BRCA1 loss preexisting in small subpopulations of prostate cancer is associated with advanced disease and metastatic spread to lymph nodes and peripheral blood

Case report: Squamous cell carcinoma of the prostate-a clinicopathological and genomic sequencing-based investigation

Squamous differentiation of prostate cancer, which accounts for less than 1% of all cases, is typically associated with androgen deprivation treatment (ADT) or radiotherapy. This entity is aggressive and exhibits poor prognosis due to limited response to traditional treatment. However, the underlying molecular mechanisms and etiology are not fully understood. Previous findings suggest that squamous cell differentiation may potentially arise from prostate adenocarcinoma (AC), but further validation is required to confirm this hypothesis. This paper presents a case of advanced prostate cancer with a combined histologic pattern, including keratinizing SCC and AC. The study utilized whole-exome sequencing (WES) data to analyze both subtypes and identified a significant overlap in driver gene mutations between them. This suggests that the two components shared a common origin of clones. These findings emphasize the importance of personalized clinical management for prostate SCC, and specific molecular findings can help optimize treatment strategies.

Detection and Characterization of Circulating Tumor Cells Using Imaging Flow Cytometry—A Perspective Study

Simple Summary

Liquid biopsy is non-invasive approach used to prognose and monitor tumor progression based on the detection and examination of metastasis-related events found in the patients’ blood (such as circulating tumor cells (CTCs), extracellular vesicles, and circulating nucleic acids). Different ultrasensitive techniques are applied to study those events and the biology of tumor dissemination, which in the future might complement standard diagnostics. Here, we suggest that CTCs analysis could be improved by the usage of imaging flow cytometry, combining advantages of both standard flow cytometry (high-scale analysis) and microscopy (high resolution) to investigate detailed features of those cells. From this perspective, we discuss the potential of this technology in the CTC field and present representative images of CTCs from breast and prostate cancer patients analyzed with this method.

Abstract

Tumor dissemination is one of the most-investigated steps of tumor progression, which in recent decades led to the rapid development of liquid biopsy aiming to analyze circulating tumor cells (CTCs), extracellular vesicles (EVs), and circulating nucleic acids in order to precisely diagnose and monitor cancer patients. Flow cytometry was considered as a method to detect CTCs; however, due to the lack of verification of the investigated cells’ identity, this method failed to reach clinical utility. Meanwhile, imaging flow cytometry combining the sensitivity and high throughput of flow cytometry and image-based detailed analysis through a high-resolution microscope might open a new avenue in CTC technologies and provide an open-platform system alternative to CellSearch^®, which is still the only gold standard in this field. Hereby, we shortly review the studies on the usage of flow cytometry in CTC identification and present our own representative images of CTCs envisioned by imaging flow cytometry providing rationale that this novel technology might be a good tool for studying tumor dissemination, and, if combined with a high CTC yield enrichment method, could upgrade CTC-based diagnostics.

BRCA Mutations in Ovarian and Prostate Cancer: Bench to Bedside

Simple Summary

DNA damage is one of the hallmarks of cancer. Epithelial ovarian cancer (EOC) —especially the high-grade serous subtype—harbors a defect in at least one DNA damage response (DDR) pathway. Defective DDR results from a variety of lesions affecting homologous recombination (HR) and nonhomologous end joining (NHEJ) for double strand breaks, base excision repair (BER), and nucleotide excision repair (NER) for single strand breaks and mismatch repair (MMR). Apart from the EOC, mutations in the DDR genes, such as BRCA1 and BRCA2, are common in prostate cancer as well. Among them, BRCA2 lesions are found in 12% of metastatic castration-resistant prostate cancers, but very rarely in primary prostate cancer. Better understanding of the DDR pathways is essential in order to optimize the therapeutic choices, and has led to the design of biomarker-driven clinical trials. Poly(ADP-ribose) polymerase (PARP) inhibitors are now a standard therapy for EOC patients, and more recently have been approved for the metastatic castration-resistant prostate cancer with alterations in DDR genes. They are particularly effective in tumours with HR deficiency.

Abstract

DNA damage repair (DDR) defects are common in different cancer types, and these alterations can be exploited therapeutically. Epithelial ovarian cancer (EOC) is among the tumours with the highest percentage of hereditary cases. BRCA1 and BRCA2 predisposing pathogenic variants (PVs) were the first to be associated with EOC, whereas additional genes comprising the homologous recombination (HR) pathway have been discovered with DNA sequencing technologies. The incidence of DDR alterations among patients with metastatic prostate cancer is much higher compared to those with localized disease. Genetic testing is playing an increasingly important role in the treatment of patients with ovarian and prostate cancer. The development of poly (ADP-ribose) polymerase (PARP) inhibitors offers a therapeutic strategy for patients with EOC. One of the mechanisms of PARP inhibitors exploits the concept of synthetic lethality. Tumours with BRCA1 or BRCA2 mutations are highly sensitive to PARP inhibitors. Moreover, the synthetic lethal interaction may be exploited beyond germline BRCA mutations in the context of HR deficiency, and this is an area of ongoing research. PARP inhibitors are in advanced stages of development as a treatment for metastatic castration-resistant prostate cancer. However, there is a major concern regarding the need to identify reliable biomarkers predictive of treatment response. In this review, we explore the mechanisms of DDR, the potential for genomic analysis of ovarian and prostate cancer, and therapeutics of PARP inhibitors, along with predictive biomarkers.

