treatment in cancers.

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.

Expression of epidermal growth factor receptor and human epidermal growth factor receptor 2 in urothelial bladder carcinoma in an Egyptian cohort: Clinical implication and prognostic significance

BACKGROUND

Bladder cancer (BC) has a particular importance in Egyptian patients due to aggressive behavior and absence of prognostic markers.

OBJECTIVE

To evaluate the expression of gene and protein expression of HER2 and epidermal growth factor (EGFR) in Egyptian patients with BC and ultimately to investigate their clinical implication and prognostic significance.

MATERIAL AND METHODS

The study was carried out on 46 patients with urothelial bladder BC. Tissue were obtained from transurethral resection (N = 22) and radical cystectomy (N = 24) specimens. The original hematoxylin and eosin slides were re-evaluated and the formalin fixed, paraffin-embedded (FFPE) tissues which had sufficient tumor tissue (>75%) and minimal or absent tumor necrosis were selected for immunohistochemistry (IHC) and RNA extraction. Furthermore, five control biopsies were obtained from patients with cystitis. Follow-up data were retrieved from the medical records which included the treatment regimen, disease recurrence and/or progression, and survival.

RESULTS

EGFR and HER2 protein were overexpressed in 35% and 46% of patients respectively. EGFR was correlated with the tumor size, grade and pathological stage, with a similar trend for HER2. The recurrence rate was higher in patients with expression of any of the markers. Gene expression was significantly higher (10.6-folds) for EGFR and (21-folds) for HER2 in patients with BC in comparison to control patients. Survival analysis showed lower median disease-free survival in association with HER2 protein overexpression.

CONCLUSIONS

Our data highlighted the prognostic significance of EGFR and HER in BC and proposed their possible use as predictive markers and potential therapeutic targets.

HER2 expression in urothelial carcinoma, a systematic literature review

Background

Urothelial carcinoma (UC) is a common malignancy with significant associated mortality. Recent clinical trials suggest an emerging role for HER2-targeted therapy. Testing for HER2 expression in UC is not part of current routine clinical practice. In consequence, the prevalence of HER2 expression in UC is not well defined.

Methods

A systematic literature review (SLR) was conducted to characterize HER2 expression in both locally advanced unresectable or metastatic (LA/mUC) and earlier stage UC, classified as HER2+, HER2-low, HER2-. HER2+ was defined as an immunohistochemistry (IHC) score of 3+ or IHC 2+ and ISH/FISH+. HER2-low was defined as an IHC score of 2+ and ISH/FISH- or IHC 1+. HER2- was defined as an IHC score of 0. Weighted averages were calculated to generate an estimate of the population prevalence.

Results

A total of 88 studies were identified, with 45, 30, and 13 studies investigating LA/mUC, earlier stage UC, and mixed stage/unspecified, respectively. The most common assays used were Dako HercepTest and Ventana Pathway anti-HER2/neu (4B5) for IHC to assess HER2 protein expression; Abbott PathVysion HER-2 DNA Probe Kit, FoundationOne CDx, and Guardant360 CDx for assessing HER2 gene amplification. The most frequently cited scoring guidelines were ASCO/CAP guidelines for breast cancer and gastric cancer, though most studies defined their own criteria for HER2 expression. Using the pre-specified definition, HER2+ prevalence ranged from 6.7% to 37.5% with a weighted average of 13.0% in LA/mUC. Only 1 study presented data that could be classified as HER2+ based on pre-specified criteria in earlier stage UC patients, and this study represented a likely outlier, at 76.0%.

Conclusion

The results from this SLR help to shed light on HER2 expression in UC, a potentially clinically relevant biomarker-driven subpopulation for emerging HER2-directed regimens. Results of this SLR illuminate the variability in how HER2+ status expression levels are being assessed and how HER2+ is defined. Consensus on standardized HER2 testing and scoring criteria is paramount to better understand the clinical relevance in patients with UC.

Molecular and clinicopathological characteristics of ERBB2 gene fusions in 32,131 Chinese patients with solid tumors

ERBB2 amplification is one of the most important and mature targets for HER2-targeted drug therapy. Somatic mutations of ERBB2 in the tyrosine kinase domain have been studied extensively, and play a role in response to anti-HER2 therapy among different cancer types. However, ERBB2 fusion has not been got attention and its relevance to HER2-targeted therapy is unclear. We comprehensively characterized ERBB2 fusions from next-generation sequencing (NGS) data between May 2018 and October 2021 in 32,131 various solid tumors. Among the tumors, 0.28% harbored ERBB2 fusions, which occurred more commonly in gastroesophageal junction cancer (3.12%; 3/96), breast cancer (1.89%; 8/422), urothelial carcinoma (1.72%; 1/58), and gastric cancer (1.60%; 23/1,437). Our population presented with a median age of 65 years (range 28 to 88 years), a high proportion of men (55 men vs 34 women; 61.80%). Among the patients with ERBB2 fusions, TP53 (82%), APC (18%), and CDK4 (15%) were the top3 co-mutant genes. What’s more, most patients with ERBB2 fusion also had ERBB2 amplification (75.28%; 67/89), which was similar to the data in the TCGA database (88.00%; 44/50). Furthermore, TCGA database shows that patients with ERBB2 fusions in pan-cancer had a worse prognosis than those without ERBB2 fusions, as well as in breast cancer. Besides, ERBB2 amplification combined with ERBB2 fusion had worse prognosis than those with only ERBB2 amplification. ERBB2 fusion may interfere the effect of anti-HER2-targeted antibody drugs and influence the prognosis of patients with ERBB2 amplification. Prospective clinical trials are warranted to confirm the results in the future.

