Molecular targets on the horizon for kidney and urothelial cancer

Assessment of survivin and p27 expression as potential prognostic markers in urothelial cell carcinoma of urinary bladder in Egyptian patients

Background

Bladder cancer (BC) is the tenth most common cancer worldwide with urothelial carcinoma (UC) being the main histologic subtype. Survivin is an apoptosis inhibitor that is associated with tumor proliferation and invasion. P27 is a cyclin-dependent kinase inhibitor that negatively regulates cell proliferation. The expression of both proteins was variable among different solid tumors including UC.

Methods

We aimed to investigate the expression of survivin and P27 in UC of urinary bladder and correlate their expressions with histopathological parameters in an attempt at studying the possibility of their use as targeted therapies. The investigation was performed through immunohistochemical staining for both proteins on sections belonging to 60 UCs and 12 mild chronic cystitis cases (controls). Immunopositivity (number of positive cases) and expression score (percentage of positive urothelial cells) were evaluated.

Results

Both survivin and P27 were absent in urothelial cells of mild chronic cystitis lesions while expressed in 60% and 43.3% of UCs, respectively. High score of survivin and low score of P27 were associated with poor prognostic factors of UC (solid pattern, high grade, and deep tumors). By logistic regression test, survivin expression can be a predictive risk factor associated with solid pattern and high-grade UC, while P27 expression can be a predictive risk factor associated low-grade UC.

Conclusion

High survivin and low P27 expression scores were associated with the studied prognostic factors of UC. Both proteins may play a role in UC progression and can have a value as prognostic and/or diagnostic markers of UC, as well as targeted therapies.

Morphological spectrum of renal cell carcinoma, unclassified: an analysis of 136 cases

AIMS

Renal cell carcinoma, unclassified (RCCU) is a category that includes a morphologically and biologically heterogeneous group of tumours that are unable to be diagnosed as other well-defined entities. We aim to describe the morphological findings of tumours within this category and to determine the most frequent morphological features leading to classification difficulty.

METHODS AND RESULTS

One hundred and thirty-six cases of RCCU were examined. Patients ranged in age from 23 to 87 years. Seventy-seven patients were men and 59 were women. International Society of Urological Pathology (ISUP) grade was most commonly 3 (n = 66), followed by 2 (n = 42) and 4 (n = 28). Tumour size ranged from 0.6 to 24.9 cm. The American Joint Committee on Cancer (AJCC) pathological T categories included pT1a (n = 50), pT1b (n = 14), pT2a (n = 7), pT2b (n = 4), pT3a (n = 50) and pT4 (n = 9). Forty-four cases included lymph node(s), 41% of which (n = 18) had metastases. Tumours were assessed for a variety of histological features and assigned to the following morphological groups: predominantly oncocytoma/chromophobe RCC-like; clear cell RCC-like; papillary RCC-like; collecting duct-like; and pure sarcomatoid differentiation. The majority of the oncocytoma/chromophobe and clear cell RCC-like phenotypes were low stage (pT1 or pT2). The papillary RCC-like, collecting duct-like and pure sarcomatoid phenotypes were mainly high stage (pT3 or pT4).

CONCLUSIONS

Renal cell carcinoma, unclassified is a term that encompasses tumours with a variety of morphological features and a wide biological spectrum. The most common source of diagnostic difficulty was tumours composed of predominantly eosinophilic cells.

Toward personalized management in bladder cancer: the promise of novel molecular taxonomy

Empowered by the recent advances in next generation sequencing and bioinformatics technology, an unprecedented wave of integrated transcriptomic and genomic studies have impacted the field of bladder cancer. These studies not only have confirmed previously charted genetic pathways in bladder cancer development but also have led to the discovery of numerous additional crucial driver genetic alterations. As a result, a novel genomic-based taxonomy is emerging that promises to better define clinically relevant intrinsic subtypes of bladder cancer. The current review is an update on the above advances and their significant implications on the future of bladder cancer patient management.