New horizons in the identification of circulating tumor cells (CTCs): An emerging paradigm shift in cytosensors

Circulating tumor cells (CTCs) are cancer cells that are shed from a primary tumor into the bloodstream and function as seeds for cancer metastasis at distant locations. Enrichment and identification methods of CTCs in the blood of patients plays an important role in diagnostic assessments and personalized treatments of cancer. However, the current traditional identification methods not only impact the viability of cells, but also cannot determine the type of cancer cells when the disease is unknown. Hence, new methods to identify CTCs are urgently needed. In this context, many advanced and safe technologies have emerged to distinguish between cancer cells and blood cells, and to distinguish specific types of cancer cells. In this review, at first we have briefly discussed recent advances in technologies related to the enrichment of CTCs, which lay a good foundation for the identification of CTCs. Next, we have summarized state-of-the-art technologies to confirm whether a given cell is indeed a tumor cell and determine the type of tumor cell. Finally, the challenges for application and potential directions of the current identification methods in clinical analysis of CTCs have been discussed.

BRCA Mutations in Prostate Cancer: Assessment, Implications and Treatment Considerations

Prostate cancer ranks fifth in cancer-related mortality in men worldwide. DNA damage is implicated in cancer and DNA damage response (DDR) pathways are in place against this to maintain genomic stability. Impaired DDR pathways play a role in prostate carcinogenesis and germline or somatic mutations in DDR genes have been found in both primary and metastatic prostate cancer. Among these, BRCA mutations have been found to be especially clinically relevant with a role for germline or somatic testing. Prostate cancer with DDR defects may be sensitive to poly(ADP-ribose) polymerase (PARP) inhibitors which target proteins in a process called PARylation. Initially they were used to target BRCA-mutated tumor cells in a process of synthetic lethality. However, recent studies have found potential for PARP inhibitors in a variety of other genetic settings. In this review, we explore the mechanisms of DNA repair, potential for genomic analysis of prostate cancer and therapeutics of PARP inhibitors along with their safety profile.

Low Tumor-to-Stroma Ratio Reflects Protective Role of Stroma against Prostate Cancer Progression

Tumor-to-stroma ratio (TSR) is a prognostic factor that expresses the relative amounts of tumor and intratumoral stroma. In this study, its clinical and molecular relevance was evaluated in prostate cancer (PCa). The feasibility of automated quantification was tested in digital scans of tissue microarrays containing 128 primary tumors from 72 PCa patients stained immunohistochemically for epithelial cell adhesion molecule (EpCAM), followed by validation in a cohort of 310 primary tumors from 209 PCa patients. In order to investigate the gene expression differences between tumors with low and high TSR, we applied multigene expression analysis (nCounter® PanCancer Progression Panel, NanoString) of 42 tissue samples. TSR scores were categorized into low (<1 TSR) and high (≥1 TSR). In the pilot cohort, 31 patients (43.1%) were categorized as low and 41 (56.9%) as high TSR score, whereas 48 (23.0%) patients from the validation cohort were classified as low TSR and 161 (77.0%) as high. In both cohorts, high TSR appeared to indicate the shorter time to biochemical recurrence in PCa patients (Log-rank test, p = 0.04 and p = 0.01 for the pilot and validation cohort, respectively). Additionally, in the multivariate analysis of the validation cohort, TSR predicted BR independent of other factors, i.e., pT, pN, and age (p = 0.04, HR 2.75, 95%CI 1.07-7.03). Our data revealed that tumors categorized into low and high TSR score show differential expression of various genes; the genes upregulated in tumors with low TSR score were mostly associated with extracellular matrix and cell adhesion regulation. Taken together, this study shows that high stroma content can play a protective role in PCa. Automatic EpCAM-based quantification of TSR might improve prognostication in personalized medicine for PCa.

Mutations in TP53 or DNA damage repair genes define poor prognostic subgroups in primary prostate cancer

BACKGROUND

Mutations in DNA damage repair genes, in particular genes involved in homology-directed repair, define a subgroup of men with prostate cancer with a more unfavorable prognosis but a therapeutic vulnerability to PARP inhibition. In current practice, mutational testing of prostate cancer patients is commonly done late i.e., when the tumor is castration resistant. In addition, most sequencing panels do not include TP53, one of the most crucial tumor suppressor genes in human cancer. In this proof-of-concept study, we sought to extend the clinical use of these molecular markers by exploring the early prognostic impact of mutations in TP53 and DNA damage repair genes in men with primary, nonmetastatic prostate cancer undergoing radical prostatectomy (RPX).

METHODS

Tumor specimens from a cohort of 68 RPX patients with intermediate (n = 11, 16.2%) or high-risk (n = 57, 83.8%) disease were analyzed by targeted next generation sequencing using a 37 DNA damage repair and checkpoint gene panel including TP53. Sequencing results were correlated to clinicopathologic variables as well as PSA persistence or time to PSA failure. In addition, the distribution of TP53 and DNA damage repair gene mutations was analyzed in three large publicly available datasets (TCGA, MSKCC and SU2C).