A synthetic lethal strategy using PARP and ATM inhibition for overcoming trastuzumab resistance in HER2-positive cancers

Despite its clinical efficacy in HER2-positive cancers, resistance to trastuzumab inevitably occurs. The DNA damage response (DDR) pathway is essential for maintaining genomic stability and cell survival. However, the role of the DDR pathway in HER2-positive tumors and trastuzumab resistance remains elusive. In this study, we verified that increased PARP1 expression in trastuzumab-resistant (TR) cells, owing to its augmented stability by escape from proteasomal degradation, confers tolerability to trastuzumab-induced DNA damage. Interruption of PARP1 in TR cells restrains its cellular growth, while simultaneously activating ATM to retain its genome stability. Dual inhibition of PARP and ATM induces synthetic lethality in TR cells by favoring the toxic NHEJ pathway instead of the HRR pathway. Our results highlight the potential of clinical development of DDR-targeting strategies for trastuzumab-resistant HER2-positive cancer patients.

Clinically undetected plasmacytoid urothelial carcinoma of the urinary bladder with non-mass-forming metastases in multiple organs: an autopsy case

This case report outlines a clinically undetected urinary bladder plasmacytoid urothelial carcinoma (PUC) with multiple metastases detected at autopsy. An 89-year-old man presented with edema in the lower limbs. Pleural fluid cytology revealed discohesive carcinomatous cells, although imaging studies failed to identify the primary site of tumor. The patient died of respiratory failure. Autopsy disclosed a prostate tumor and diffusely thickened urinary bladder and rectum without distinct tumorous lesions. Histologically, the tumor consisted of acinar-type prostate adenocarcinoma with no signs of metastasis. Additionally, small, plasmacytoid tumor cells were observed in the urinary bladder/rectum as isolated or small clustering fashions. These metastasized to the lungs, intestine, generalized lymph nodes in a non-mass-forming manner. Combined with immunohistochemical studies, these tumor cells were diagnosed PUC derived from the urinary bladder. Both clinicians and pathologists should recognize PUC as an aggressive histological variant, which can represent a rapid systemic progression without mass-forming lesions.

Progress in the Research and Targeted Therapy of ErbB/HER Receptors in Urothelial Bladder Cancer

Bladder cancer is a lethal malignancy and a majority of bladder cancer arise from urothelial cells. Infiltration and metastasis are barriers for the radical cystectomy to achieve favored outcome and are the main cause of death. Systemic therapy, including chemotherapy, targeted therapy, and immunotherapy, is fundamental for these patients. erbB/HER receptors are found to be overexpressed in a subgroup of urothelial carcinoma, targeting erbB/HER receptors in these patients was found to be an efficient way in the era of genetic testing. To evaluate the role of erbB/HER receptors in bladder cancer, we reviewed the literature and ongoing clinical trials as regards to this topic to unveil the context of erbB/HER receptors in bladder cancer, which probably help to solidate the theoretical basis and might instruct further research.

Reappraisal of HER2 Amplification in High-Grade Urothelial Carcinoma Based on 2018 ASCO/CAP Clinical Practice Guidelines

OBJECTIVES

To examine and compare human epidermal growth factor receptor 2 (HER2) amplification status in high-grade urothelial carcinoma (HGUCa), using both 2013 and 2018 HER2 reporting guidelines for breast carcinoma from the American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAP).

METHODS

HER2 status by fluorescence in situ hybridization (FISH) assay in 78 cases of HGUCa was compared using 2013 and 2018 HER2 reporting guidelines.

RESULTS

HER2 amplification was observed in 22 (28.2%) of 78 tumors, of which 17 were in group 1, 1 in group 2, and 2 each in groups 3 and 4 (FISH assay, 2018). The remaining 14 HER2-amplified tumors (FISH assay, 2013) became negative, falling into group 2 (FISH assay, 2018) and were either negative or equivocal on immunohistochemistry (IHC, 2018). All FISH-negative tumors (n = 37) using 2013 criteria remained negative (group 5, 2018). FISH-equivocal tumors (2013) were further categorized into HER2 amplified (n = 1) and HER2 negative (n = 4) (2018). Overall, 20 (25.6%) tumors had discordant HER2 FISH results (2018 vs 2013).

CONCLUSIONS

Implementing 2018 guidelines, HER2 amplification decreased from 36 to 22 cases. The group with a HER2/CEP17 ratio of 2 or more and average HER2 copy number less than 4 (group 2) were predominantly negative by IHC, suggesting a biologically distinct group of HGUCa that is different from HER2-amplified tumors, which may not respond to HER2-targeted therapy.