The Wide Experience of the Sequential Therapy for Patients with Metastatic Renal Cell Carcinoma

Sequential targeted therapies are the standard of care for patients with metastatic renal cell carcinoma (mRCC). Several drugs are available for patients whose disease progresses while they receive initial tyrosine kinase inhibitor (TKI) therapy; these include nivolumab (an inhibitor of PD-1 receptor), everolimus (an inhibitor of the mechanistic target of rapamycin) or additional TKIs. Until now, there has been no clinical evidence to support the use of one strategy versus another, so investigators and physicians rely on experience, judgement and findings from molecular analyses to select the appropriate treatment. However, with the arrival of nivolumab and cabozantinib that provide an overall survival higher than other alternative treatments, therapeutic strategies may have changed. Here, we discuss findings from preclinical and clinical studies that might help clinicians to choose the optimal treatment approach for patients with mRCC who progress to initial therapy.

Aberrantly expressed microRNAs in bladder cancer and renal cell carcinoma

Bladder cancer (BC) and renal cell carcinoma (RCC) are frequently diagnosed urinary tract cancers. Recently developed molecular-targeted therapies for RCC have shown remarkable therapeutic efficacy; however, no targeted therapeutics are currently approved for the treatment of BC, and few effective treatment options exist. Current studies have shown that small noncoding RNA molecules have major roles in cancer cells. MicroRNAs (miRNAs) are endogenous small noncoding RNA molecules that regulate protein-/nonprotein-coding RNAs in human cells. A large body of evidence suggests that aberrantly expressed miRNAs are deeply involved in the pathogenesis of human cancers. In this paper, we review recently published miRNA expression signatures of BC and RCC. We focus on downregulated or upregulated miRNAs in multiple signatures and discuss putative target genes of miRNAs. Comparisons of RCC and BC expression signatures revealed that the two types of cancer showed opposite expression patterns for miR-200 family miRNAs (i.e., miR-141/200c and miR-200a/200b/429). We discuss in silico analysis of genes targeted by miR-200 family miRNAs and the molecular mechanisms underlying BC and RCC.

Emerging Bladder Cancer Biomarkers and Targets of Therapy

Bladder cancer is a heterogeneous disease characterized by complex networks of molecular alterations and gene expression. This review summarizes some of the recent genomic studies that have further advanced the understanding of the pathways driving bladder cancer, highlighting several important biomarkers and potential targeted therapeutic strategies that are now in clinical trials. In addition, noninvasive techniques to evaluate biomarkers in patients' urine and serum for early detection and surveillance are discussed.

The role of genomics in the management of advanced bladder cancer

OPINION STATEMENT

Advanced bladder cancer (ABC) is an aggressive malignancy with a poor prognosis. For the last 30 years, the standard of care for this disease has consisted of combination chemotherapy with a platinum-containing regimen as first-line therapy. Cisplatin is the most active cytotoxic agent against bladder cancer, but because of competing comorbidities, many patients are ineligible for this agent and instead receive carboplatin. The two-drug regimen of cisplatin and gemcitabine was found to be better tolerated and have comparable efficacy as the four-drug regimen of methotrexate, vinblastine, doxorubicin, and cisplatin (MVAC) in a randomized study of patients with advanced disease. Therefore, cisplatin (or carboplatin) and gemcitabine is the most commonly used first-line regimen in this setting. No agents have been approved by the Food and Drug Administration (FDA) for second-line therapy in ABC. If patients are eligible for additional systemic treatment at the time of progression, options include single-agent therapy such as a taxane or pemetrexed, though given the lack of standard approaches participation in a clinical trial should be strongly encouraged. Recent molecular characterization of ABC reveals significant genetic heterogeneity and actionable genomic alterations in the majority of tumors. Emerging therapies may effectively target known molecular drivers of ABC, including the FGFR2, EGFR/HER2, VEGF, MET, and PI3/AKT/mTOR pathways. Reports of dramatic and prolonged responses to targeted therapy provide additional support for the use of genome sequencing in the rationale selection of treatment for subsets of patients. The current focus of clinical trial development is to design molecularly driven studies that "match" tumors with driver mutations and appropriate targeted therapies rather than a "one-size-fits-all" approach based on clinical and pathologic parameters of disease. The hope of patients and clinicians alike is that this therapeutic approach combined with novel agents may usher in a new era of effective treatments for patients with ABC.