RESULTS

Of 68 primary prostate cancers analyzed, 23 (33.8%) were found to harbor a mutation in either TP53 (n = 12, 17.6%) or a DNA damage repair gene (n = 11, 16.2%). The vast majority of these mutations (22 of 23, 95.7%) were detected in primary tumors from patients with high-risk features. These mutations were mutually exclusive in our cohort and additional data mining suggests an enrichment of DNA damage repair gene mutations in TP53 wild-type tumors. Mutations in either TP53 or a DNA damage repair gene were associated with a significantly worse prognosis after RPX. Importantly, the presence of TP53/DNA damage repair gene mutations was an independent risk factor for PSA failure or PSA persistence in multivariate Cox regression models.

CONCLUSION

TP53 or DNA damage repair gene mutations are frequently detected in primary prostate cancer with high-risk features and define a subgroup of patients with an increased risk for PSA failure or persistence after RPX. The significant adverse impact of these alterations on patient prognosis may be exploited to identify men with prostate cancer who may benefit from a more intensified treatment.

PARP inhibition in prostate cancer

Defects in DNA damage repair genes are more common in prostate cancer than previously thought. These alterations provide an opportunity for precision oncology approaches and a number of studies have now shown that PARP inhibitors can have significant antitumor activity in men with DNA damage repair-deficient metastatic castration-resistant prostate cancer. This review summarizes the key clinical trials related to the use of PARP inhibitors in prostate cancer. Besides clinical outcomes, toxicity, and PARP inhibitor resistance, the role of different DNA repair genes in the response to PARP inhibition will be discussed.

High prevalence of DNA damage repair gene defects and TP53 alterations in men with treatment-naïve metastatic prostate cancer -Results from a prospective pilot study using a 37 gene panel

BACKGROUND

Defects in DNA damage repair genes characterize a subset of men with prostate cancer and provide an attractive opportunity for precision oncology approaches. The prevalence of such perturbations in newly diagnosed, treatment-naïve patients with a high risk for lethal disease outcome, however, has not been sufficiently explored.

PATIENTS AND METHODS

Prostate cancer specimens from 67 men with newly diagnosed early onset, localized high-risk/locally advanced or metastatic prostate cancer were included in this prospective pilot study. Tumor samples, including 30 prostate biopsies, were analyzed by targeted next generation sequencing using a formalin-fixed, paraffin-embedded tissue-optimized 37 DNA damage repair and checkpoint gene panel.

RESULTS

The drop-out rate due to an insufficient quantity of DNA was 4.5% (3 of 67 patients). In the remaining 64 patients, the rate of pathogenic DNA damage repair gene mutations was 26.6%. The highest rate of pathogenic DNA damage repair and checkpoint gene mutations was found in men with treatment-naïve metastatic prostate cancer (38.9%). In addition, a high number of likely pathogenic mutations and gene deletions were detected. Altogether, one or more pathogenic mutation, likely pathogenic mutation or gene deletion affected 43 of 64 patients (67.2%) including 29 of 36 patients (80.6%) with treatment-naïve metastatic prostate cancer. Men with metastatic prostate cancer showed a high prevalence of alterations in TP53 (36.1%).

CONCLUSIONS

This pilot study demonstrates the feasibility, performance and clinical relevance of somatic targeted next generation sequencing using a unique 37 DNA damage repair and checkpoint gene panel under routine conditions. Our results indicate that this approach can detect actionable DNA repair gene alterations, uncommon mutations as well as mutations associated with therapy resistance in a high number of patients, in particular patients with treatment-naïve metastatic prostate cancer.

Prognostic and therapeutic significance of circulating tumor cells in patients with lung cancer

BACKGROUND

Lung cancer is the second most common cancer and the main cause of cancer-related mortality worldwide. In spite of various efforts that have been made to facilitate the early diagnosis of lung cancer, most patients are diagnosed when the disease is already in stage IV, which is generally associated with the occurrence of distant metastases and a poor survival. Moreover, a large proportion of these patients will relapse after treatment, heralding the need for the stratification of lung cancer patients in addition to identifying those who are at a higher risk of relapse and, thus, require alternative and/or additional therapies. Recently, circulating tumor cells (CTCs) have been considered as valuable markers for the early diagnosis, prognosis and risk stratification of cancer patients, and they have been found to be able to predict the survival of patients with various types of cancer, including lung cancer. Additionally, the characterization of CTCs has recently provided fascinating insights into the heterogeneity of tumors, which may be instrumental for the development of novel targeted therapies.

CONCLUSIONS

Here we review our current understanding of the significance of CTCs in lung cancer metastasis. We also discuss prominent studies reporting the utility of enumeration and characterization of CTCs in lung cancer patients as prognostic and pharmacodynamic biomarkers for those who are at a higher risk of metastasis and drug resistance.

Low Numbers of Vascular Vessels Correlate to Progression in Hormone-Naïve Prostate Carcinomas Undergoing Radical Prostatectomy

Vascularization influences tumor development by supporting the nutrition and dissemination of tumor cells. On the other hand, a low number of vascular vessels (VV^low) may induce hypoxia, accounting for selection of resistant clone(s) of tumor cells. This study aimed to evaluate the prognostic significance of vascular (VV) and lymphatic vessels (LV) in prostate cancer (PCa). Tumor samples from 400 PCa patients undergoing radical prostatectomy (RP) were prepared in duplex as tissue microarrays. Numbers of VV and LV were evaluated using immunohistochemistry detecting CD34 and podoplanin, respectively, and correlated to clinical data, biochemical recurrence (BR), and proteins analyzed in tumor cells. VV^low and LV were found in 32% and 43% of patients with informative PCa samples, respectively. VV^low correlated with a shorter time to BR 3, 5, and 10 years after RP in hormone-naïve patients (p = 0.028, p = 0.027 and p = 0.056, respectively). It was also shown to be an independent prognostic factor 5 years after surgery (multivariate analysis, p = 0.046). Tumors characterized by VV^low expressed the epithelial cell adhesion molecule, EpCAM, less frequently (p = 0.016) and revealed a borderline correlation to increased levels of tumor cell invasion marker Loxl-2 (p = 0.059). No correlations were found for LV. In summary, VV^low in hormone-naïve patients undergoing RP has prognostic potential and seems to be related to an aggressive phenotype of tumor cells.