Recombinant immunotoxins development for HER2-based targeted cancer therapies

Understanding the molecular mechanisms of cancer biology introduces targeted therapy as a complementary method along with other conventional therapies. Recombinant immunotoxins are tumor specific antibodies that their recognizing fragment is utilized for delivering modified toxins into tumor cells. These molecules have been considered as a targeted strategy in the treatment of human cancers. HER2 tumor biomarker is a transmembrane tyrosine kinase receptor that can be used for targeted therapies in the forms of anti-HER2 monoclonal antibodies, antibody-drug conjugates and immunotoxins. There have been many studies on HER2-based immunotoxins in recent years, however, little progress has been made in the clinical field which demanded more improvements. Here, we summarized the HER2 signaling and it's targeting using immunotherapeutic agents in human cancers. Then, we specifically reviewed anti-HER2 immunotoxins, and their strengths and drawbacks to highlight their promising clinical impact.

Distinctive morphological and molecular features of urothelial carcinoma with an inverted growth pattern

Urothelial carcinoma with an inverted growth pattern (UC-IGP) is a peculiar entity within the spectrum of urothelial lesions. While efforts have been made over the last few decades to unravel its carcinogenesis and relationship with conventional urothelial carcinoma, the exact classification of inverted urothelial lesions is a matter of debate. The morphological features of UC-IGP pose several issues in differential diagnosis with other mostly benign lesions. Various techniques, including immunohistochemistry, UroVysion, and many molecular methods, have been employed to study the exact nature of this lesion. The aim of this review is to provide a comprehensive overview of the morphological and immunophenotypical aspects of UC-IGP. Moreover, we present and discuss the immunohistochemical and molecular markers involved in diagnosis and prognosis of UC-IGP lesions.

HER2-targeted therapies in gastric cancer

Molecular targeted therapy of cancer has always been the focus of clinicians. Among those therapeutic targets, the human epidermal growth factor receptor-2 (HER-2) signaling pathway is one of the most popular targets for translational research in cancer. However, unlike prospect in breast cancer, HER-2 inhibitor trastuzumab is the only molecular targeted drug approved by US Food and Drug Administration (FDA) for the first-line treatment of HER-2 positive advanced gastric cancer. On this basis, a variety of novel HER2- targeted drugs for gastric cancer are under development, and related clinical researches are in full swing, including small molecular kinase inhibitors (e.g., afatinib, neratinib, pyrotinib), antibody-drug conjugates (e.g., DS-8201a, RC48-ADC) and other novel therapies (e.g., ZW25, CAR-T, BVAC-B). In this study, we will summarize the recent advances in anti-HER-2 agents, potential mechanisms of resistance to HER2-targeted therapy in HER2-positive gastric cancer. We will also discuss the future prospects of potential strategies to overcome anti-HER-2 resistance and development of novel anti-HER-2 approaches for the treatment of HER2-positive gastric cancer patients.

Improvement of Targeted Chemotherapy of HER2-positive Ovarian Malignant Cell Line by ZHER2-Idarubicin Conjugate: An in vitro Study

Background & Objective:

Overexpression of human epidermal growth factor receptor 2 (HER2) causes cell transformation and development of various types of malignancies. Idarubicin is an effective anti-neoplastic drug but its specific delivery to the targeted cells is still a great challenge. Affibody as a cost-effective peptide molecule with low molecular weight has a high affinity for HER2 receptors. Breast and ovarian cancers as wide speared types of malignancies are associated with high expression of HER2. In the current study, we assessed the cytotoxic effects of idarubicin-Z_HER2 affibody conjugate on the positive-HER2 cancer cell lines.

Methods:

The cytotoxic effects of constructed idarubicin-Z_HER2 affibody conjugate on the SK-BR-3, SK-OV-3, and MCF-7 cells with various levels of HER2 expression were evaluated by MTT assay following 48 hours of incubation.

Results:

Idarubicin showed a potent and dose-dependent cytotoxic effect against all treated cell lines while the SK-OV-3 cells were significantly more sensitive. The dimeric form of the Z_HER2 affibody molecule showed a mild effect on the cell viability of all treated cells at its optimum concentration. The constructed Idarubicin-Z_HER2 affibody conjugate decreased the viability of SK-OV-3 cells at its optimal concentration, more efficiently and specifically than other treated cells.

Conclusion:

The Z_HER2-affibody conjugate of idarubicin has a more specific cytotoxic effect compared with idarubicin alone against HER2-overexpressing ovarian cancerous cells. It appears the Z_HER2-affibody conjugate of idarubicin has great potential to be implicated as an innovative anti-cancer agent in future clinical trials in patients with HER2-overexpressing ovarian cancer.

The Evolving Landscape of Antibody-Drug Conjugates for Urothelial Carcinoma

Metastatic urothelial carcinoma (UC) carries a poor prognosis and a 5-year overall survival of less than 5%, despite standard of care therapy using cisplatin-based chemotherapy and immune checkpoint inhibitors. Thus, novel agents that improve survival and have an acceptable toxicity profile are urgently needed. Antibody-drug conjugates (ADCs) represent a promising new treatment option that utilizes the targeting ability of an antibody to deliver cytotoxic drugs directly to tumors. Many ADCs are currently being investigated for treatment of UC, with enfortumab vedotin being recently approved by the US Food and Drug Administration for treatment of metastatic UC with progressive disease after chemotherapy and/or immune checkpoint inhibitors. Overall, ADCs hold promise as a long-awaited treatment option for UC.