Elevating the Horizon: Emerging Molecular and Genomic Targets in the Treatment of Advanced Urothelial Carcinoma

Despite recent advances in the identification of genomic alterations that lead to urothelial oncogenesis in vitro, patients with advanced urothelial carcinomas continue to have poor clinical outcomes. In the present review, we focus on targeted therapies that have yielded the most promising results alone or combined with traditional chemotherapy, including the antiangiogenesis agent bevacizumab, the human epidermal growth factor receptor 2 antibody trastuzumab, and the tyrosine kinase inhibitor cabozantinib. We also describe ongoing and developing clinical trials that use innovative approaches, including dose-dense scheduling of singular chemotherapy combinations, prospective screening of tumor tissues for mutational targets and biomarkers to predict chemosensitivity before the determination of the therapeutic regimen, and novel agents that target proteins in the immune checkpoint regulation pathway (programmed cell death protein 1 [PD-1] and anti-PD-ligand 1) that have shown significant potential in preclinical models and early clinical trials. New agents and targeted therapies, alone or combined with traditional chemotherapy, will only be validated through accrual to developing clinical trials that aim to translate these therapies into individualized treatments and improved survival rates in urothelial carcinoma.

Altered FGF Signaling Pathways Impair Cell Proliferation and Elevation of Palate Shelves

In palatogenesis, palatal shelves are patterned along the mediolateral axis as well as the anteroposterior axis before the onset of palatal fusion. Fgf10 specifically expressed in lateral mesenchyme of palate maintains Shh transcription in lateral epithelium, while Fgf7 activated in medial mesenchyme by Dlx5, suppressed the expansion of Shh expression to medial epithelium. How FGF signaling pathways regulate the cell behaviors of developing palate remains elusive. In our study, we found that when Fgf8 is ectopically expressed in the embryonic palatal mesenchyme, the elevation of palatal shelves is impaired and the posterior palatal shelves are enlarged, especially in the medial side. The palatal deformity results from the drastic increase of cell proliferation in posterior mesenchyme and decrease of cell proliferation in epithelium. The expression of mesenchymal Fgf10 and epithelial Shh in the lateral palate, as well as the Dlx5 and Fgf7 transcription in the medial mesenchyme are all interrupted, indicating that the epithelial-mesenchymal interactions during palatogenesis are disrupted by the ectopic activation of mesenchymal Fgf8. Besides the altered Fgf7, Fgf10, Dlx5 and Shh expression pattern, the reduced Osr2 expression domain in the lateral mesenchyme also suggests an impaired mediolateral patterning of posterior palate. Moreover, the ectopic Fgf8 expression up-regulates pJak1 throughout the palatal mesenchyme and pErk in the medial mesenchyme, but down-regulates pJak2 in the epithelium, suggesting that during normal palatogenesis, the medial mesenchymal cell proliferation is stimulated by FGF/Erk pathway, while the epithelial cell proliferation is maintained through FGF/Jak2 pathway.

Emerging concepts on drug resistance in bladder cancer: Implications for future strategies

The combination chemotherapies with methotrexate plus vinblastine, doxorubicin and cisplatin (MVAC or CMV regimens) or gemcitabine plus cisplatin represent the standard as first-line therapy for patients with metastatic urothelial cancer. In Europe, vinflunine is an option for second-line therapy for patients progressed during first-line or perioperative platinum-containing regimen. Alternative regimens containing taxanes and/or gemcitabine may be valuated case by case. Furthermore, carboplatin should be considered in patients unfit for cisplatin both in the first and second-line setting. Based on these findings, a better comprehension of the mechanisms underlying the development of drug resistance in patients with bladder cancer will represent a major step forward in optimizing patients' outcome. This article reviews the current knowledge of the mechanisms and emerging strategies to overcome resistance in patients with advanced urothelial cancer.

MEK and PI3K inhibition in solid tumors: rationale and evidence to date

PI3K-AKT-mTOR and Ras-Raf-MEK-ERK are the most commonly altered oncogenic pathways in solid malignancies. There has been a lot of enthusiasm to develop inhibitors to these pathways for cancer therapy. Unfortunately, the antitumor activities of single-agent therapies have generally been disappointing, excluding B-Raf mutant melanoma and renal cell cancer. Preclinical studies have suggested that concurrent targeting of the PI3K-AKT-mTOR and Ras-Raf-MEK-ERK pathways is an active combination in various solid malignancies. In the current work, we review the preclinical data of the PI3K and MEK dual targeting as a cancer therapy and the results of early-phase clinical trials, and propose future directions.