Heterogeneity in Circulating Tumor Cells: The Relevance of the Stem-Cell Subset

The release of circulating tumor cells (CTCs) into vasculature is an early event in the metastatic process. The analysis of CTCs in patients has recently received widespread attention because of its clinical implications, particularly for precision medicine. Accumulated evidence documents a large heterogeneity in CTCs across patients. Currently, the most accepted view is that tumor cells with an intermediate phenotype between epithelial and mesenchymal have the highest plasticity. Indeed, the existence of a meta-stable or partial epithelial–mesenchymal transition (EMT) cell state, with both epithelial and mesenchymal features, can be easily reconciled with the concept of a highly plastic stem-like state. A close connection between EMT and cancer stem cells (CSC) traits, with enhanced metastatic competence and drug resistance, has also been described. Accordingly, a subset of CTCs consisting of CSC, present a stemness profile, are able to survive chemotherapy, and generate metastases after xenotransplantation in immunodeficient mice. In the present review, we discuss the current evidence connecting CTCs, EMT, and stemness. An improved understanding of the CTC/EMT/CSC connections may uncover novel therapeutic targets, irrespective of the tumor type, since most cancers seem to harbor a pool of CSCs, and disclose important mechanisms underlying tumorigenicity.

ALDH1-positive intratumoral stromal cells indicate differentiated epithelial-like phenotype and good prognosis in prostate cancer

Aldehyde dehydrogenase 1 (ALDH1) characterizes tumor-initiating cells in solid tumors; however, little is known about its expression in intratumoral stromal cells. Herein, we aimed to dissect its potential dual relevance in prostate cancer (PCa). ALDH1 expression was evaluated immunohistochemically in tumor and stromal cells in primary PCa and metastases. It was correlated to clinico-pathologic parameters, patients' outcome, and selected proteins (CK5/6, CK14, CK8/18, CK19, EpCAM, Ki-67, E-cadherin, N-cadherin, and vimentin). ALDH1 protein was detected in tumor and stromal cells in 16% and 67% of 348 primary PCa, respectively. Tumor cell ALDH1 expression was associated with advanced T stage (P = 0.009), higher Gleason score (P = 0.016), shorter time to biochemical recurrence (TBR P = 0.010) and CK14 expression (P = 0.023). Stromal cell ALDH1 expression correlated to lower T stage (P = 0.008) and Gleason score (P = 0.016), N0 stage (P = 0.017), and longer TBR (P = 0.017). It occurred to be an independent predictor of good prognosis in the subgroup of d'Amico high-risk patients (multivariate analysis, P = 0.050). ALDH1-positive stromal cells were found in tumors characterized frequently by CK8/18 (P = 0.033) or EpCAM expression (P < 0.001) and rarely by epithelial-mesenchymal transition defined as CK8/18(-)vimentin(+) phenotype (P = 0.003). ALDH1-positive tumor and stromal cells were detected in 33% and 41% of hormone naive lymph node metastases (n = 63), 52% and 24% of castration resistant bone metastases, as well as 89% and 28% of castration resistant visceral metastases (n = 21), respectively. We have determined that contrary to tumor cell ALDH1, the presence of stromal ALDH1 is associated with epithelial phenotype of primary PCa, improved clinical outcome, and is less frequent in PCa metastases.

Somatic aberrations of BRCA1 gene are associated with ALDH1, EGFR, and tumor progression in prostate cancer

BRCA1 is a pivotal tumor suppressor. Its dysfunction is known to play a role in different tumors. Among others, BRCA1 germline mutations account for higher risk and more aggressive course of prostate cancer (PCa). In addition, somatic BRCA1 gene loss was demonstrated to be a signature of PCa dissemination to lymph nodes and peripheral blood, and indicate worse clinical outcome. In order to substantiate the data for BRCA1 gene loss in PCa and reveal its phenotypical background, BRCA1 gene status was assessed in a large cohort of PCa patients and compared to different molecular factors. BRCA1 gene dosage was assessed in 2398 tumor samples from 1,199 PCa patients using fluorescent in situ hybridization. It was compared to clinico-pathological parameters, patients' outcome as well as selected proteins (Ki-67, apoptosis marker, cytokeratins, vimentin, E- and N-cadherin, ALDH1 and EGFR) examined immunohistochemically. BRCA1 losses were found in 10%, whereas gains appeared in 7% of 603 informative PCa patients. BRCA1 losses correlated to higher T stage (p = 0.027), Gleason score (p = 0.039), shorter time to biochemical recurrence in patients with Gleason score > 7 independently of other factors (multivariate analysis, p = 0.005) as well as expression of proteins regulating stemness and epithelial-mesenchymal transition, that is, ALDH1 (p = 0.021) and EGFR (p = 0.011), respectively. BRCA1 gains correlated to shorter time to metastasis (p = 0.012) and expression of ALDH1 (p = 0.014). These results support the assumption that BRCA1 gene losses contribute to a progressive and stem cell-like phenotype of PCa. Furthermore, they reveal that also BRCA1 gain conceivably representing loss-of-function might mark more invasive tumors.