Open-label, Multicenter, Phase II Study of RC48-ADC, a HER2-Targeting Antibody-Drug Conjugate, in Patients with Locally Advanced or Metastatic Urothelial Carcinoma

PURPOSE

To evaluate the efficacy and safety of RC48-ADC, a novel humanized anti-HER2 antibody conjugated with monomethyl auristatin E, in patients with HER2⁺ locally advanced or metastatic urothelial carcinoma (mUC) refractory to standard therapies.

PATIENTS AND METHODS

This was a phase II, open-label, multicenter, single-arm study of patients with HER2⁺ (IHC status 3+ or 2+) locally advanced or mUC who previously failed at least one line of systemic chemotherapy. The primary endpoint was the objective response rate (ORR) assessed by a blinded independent review committee (BIRC). The secondary endpoint included progression-free survival (PFS), disease control rate, duration of response, overall survival (OS), and safety.

RESULTS

Forty-three patients were enrolled. The median follow-up was 20.3 months. The overall confirmed ORR as assessed by the BIRC was 51.2% [95% confidence interval (CI), 35.5%-66.7%]. Similar responses were observed in prespecified subgroups, such as those with liver metastasis and those previously treated with anti-programmed cell death 1 (PD-1)/programmed death ligand 1 (PD-L1) therapies. The median PFS and OS were 6.9 months (95% CI, 5.6-8.9) and 13.9 months (95% CI, 9.1-NE), respectively. The most common treatment-related adverse events (TRAE) were hypoesthesia (60.5%), alopecia (55.8%), and leukopenia (55.8%). Twenty-five (58%) patients experienced grade 3 TRAEs, including hypoesthesia (23.3%) and neutropenia (14.0%). No grade 4 or grade 5 TRAEs occurred.

CONCLUSIONS

RC48-ADC demonstrated a promising efficacy with a manageable safety profile in patients with HER2⁺ locally advanced or mUC who had failed at least one line of systemic chemotherapy.

Human epidermal growth factor receptor 2 overexpression is frequently discordant between primary and metastatic urothelial carcinoma and is associated with intratumoral human epidermal growth factor receptor 2 heterogeneity

Human epidermal growth factor receptor 2 (HER2) overexpression occurs in 5-10% of primary urothelial carcinomas (UCs) but has not reliably predicted benefit from HER2-targeted agents in the metastatic setting. HER2 testing of primary tumors may not reflect the HER2 status of distant metastases. We assessed the concordance of HER2 expression in paired primary and distant metastatic UC lesions. Specimens from 149 patients with metastatic UC underwent immunohistochemical staining for HER2, including 79 paired primary and distant metastatic tumors. HER2 status was defined using 2018 ASCO/CAP guidelines. HER2 intratumoral heterogeneity (ITH) was defined as HER2 3+ expression in 5-50% of tumor cells. The HER2-positive, -equivocal, and -negative rates observed were 10.6%, 24.7%, and 64.7% for primary tumors and 9.8%, 12.6%, and 77.6% for metastatic tumors, respectively. HER2 ITH occurred in 44% of HER2-positive primary tumors. Low agreement of HER2-positive status between primary and metastatic tumors was observed (к = 0.193, P = 0.079). Loss of HER2 overexpression in the metastatic lesion was observed in 55% (5 of 9 cases) of HER2-positive primary cases and was associated with the presence of HER2 ITH in the primary tumor (Fisher's exact P = 0.048). Change from negative primary to positive metastasis was seen in 2% (1 of 50) of cases. No differences in metastasis-free survival or overall survival were observed in accordance with HER2 status defined by either the primary or metastatic lesion. These findings are likely to impact patient selection for HER2 targeted therapies in UC. Confirmation and evaluation of the clinical significance of HER2 discordance is warranted, preferably in the context of a clinical trial.

Human epidermal growth factor receptor 2 (HER2) gene amplification in non-muscle invasive urothelial bladder cancers: Identification of patients for targeted therapy

Objectives

To evaluate human epidermal growth factor receptor 2 (HER2) protein overexpression by immunohistochemistry (IHC) and gene amplification by fluorescent in situ hybridisation (FISH) in urothelial non-muscle-invasive bladder carcinoma (NMIBC), as HER2 is a potential therapeutic target in muscle-invasive bladder carcinoma (MIBC) and HER2 expression and gene amplification in low/high-grade and pTa/pT1 NMIBC is not clear.

Patients and methods

The study included 93 bladder cancers; 25 MIBC and 68 NMIBC (37 low- and 31 high-grade). All HER2 positive (3+) and equivocal (2+) cases were subjected to FISH using a HER2/CEN 17 dual-colour probe kit. IHC and FISH were scored as per the American Society of Clinical Oncology/College of American Pathologists (ASCO/CAP) 2013 Guidelines for breast cancers. Based on the number of signals/nuclei, amplification was categorised as low (≥6–10) and high-level (≥10).