Variation in genomic landscape of clear cell renal cell carcinoma across Europe

The incidence of renal cell carcinoma (RCC) is increasing worldwide, and its prevalence is particularly high in some parts of Central Europe. Here we undertake whole-genome and transcriptome sequencing of clear cell RCC (ccRCC), the most common form of the disease, in patients from four different European countries with contrasting disease incidence to explore the underlying genomic architecture of RCC. Our findings support previous reports on frequent aberrations in the epigenetic machinery and PI3K/mTOR signalling, and uncover novel pathways and genes affected by recurrent mutations and abnormal transcriptome patterns including focal adhesion, components of extracellular matrix (ECM) and genes encoding FAT cadherins. Furthermore, a large majority of patients from Romania have an unexpected high frequency of A:T>T:A transversions, consistent with exposure to aristolochic acid (AA). These results show that the processes underlying ccRCC tumorigenesis may vary in different populations and suggest that AA may be an important ccRCC carcinogen in Romania, a finding with major public health implications.

Overcoming tumor heterogeneity in the molecular diagnosis of urological cancers

Our understanding of tumor heterogeneity and impact on treatment response is still in its infancy, presenting significant challenges to the molecular pathologist, treating physician and ultimately for the patient. Given that tumor recurrence due to treatment resistance is the most common cause of cancer death, there remains a critical unmet need to change the current paradigm. The mechanisms which underlie tumor heterogeneity can be broadly divided into genomic instability and non-mutational processes, including stochastic variations in cellular responses, modulation by tumor microenvironment and or phenotypic/ functional plasticity relating to cancer stem cells. We believe that these biological mechanisms are not mutually exclusive and emphasize the need for more suitable methodologies to exploit the spatiotemporal patterns of intratumoral heterogeneity using novel approaches such as quantitative tissue-based biomarker assessment and systemic fluid analytics. Generating a comprehensive patient-centric phenotypic disease profile should generate a 'codex' which can be employed to change the current treatment decision process.

Molecular profiling of infiltrating urothelial carcinoma of bladder and nonbladder origin

BACKGROUND

Infiltrating UC represents the second most common genitourinary malignancy. Advanced UC has a poor prognosis and new treatments are needed. Molecular profiling of UC might identify biomarkers associated with targeted therapies or chemotherapeutics, providing physicians with new treatment options.

MATERIALS AND METHODS

Five hundred thirty-seven cases of locally advanced or metastatic UC of the bladder, 74 nonbladder, and 55 nonurothelial bladder cancers were profiled using mutation analysis, in situ hybridization, and immunohistochemistry assays for biomarkers predictive of therapy response.

RESULTS

Molecular profiling of UC showed high overexpression of topoisomerase 2α, common phosphatidylinositol-4,5-bisphosphate 3-kinase, catalytic subunit alpha and/or phosophatase and tensin homolog (PTEN) alterations in nonbladder (27%) and bladder UC (21%), and rare gene mutations across subtypes. Compared with nonbladder, bladder UC consistently exhibited more frequent abnormal protein expression, including HER2 (10% vs. 3%; P = .04), tyrosine protein c-Kit receptor kinases (11% vs. 5%), c-Met proto-oncogene, receptor tyrosine kinases (25% vs. 8%), androgen receptor (16% vs. 6%), O(6)-methylguanine-methyltransferase (63% vs. 43%), ribonucleotide reductase M1 (32% vs. 11%), Serum protein acidic and rich in cysteine (SPARC) (69% vs. 33%), and topoisomerase 1 (63% vs. 39%). Bladder UC also exhibited increased amplification of HER2 (12% vs. 2%; P = .06).

CONCLUSION

Comprehensive molecular profiling of UC identified a large number of biomarkers aberrations that might direct treatment in conventional chemotherapies and targeted therapies, not currently recommended in this population. As a group, bladder UC exhibited higher levels of actionable biomarkers, suggesting that UC from different primary sites and non-UC are driven by different molecular pathways. These differences could have clinical implications resulting in different treatment regimens depending on the site of origin of UC.