Circulating tumor cells: potential markers of minimal residual disease in ovarian cancer? a study of the OVCAD consortium

Purpose

In 75% of ovarian cancer patients the tumor mass is completely eradicated by established surgical and cytotoxic treatment; however, the majority of the tumors recur within 24 months. Here we investigated the role of circulating tumor cells (CTCs) indicating occult tumor load, which remains inaccessible by established diagnostics.

Experimental design

Blood was taken at diagnosis (baseline samples, n = 102) and six months after completion of adjuvant first-line chemotherapy (follow-up samples; n = 78). CTCs were enriched by density gradient centrifugation. A multi-marker immunostaining was established and further complemented by FISH on CTCs and tumor/metastasis tissues using probes for stem-cell like fusion genes MECOM and HHLA1.

Results

CTCs were observed in 26.5% baseline and 7.7% follow-up blood samples at a mean number of 12.4 and 2.8 CTCs per ml blood, respectively. Baseline CTCs indicated a higher risk of death in R0 patients with complete gross resection (univariate: HR 2.158, 95% CI 1.111–4.191, p = 0.023; multivariate: HR 2.720, 95% CI 1.340–5.522, p = 0.006). At follow-up, the presence of CTCs was associated with response to primary treatment as assessed using RECIST criteria. Chromosomal gains at MECOM and HHLA1 loci suggest that the observed cells were cancer cells and reflect pathophysiological decisive chromosomal aberrations of the primary and metastatic tumors.

Conclusions

Our data suggest that CTCs detected by the multi-marker protein panel and/or MECOM/HHLA1 FISH represent minimal residual disease in optimally debulked ovarian cancer patients. The role of CTCs cells especially for clinical therapy stratification of the patients has to be validated in consecutive larger studies applying standardized treatment schemes.

Evaluation and consequences of heterogeneity in the circulating tumor cell compartment

A growing understanding of the molecular biology of cancer and the identification of specific aberrations driving cancer evolution have led to the development of various targeted agents. Therapeutic decisions concerning these drugs are often guided by single biopsies of the primary tumor. Yet, it is well known that tumors can exhibit significant heterogeneity and change over time as a result of selective pressure. Circulating tumor cells (CTCs) are shed from various tumor sites and are thought to represent the molecular landscape of a patient's overall tumor burden. Moreover, a minimal-invasive liquid biopsy facilitates monitoring of clonal evolution during therapy pressure and disease progression in real-time. While more information becomes available regarding heterogeneity among CTCs, comparison between these studies is needed. In this review, we focus on the genomic and transcriptional heterogeneity found in the CTC compartment, and its significance for clinical decision making.

Minimal residual disease in breast cancer: an overview of circulating and disseminated tumour cells

Within the field of cancer research, focus on the study of minimal residual disease (MRD) in the context of carcinoma has grown exponentially over the past several years. MRD encompasses circulating tumour cells (CTCs)—cancer cells on the move via the circulatory or lymphatic system, disseminated tumour cells (DTCs)—cancer cells which have escaped into a distant site (most studies have focused on bone marrow), and resistant cancer cells surviving therapy—be they local or distant, all of which may ultimately give rise to local relapse or overt metastasis. Initial studies simply recorded the presence and number of CTCs and DTCs; however recent advances are allowing assessment of the relationship between their persistence, patient prognosis and the biological properties of MRD, leading to a better understanding of the metastatic process. Technological developments for the isolation and analysis of circulating and disseminated tumour cells continue to emerge, creating new opportunities to monitor disease progression and perhaps alter disease outcome. This review outlines our knowledge to date on both measurement and categorisation of MRD in the form of CTCs and DTCs with respect to how this relates to cancer outcomes, and the hurdles and future of research into both CTCs and DTCs.

The Role of CTCs as Tumor Biomarkers

Detection of Circulating Tumor Cells (CTCs) in peripheral blood can serve as a "liquid biopsy" approach and as a source of valuable tumor markers. CTCs are rare, and thus their detection, enumeration and molecular characterization are very challenging. CTCs have the unique characteristic to be non-invasively isolated from blood and used to follow patients over time, since these cells can provide significant information for better understanding tumour biology and tumour cell dissemination. CTCs molecular characterization offers the unique potential to understand better the biology of metastasis and resistance to established therapies and their analysis presents nowadays a promising field for both advanced and early stage patients. In this chapter we focus on the latest findings concerning the clinical relevance of CTC detection and enumeration, and discuss their potential as tumor biomarkers in various types of solid cancers. We also highlight the importance of performing comparison studies between these different methodologies and external quality control systems for establishing CTCs as tumor biomarkers in the routine clinical setting.

Circulating tumor cell technologies†

Circulating tumor cells, a component of the “liquid biopsy”, hold great potential to transform the current landscape of cancer therapy. A key challenge to unlocking the clinical utility of CTCs lies in the ability to detect and isolate these rare cells using methods amenable to downstream characterization and other applications. In this review, we will provide an overview of current technologies used to detect and capture CTCs with brief insights into the workings of individual technologies. We focus on the strategies employed by different platforms and discuss the advantages of each. As our understanding of CTC biology matures, CTC technologies will need to evolve, and we discuss some of the present challenges facing the field in light of recent data encompassing epithelial‐to‐mesenchymal transition, tumor‐initiating cells, and CTC clusters.