Results

HER2 2–3+ expression was seen in 29% of NMIBCs (10.8% low- and 51.6% high-grade). HER2 3+ expression was seen in high-grade NMIBC (nine of 31; 29%) and MIBC (nine of 25; 36%). In all, 87% of high-grade NMIBCs were lamina invasive (pT1). Gene amplification was found in 45% (eight of 18) of 3+ tumours. None of the HER2 2+ tumours showed gene amplification. IHC and FISH results were in closest agreement when ≥50% of tumour cells showed 3+ expressions. High-level amplification correlated with increased gene expression on reverse transcriptase-polymerase chain reaction. On multivariate analysis, lower  stage, grade, and HER2 expression significantly correlated with progression-free survival. HER2 3+ expression in NMIBC correlated significantly with time to recurrence and progression.

Conclusion

Our present results show that HER2 FISH should not be performed for HER2 2 + and low-grade NMIBC. This contrasts with breast cancers where it is recommended for equivocal 2+ tumours. About 50% of HER2 3+ MIBC and high-grade NMIBC show HER2 gene amplification and can be potential candidates for HER2-targeted therapy.

Abbreviations

ASCO/CAP: American Society of Clinical Oncology/College of American Pathologists; DAB: 3,3ʹ-diaminobenzidine; FISH: fluorescent in situ hybridisation; HER2: human epidermal growth factor receptor 2; IHC: immunohistochemistry;(N)MIBC: (non-) muscle-invasive bladder carcinoma; MPUC: micropapillary variant of urothelial bladder cancer; PFS: progression-free survival; TURBT: transurethral resection of bladder tumour

Progressive plasmacytoid variant bladder cancer with retroperitoneal dissemination: An autopsy case report

INTRODUCTION

Plasmacytoid urothelial carcinoma is a rare and aggressive variant of bladder cancer.

CASE PRESENTATION

A 75-year-old woman presented with plasmacytoid urothelial carcinoma with retroperitoneal dissemination was treated with chemotherapy. After an unsuccessful first-line chemotherapy with gemcitabine and cisplatin, we assessed circulating tumor cells; one such cell was found to be positive for programmed death-ligand 1. The patient received second-line chemotherapy with pembrolizumab. However, the tumor extended to the retroperitoneal organs, and the patient eventually died. Autopsy revealed a widespread diffuse scirrhous infiltration of the carcinoma into the retroperitoneum. However, distant metastasis was not observed.

CONCLUSION

The evaluation of circulating tumor cells and autopsy revealed a disease state of progressive plasmacytoid urothelial carcinoma treated with pembrolizumab.

Oncogenic Addiction to ERBB2 Signaling Predicts Response to Trastuzumab in Urothelial Cancer

Urothelial carcinoma (UC) is a common and frequently lethal cancer. Despite the presence of genomic alterations creating dependency on particular signaling pathways, the use of targeted therapies in advanced and metastatic UC has been limited. We performed an integrated analysis of whole-exome and RNA sequencing of primary and metastatic tumors in a patient with platinum-resistant UC. We found a strikingly high ERBB2 mRNA expression and enrichment of downstream oncogenic ERBB2 signaling in this patient's tumors compared with tumors from an unselected group of patients with UC (N=17). This patient had an exceptional sustained response to trastuzumab. Our findings show that oncogenic addiction to ERBB2 signaling potentially predicts response to ERBB2-directed therapy of UC.

Response to Anti-HER2-Based Treatment in a Patient with Bladder Adenocarcinoma Harboring HER2 Amplification and S310F Mutation Discovered by Next-Generation Sequencing: A Case Report

Purpose

HER2 overexpression has been identified in approximately 14% of bladder adenocarcinomas. However, until now, there has been no approved standard targeted therapy for bladder adenocarcinoma patients harboring HER2 genetic alteration.

Case Presentation

We presented a case of a 64-year-old man who was diagnosed with bladder adenocarcinoma, and lung metastasis was confirmed less than one year after initial bladder surgery. The patient received systemic chemotherapy and antiangiogenetic treatment, but the tumor continued to progress. The patient underwent next-generation sequencing (NGS) to seek potential treatment opportunities. HER2 amplification, approximately 7 times, was discovered together with the S310F mutation (mutant abundance 90%). The patient then received late-line treatment with trastuzumab and albumin-bound paclitaxel. A partial response was confirmed two months later. Trastuzumab-based therapy was continued for 8 cycles, and the progression-free survival period was 6 months. NGS was performed on a rebiopsy, and the result showed no amplification of HER2, and the S310F mutant abundance was reduced to 27.9%.

Conclusion

This is the first case report describing a bladder adenocarcinoma patient harboring HER2 amplification who responded to trastuzumab. NGS is of great potential in the selection of bladder adenocarcinoma patients suitable for anti-HER2 therapy. The genetic change after treatment also implied possible mechanisms of resistance to trastuzumab-based therapy, which requires more investigation.

Immunohistochemical over-expression of HER2 does not always match with gene amplification in invasive bladder cancer

BACKGROUND

HER2 is a potential target of therapy in urothelial cancer (UC). Pathological case stratification according to HER2 gene amplification or HER2 protein overexpression was critical for patients' selection in previous unsuccessful clinical trial with HER2 targeting agents.

STUDY DESIGN

We evaluated the HER2 overexpression by immunohistochemistry (IHC) together with the amplification of the HER2 gene with chromogenic(CISH) and fluorescent (FISH) in situ hybridization in a cohort of 61 patients covering the whole spectrum of bladder UC variants, using a tissue microarray (TMA) approach.

RESULTS

IHC was available in all the 61 cases while ISH in 37 and FISH in 42. At IHC, 2/61 cases (3%) were scored 3+; 2 (3%) scored 2+; 2 (3%) scored 1+; the remaining 55 (91%) scored 0. At CISH analysis 10/37 cases (27%) were amplified, 6 cases with HER2 amplification showed positive HER2 IHC (3+, 2+, 1+). Seven cases with IHC score 0 were amplified at CISH. FISH analysis revealed an amplification in 5/42 cases (12%). The total number of HER2amplified cases was different between chromogenic and fluorescent ISH with 5 cases amplified using FISH compared to 10 with CISH.

CONCLUSIONS

In clinical trials with HER2 targeting agents the candidate patients should be investigated not only by IHC but also by ISH, independently of the IHC results. Since also usual type UC can overexpress HER2 we recommend to extend the patients' selection to all the histotypes of bladder cancer other than the micropapillary type.

Biomarkers predicting oncological outcomes of high-risk non-muscle-invasive bladder cancer

INTRODUCTION

The European Organization for Research and Treatment of Cancer (EORTC) and the Spanish Urological Club for Oncological Treatment (CUETO) scoring systems show limited accuracy for the prediction of disease recurrence and progression of non-muscle-invasive bladder cancer (NMIBC). This aspect is even more relevant in the category of HR NMIBC. Biomarkers might potentially help to further categorize the outcomes of these patients. Therefore, we sought to review the evidence available on tissue-based, urinary, and serum biomarkers for the prediction of recurrence, progression, and survival in HR NMIBC.

EVIDENCE ACQUISITION

A systematic literature review without time restrictions was performed using PubMed/EMBASE, Web of Science, SCOPUS, and the Cochrane Libraries. The search was filtered for articles in the English, Italian, German, French, and Spanish languages, involving patients with more than 18 years of age. Relevant papers on tissue-based, serum and urinary biomarkers related to the prediction of oncological outcomes for high-risk bladder cancer patients were included in the analyses.

EVIDENCE SYNTHESIS

Overall, 71 studies were eligible for inclusion in this review. The majority of the investigations performed so far focused on immunohistochemical analyses on tumoral tissue. Overall, p53 was the most studied biomarker, but results regarding its prognostic and predictive role were contradictory. Ki67 seems to be a promising biomarker in the prediction of recurrence. Recently, PD-L1 has been associated with the prediction of recurrence free survival and of treatment-refractory disease. Markers developed un urine samples are focused on commercially available kits, which currently do not unequivocally show strongly superior levels of accuracy to cytology. However, they have demonstrated to be potentially helpful in the prediction of recurrence. Blood-based biomarkers represent an emerging reality with promising future applications.

CONCLUSIONS

Despite a long history of attempts to discover accurate biomarkers predicting oncological outcomes for HR NMIBC, contradictory or uncertain findings render the adoption of this ancillary techniques in clinical practice still unlikely. Future attempts should be directed to the development of prospective trials and the definition of standardized cut-off levels to render findings worthy of comparison.

Multiparameter urine analysis for quantitative bladder cancer surveillance of orthotopic xenografted mice

The human-derived orthotopic xenograft mouse model is an effective platform for performing in vivo bladder cancer studies to examine tumor development, metastasis, and therapeutic effects of drugs. To date, the surveillance of tumor progression in real time for orthotopic bladder xenografts is highly dependent on semi-quantitative in vivo imaging technologies such as bioluminescence. While these imaging technologies can estimate tumor progression, they are burdened with requirements such as anesthetics, specialized equipment, and genetic modification of the injected cell line. Thus, a convenient and non-invasive technology to quantitatively monitor the growth of bladder cancer in orthotopic xenografts is highly desired. In this work, using a microfluidic chemiluminescent ELISA platform, we have successfully developed a rapid, multiparameter urine-based and non-invasive biomolecular prognostic technology for orthotopic bladder cancer xenografts. This method consists of two steps. First, the concentrations of a panel of four urinary biomarkers are quantified from the urine of mice bearing orthotopic bladder xenografts. Second, machine learning and principal component analysis (PCA) algorithms are applied to analyze the urinary biomarkers, and subsequently, a score is assigned to indicate the tumor growth. With this methodology, we have quantitatively monitored the orthotopic growth of human bladder cancer that was inoculated with low, medium, and high cancer cell numbers. We also employed this method and performed a proof of principle experiment to examine the in vivo therapeutic efficacy of the EGFR inhibitor, dacomitinib.