We present a comprehensive overview of CTC detection and capture technologies.

We provide a conceptual description of strategies used in different technologies.

We highlight the key features of individual technologies.

We discuss CTC technology performance in the context of clinical studies.

Nanoelectromechanical Chip (NELMEC) Combination of Nanoelectronics and Microfluidics to Diagnose Epithelial and Mesenchymal Circulating Tumor Cells from Leukocytes

An integrated nano-electromechanical chip (NELMEC) has been developed for the label-free distinguishing of both epithelial and mesenchymal circulating tumor cells (ECTCs and MCTCs, respectively) from white blood cells (WBCs). This nanoelectronic microfluidic chip fabricated by silicon micromachining can trap large single cells (>12 µm) at the opening of the analysis microchannel arrays. The nature of the captured cells is detected using silicon nanograss (SiNG) electrodes patterned at the entrance of the channels. There is an observable difference between the membrane capacitance of the ECTCs and MCTCs and that of WBCs (measured using SiNG electrodes), which is the key indication for our diagnosis. The NELMEC chip not only solves the problem of the size overlap between CTCs and WBCs but also detects MCTCs without the need for any markers or tagging processes, which has been an important problem in previously reported CTC detection systems. The great conductivity of the gold-coated SiNG nanocontacts as well as their safe penetration into the membrane of captured cells, facilitate a precise and direct signal extraction to distinguish the type of captured cell. The results achieved from epithelial (MCF-7) and mesenchymal (MDA-MB231) breast cancer cells circulated in unprocessed blood suggest the significant applications for these diagnostic abilities of NELMEC.

Interaction between circulating cancer cells and platelets: clinical implication

Metastasis is the main cause of cancer-associated mortality. During this complicated process, some cancer cells, also called circulating tumor cells (CTCs), detach from primary sites, enter bloodstream and extravasate at metastatic site. Thrombocytosis is frequently observed in patients with metastatic cancers suggesting the important role of platelets in metastasis. Therefore this review focuses on how platelets facilitate the generation of CTCs, protect them from various host attacks, such as immune assaults, apoptosis and shear stress, and regulate CTCs intravasation/extravasation. Platelet-derived cytokines and receptors are involved in this cascade. Identification the mechanisms underlie platelet-CTCs interactions could lead to the development of new platelet-targeted therapeutic strategy to reduce metastasis.

The role of Rak in the regulation of stability and function of BRCA1

BRCA1 is an important player in the DNA damage response signaling, and its deficiency results in genomic instability. A complete loss or significantly reduced BRCA1 protein expression is often found in sporadic breast cancer cases despite the absence of genetic or epigenetic aberrations, suggesting the existence of other regulatory mechanisms controlling BRCA1 protein expression. Herein, we demonstrate that Fyn-related kinase (Frk)/Rak plays an important role in maintaining genomic stability, possibly in part through positively regulating BRCA1 protein stability and function via tyrosine phosphorylation on BRCA1 Tyr1552. In addition, Rak deficiency confers cellular sensitivity to DNA damaging agents and poly(ADP-ribose) polymerase (PARP) inhibitors. Overall, our findings highlight a critical role of Rak in the maintenance of genomic stability, at least in part, through protecting BRCA1 and provide novel treatment strategies for patients with breast tumors lacking Rak.

Challenges in circulating tumour cell research

During the past ten years, circulating tumour cells (CTCs) have received enormous attention as new biomarkers and the subject of basic research. Although CTCs are already used in numerous clinical trials, their clinical utility is still under investigation. Many issues regarding the detection and characterization of CTCs remain unknown. In this Opinion article, we propose a conceptual framework of CTC assays and point out current challenges of CTC research, which might structure this dynamic field of translational cancer research.

[Circulating tumor cells: cornerstone of personalized medicine]

Cancer treatment has evolved toward personalized medicine. It is mandatory for clinicians to ascertain tumor biological features in order to optimize patients' treatment. Identification and characterization of circulating tumor cells demonstrated a prognostic value in many solid tumors. Here, we describe the main technologies for identification and characterization of circulating tumor cells and their clinical application in gynecologic and breast cancers.

The biological and clinical importance of epithelial-mesenchymal transition in circulating tumor cells

Movement of tumor cells from a primary tumor to a nonadjacent or distant site is a contiguous and complex process. Among the multiple natural cellular programs that promote initiation and progression of tumor metastasis, epithelial-mesenchymal transition (EMT) may play a key role in the ultimate generation of a metastatic foci. Acquisition of the EMT phenotype by tumor cells not only increases their migration and invasion potentials, thereby facilitating their ability to infiltrate blood vessels and to produce circulating tumor cells (CTCs), but also promotes survival of CTCs in the bloodstream and their ability to extravasate out of the circulatory system and invade proximal tissues. In organs distal to the primary tumor, the phenotypic switching mechanism of mesenchymal-epithelial transition (MET) enables CTCs to grow and colonize, enhancing the likelihood of establishing metastasis. In addition, CTCs that have undergone EMT attain increased resistance to chemotherapy and targeted therapy. CTCs with the EMT phenotype have become recognized as an active source of metastases, and targeting EMT/MET processes during the individual steps of tumor metastasis represents a promising new approach for alleviating cancer metastasis and recurrence. In this article, we focus on the biological and clinical importance of EMT and/or MET in CTCs during the individual steps of tumor metastasis, summarizing the recent findings of the regulatory roles played by EMT and/or MET in the generation, survival, and recolonization of CTCs and discussing the EMT-targeting strategies developed for tumor diagnosis as well as their potential for management of metastatic malignant diseases.