Complete response to trastuzumab and chemotherapy in recurrent urothelial bladder carcinoma with HER2 gene amplification: A case report

BACKGROUND

Targeted treatments may greatly affect the natural history of urothelial carcinoma based on their pharmacokinetics. A phase II trial has explored the combination of cytotoxic chemotherapy with the anti-HER-2 monoclonal antibody trastuzumab in selected patients with metastatic bladder cancer, but it failed.

CASE SUMMARY

Here, we report a case of recurrent urothelial bladder carcinoma (UBC) in a patient who has undergone three operations, and further illuminate its diagnosis and treatment. The diagnosis of UBC was rendered according to the pathological indices. Next-generation sequencing on formalin fixed paraffin-embedded (FFPE) tissue was also performed and suggested HER2 gene amplification in the FFPE tissue. Based on HER2 gene amplification in FFPE, the patient was treated with chemotherapy in combination with trastuzumab after his third surgery. Fortunately, the patient got a clinically complete remission to trastuzumab for 34 mo.

CONCLUSION

There is not enough clinical evidence for incorporating trastuzumab in routine treatment of UBC. This case hinted that recurrent UBC patients with HER2 gene amplification may benefit from targeted trastuzumab. Further studies are needed to further investigate the status of HER2 gene and better determine trastuzumab in the management of UBC.

ErbB2 Copy Number Aberration in Canine Urothelial Carcinoma Detected by a Digital Polymerase Chain Reaction Assay

Urothelial carcinoma (UC) is the most common tumor affecting the urinary bladder of dogs. Protein overexpression of ErbB2 (the canine homolog of HER2) has been observed in dogs with UC. However, no study regarding ErbB2 copy number aberration (CNA) is reported in dogs with UC. In this study, a digital PCR assay for detecting CNA of canine ErbB2 was developed. DNA samples were isolated from 83 formalin-fixed, paraffin-embedded urinary bladder tissues (36 UC, 8 polypoid cystitis, and 39 normal) and 94 urinary sediments (54 UC, 30 nonneoplastic, and 10 normal). The copy number of canine chromosome 8 (CFA8) was used as a control. In the urinary bladder tissues, ErbB2 CNA was detected in 12 of 36 (33%) UC, 2 of 8 (25%) polypoid cystitis, and 0 of 39 (0%) normal controls. In the urinary sediments, ErbB2 CNA was also detected in 19 of 54 (35%) UC; however, no ErbB2 CNA was detected in nonneoplastic diseases or normal controls. The sensitivity and specificity of ErbB2 CNA in urinary sediment for the detection of UC were 35% and 100%, respectively. There was a positive correlation between the copy number ratios of ErbB2 to CFA8 in the urinary bladder tissues and urinary sediments. Our findings indicate that the digital PCR assay of urinary sediments may be a useful, noninvasive method for detecting ErbB2 CNA in dogs with UC.

Prognostic and therapeutic role of HER2 expression in micropapillary carcinoma of the bladder

Micropapillary carcinoma of the bladder (MPBC) is a variant type of infiltrating urothelial carcinoma, which portends a poor biological behavior in terms of disease stage at first diagnosis and clinical outcome; its peculiar morphology raises issues concerning the ability of tumor detection by imaging techniques and proper biopsy procedure, and the appropriate treatment for non-muscle infiltrating and muscle-infiltrating MPBC remains a matter of debate. On the basis of its established prognostic and therapeutic role in breast and gastro-esophageal cancer in the first instance, the human epidermal growth factor receptor-2 (HER2) has been investigated in selected case series of MPBC over the last 10 years. The aim of the present review was to summarize the existing evidence on HER2 status in MPBC, and to discuss its present and future utility in risk assessment and treatment choice of this uncommon, yet aggressive, disease.

Fatty acid synthase, Her2/neu, and E2F1 as prognostic markers of progression in non-muscle invasive bladder cancer

Non-muscle-invasive bladder cancer (NMIBC) is a heterogeneous disease which has an unpredictable risk of progression to muscle-invasive bladder cancer (MIBC). The selection of patients who may benefit from early radical intervention is a challenge. To define the useful prognostic markers for progression, we analyzed the immunohistochemical expression of fatty acid synthase (FASN), Her2/neu, and E2F1 in 60 cases of NMIBC who underwent TURBT and adjuvant intravesical bacillus-Calmette-Guérin (BCG). Their predicting role for tumor recurrence, progression, recurrence-free survival (RFS) and progression-free survival (PFS) was analyzed. High FASN expression was observed in 56.7% (34/60) of NMIBC cases, and FASN expression was significantly associated with the tumor size, grade, and tumor stage (p = 0.003, p < 0.001, p < 0.0001 respectively). Positive Her2/neu was noted in 18.3% (11/60) of the cases, and its expression was significantly associated with the tumor size, histologic grade, and tumor stage (p = 0.001, p = 0.002, p = 0.011 respectively). High E2F1 expression was detected in 40% of the cases, and it was associated with tumor size, histologic grade, and tumor stage (p < 0.001 for each). Analysis of follow-up period revealed that NMIBC with high FASN, positive Her2/neu, and high E2F1 expression exhibited a potent relation with tumor progression, shorter RFS, and poor PFS. Conclusions: High FASN, Her2/neu, and E2F1 are considered as adverse prognostic factors of tumor recurrence and progression in NMIBC and these patients should be followed carefully. Therefore, we suggest that FASN, Her2/neu, and E2F1 should be considered and evaluated during the selection of the appropriate management strategy for NMIBC patients.