Clinical value of extended pelvic lymph node dissection in patients subjected to radical prostatectomy

Introduction

Extended pelvic lymph node dissection (ePLND) is advised to complement radical prostatectomy (RP) in intermediate and high risk prostate cancer patients.

Aim

To assess the risk of nodal involvement in patients subjected to laparoscopic radical prostatectomy and to characterize the group of patients with lymph node (LN) metastases.

Material and methods

Data of patients subjected to laparoscopic radical prostatectomy with ePLND between February 2011 and June 2013 were analyzed. The LN that were removed included presacral nodes, common, external and internal iliac nodes and obturator ones.

Results

Mean number of removed LNs was 19. Metastases within LN were found in 13 (16.6%) patients. In comparison to those without LN involvement, patients who were found to have LN metastases had a greater number of positive biopsy cores (3.7 vs. 5.3, p < 0.01), maximum percentage of cancer in biopsy core (47.0 vs. 67.6, p < 0.01), greater biopsy and specimen Gleason scores (7.0 vs. 7.7 and 7.0 vs. 7.8) and more frequently advanced clinical and pathological stage. The most frequent landing sites of prostate cancer were obturator and presacral nodes (100% and 38%). Eleven patients (85%) among those with positive LN had locally advanced disease.

Conclusions

The risk of LN metastases in intermediate and high risk prostate cancer patients is significant. Therefore, if radical prostatectomy is chosen, ePLND should be performed. The majority of patients with involvement of pelvic LN have locally advanced disease which would refer them to adjuvant radiation if managed without nodal dissection.

Circulating tumor cells as promising novel biomarkers in solid cancers

The presence of circulating tumor cells (CTCs) in peripheral blood can serve as a "liquid biopsy" approach and has thus emerged lately as one of the hottest fields in cancer research. CTCs can be isolated from blood in a non-invasive approach, and can be used to follow patients over time since these cells can provide significant information for a better understanding of tumor biology and tumor cell dissemination. CTC molecular characterization offers the unique potential to better understand the biology of metastasis and resistance to established therapies, and analysis of these cells presents a promising field for both advanced and early-stage patients. CTC detection, enumeration, and molecular characterization are very challenging since CTCs are rare, and the amount of available sample is very limited. Since detection of CTCs has been shown to be of considerable utility in the clinical management of patients with solid cancers, various analytical systems for their isolation and detection have been developed. New areas of research are directed towards developing novel assays for single-CTC isolation and molecular characterization. The clinical significance of CTCs has been evaluated in many types of solid cancers, and the CTC enumeration test in metastatic breast, colorectal, and prostate cancer was cleared by the FDA almost a decade ago. This review is mainly focused on the clinical potential of CTCs as novel biomarkers in 10 different types of solid cancers: breast, ovarian, prostate, lung, colorectal, hepatocellular carcinoma, pancreatic, head and neck, bladder cancer and melanoma.

Aspirin inhibit platelet-induced epithelial-to-mesenchymal transition of circulating tumor cells (Review)

Metastasis, a cascade of events beginning with epithelial-to-mesenchymal transition (EMT), is the main cause of cancer-related mortality. EMT endows circulating cancer cells (CTCs) with invasive and anti-apoptotic properties. These transitioning cells leave the primary tumor site and travel through the circulation to populate remote organs, even prior to the onset of clinical symptoms. During this journey, CTCs activate platelets, which in turn secrete α-granules. These α-granules contain high levels of transforming growth factor-β (TGF-β) and platelet-derived growth factor (PDGF), both considered to be powerful activators of EMT. Recently, regular aspirin use was associated with a reduced risk of cancer metastasis. However, the molecular mechanism underlying the chemotherapeutic effects of aspirin on metastasis has not been fully elucidated. As platelets lack a nucleus, regular aspirin use may exert long-lasting effects on irreversible inhibition of cyclooxygenase (COX)-1 and, subsequently, the secretion of α-granules, which contributes to the maintenance of the EMT state of CTCs. Thus, we hypothesized that the inhibition of platelet-induced EMT of CTCs through the COX-1 signaling pathway may contribute to the intriguing antimetastatic potential of aspirin.

New frontiers in circulating tumor cell analysis: A reference guide for biomolecular profiling toward translational clinical use

Circulating tumor cells (CTCs) are now routinely isolated from blood, and measurement of CTC concentrations appears to correlate well with survival in patients with cancer. Interrogation of the molecular profile of CTCs for expression of protein biomarkers, genetic variants and gene expression provides opportunities to use this information to guide personalized treatment, monitor therapy and detect emerging resistance. However, successful application of profiling techniques requires analyses that deliver a reliable and clinically relevant representation of a patient's cancer as it changes with time. Here, we comprehensively review the current knowledge of therapeutically relevant biomarkers in isolated CTCs obtained by fluorescence imaging and genomic profiling approaches. The reviewed data support the notion that molecular profiling of CTCs will provide a reliable representation or surrogate index of tumor burden. Large-scale translational trials, many currently in progress, will provide critical data to progress CTC analysis toward wider clinical use in personalized treatment.