Assessment of HER2 Expression in Canine Urothelial Carcinoma of the Urinary Bladder

Canine urothelial carcinoma (UC) has a poor prognosis and high metastatic rate. Human epidermal growth factor receptor 2 (HER2), a receptor tyrosine kinase involved in cell proliferation and differentiation regulation, has been attracting interest as a therapeutic target molecule for human breast cancer. This study investigated expression of the canine homolog of HER2 (ERBB2) in canine UC, and its association with clinical factors. Since it has been controversial whether commercial anti-human HER2 antibody (Dako A0485) correctly recognizes the canine homolog of HER2, an application of the antibody using a canine UC cell line was validated first. By Western blot, a single band at the appropriate size for canine HER2 (185 kDa) was recognized. Immunohistochemistry for HER2 was performed on 23 samples of UC, 8 samples of polypoid cystitis, and 8 samples of normal urinary bladder, and the results were scored as either 0, 1+, 2+, or 3+ with reference to the evaluation method for human UC. Intense membranous HER2 immunoreactivity was frequently observed in neoplastic cells, especially in grade 2 UC. Minor HER2 expression was found in the epithelial cells of polypoid cystitis and normal bladder. The incidence of HER2 positivity (scores of 2+ or 3+) was 14 of 23 (60.9%) in UC, 3 of 8 (37.5%) in polypoid cystitis, and 0 of 8 (0%) in normal bladder. There was no significant correlation between HER2 positivity and clinical factors. While increased HER2 expression was observed in a subset of urothelial carcinomas, further mechanistic studies are needed to determine its role in the pathogenesis and targeted therapy of this cancer.

Serine/threonine kinase 32C is overexpressed in bladder cancer and contributes to tumor progression

Tumor markers of bladder cancer (BC) have been investigated for many years, but the clinical treatment based on these biomarkers is still unsatisfactory. STK32C, a member of the serine/threonine protein kinase of AGC superfamily, was first found to be highly expressed in brain tissues; however, the role of STK32C in malignant disease has not been determined. Data from TCGA database showed that the STK32C gene is overexpressed in BC and a number of other human tumors. In the current study, immunohistochemistry revealed that high expression of STK32C protein in tumor tissues was significantly associated with poor clinico pathologic features and a short relapse-free survival (RFS) in patients with BC. Slicing of STK32C inhibited tumor cell proliferation, migration and invasion in vitro. In vivo animal experiments demonstrated that knocking-down of STK32C restricted the growth of tumor cells in mice. Finally, microarray analysis revealed that silencing of STK32C inhibited the activity of the HMGB1 pathway and regulated the expression of key genes in this pathway. In conclusion, our study showed novel promoting roles for STK32C in human tumors, which may provide a new therapeutic target for the patients with BC.

Reappraisal of HER2 status in the spectrum of advanced urothelial carcinoma: a need of guidelines for treatment eligibility

Although human epidermal growth factor receptor 2 (HER2) may represent a therapeutic target, its evaluation in urothelial carcinoma of the bladder does not rely on a standardized scoring system by immunohistochemistry or fluorescent in situ hybridization (FISH), as reflected by various methodology in the literature and clinical trials. Our aim was to improve and standardize HER2 amplification detection in bladder cancer. We assessed immunohistochemical criteria derived from 2013 American Society of Clinical Oncology (ASCO)/College of American Pathologists (CAPs) guidelines for breast cancer and investigated intratumoral heterogeneity in a retrospective multicentric cohort of 188 patients with locally advanced urothelial carcinoma of the bladder. Immunohistochemistry was performed on 178 primary tumors and 126 lymph node metastases, eligible cases (moderate/strong, complete/incomplete membrane staining) were assessed by FISH. HER2 overexpression was more frequent with 2013 ASCO/CAP than 2007 ASCO/CAP guidelines (p < 0.0001). The rate of positive HER2 FISH was similar between primary tumor and lymph node metastases (8%). Among positive FISH cases, 48% were associated with moderate/strong incomplete membrane staining that were not scored eligible for FISH by 2007 ASCO/CAP criteria. Among 3+ immunohistochemistry score cases, 67% were associated with HER2-positive FISH. Concordance between primary tumors and matched lymph node metastases was moderate for immunohistochemistry (κ = 0.54 (CI 95%, 0.41-0.67)) and FISH (κ = 0.50 (CI 95%, 0.20-0.79)). HER2-positive FISH was more frequent in micropapillary carcinomas (12%) and carcinoma with squamous differentiation (11%) than in pure conventional carcinoma (6%). Intratumoral heterogeneity for HER2 immunohistochemistry was observed in 7% primary tumor and 6% lymph node metastases; 24% positive HER2 FISH presented intratumoral heterogeneity. Our study suggests that HER2 evaluation should include an immunohistochemistry screening step with eligibility for FISH including incomplete/complete and moderate/strong membrane staining. Spatial or temporal intratumoral heterogeneity prompts to perform evaluation on both tumor and lymph node, and for each histological variant observed.