Real-time liquid biopsy in cancer patients: fact or fiction?

Distant metastases harbor unique genomic characteristics not detectable in the corresponding primary tumor of the same patient and metastases located at different sites show a considerable intrapatient heterogeneity. Thus, the mere analysis of the resected primary tumor alone (current standard practice in oncology) or, if possible, even reevaluation of tumor characteristics based on the biopsy of the most accessible metastasis may not reveal sufficient information for treatment decisions. Here, we propose that this dilemma can be solved by a new diagnostic concept: liquid biopsy, that is, analysis of therapeutic targets and drug resistance-conferring gene mutations on circulating tumor cells (CTC) and cell-free circulating tumor DNA (ctDNA) released into the peripheral blood from metastatic deposits. We discuss the current challenges and future perspectives of CTCs and ctDNA as biomarkers in clinical oncology. Both CTCs and ctDNA are interesting complementary technologies that can be used in parallel in future trials assessing new drugs or drug combinations. We postulate that the liquid biopsy concept will contribute to a better understanding and clinical management of drug resistance in patients with cancer.

Plasticity of disseminating cancer cells in patients with epithelial malignancies

Current models suggest that at a certain but yet undefined time point of tumour development malignant cells with an aggressive phenotype start to disseminate via the blood stream into distant organs. This invasive phenotype appears to be associated with an epithelial-mesenchymal transition (EMT), which enables detachment of tumour cells from a primary site and migration. The reverse process of mesenchymal-epithelial transition (MET) might play a crucial role in the further steps of metastasis when circulating tumour cells (CTCs) settle down in distant organs and establish (micro-)metastasis. Nevertheless, the exact mechanisms and interplay of EMT and MET are only partially understood and their relevance in cancer patients is unclear. Research groups have just started to apply EMT-related markers in their studies on CTCs in cancer patients. In the present review, we summarize and discuss the current state of investigations on CTCs in the context of research on EMT/MET.

Tumor cell dissemination: emerging biological insights from animal models and cancer patients

Circulating tumor cells (CTCs) and disseminated tumor cells (DTCs) are increasingly recognized for their potential utility in disease monitoring and therapeutic targeting. The clinical application of CTC/DTC requires better understanding of the biological mechanisms behind tumor dissemination, the survival of DTCs, and their activation to aggressive growth from dormancy. Recent research using animal models of DTCs and CTCs have provided novel insights into these processes. Here, we discuss these findings in the context of results obtained from the clinical analyses of CTCs and DTCs, which demonstrate that the animal models mimic, in many aspects, the complex situation in patients.

Circulating tumor cells as therapy-related biomarkers in cancer patients

Carcinomas (tumors of epithelial origin) are responsible for most of all new cancers in the industrialized countries. Due to the high mortality rate caused by the metastatic spread of aggressive cancer cells, there is an urgent demand in finding new biomarkers, which should detect early formation of metastases and monitor efficacy of systemic adjuvant therapy in a timely manner. It has been considered that the molecular analysis of cells which are shed from tumors into the blood system (circulating tumor cells (CTCs)) might provide new insights for the clinical management of cancer, probably far earlier than using traditional high-resolution imaging technologies. Clinical trials indicated that CTCs can be deployed for diagnostic, monitoring, and prognostic purposes. Furthermore, these cells are discussed to be suitable as predictive markers. In any case, identification of CTCs requires innovative and challenging technologies as detection methods should be specific, sensitive, standardized, and highly reproducible. Although many different approaches have been developed until now, only the CellSearch™ method has been cleared by the American Food and Drug Administration. Although the detection of CTCs has already shown to have a prognostic impact in many tumor entities including breast, prostate, lung and colon cancer, ongoing and future studies are aimed to explore whether CTCs can be used for an individual therapy decision making including novel immunotherapeutic approaches. This review discusses (1) different detection strategies for CTCs, (2) their clinical impact, and (3) the potential use of CTCs guiding the treatment of individual cancer patients.

PTEN losses exhibit heterogeneity in multifocal prostatic adenocarcinoma and are associated with higher Gleason grade

Prostatic adenocarcinoma is an epithelial malignancy characterized by marked histological heterogeneity. It most often has a multifocal distribution within the gland, and different Gleason grades may be present within different foci. Data from our group and others have shown that the genomic deletion of the phosphatase and tensin homolog deleted on chromosome 10 (PTEN) tumor suppressor gene and the disruption of the ETS gene family have a central role in prostate cancer and are likely to be associated with Gleason grade. In this study, prostate cancer samples were systematically analyzed to determine whether there was concordance between PTEN losses and TMPRSS2-ERG fusion rearrangements, within or between foci in multifocal disease, using well-annotated tissue microarrays (TMAs) consisting of 724 cores derived from 142 radical prostatectomy specimens. Three-color fluorescence in situ hybridization analysis of both the PTEN deletion and the TMPRSS2-ERG fusion was used to precisely map genetic heterogeneity, both within and between tumor foci represented on the TMA. PTEN deletion was observed in 56 of 134 (42%) patients (hemizygous=42 and homozygous=14). TMPRSS2-ERG fusion was observed in 63 of 139 (45%) patients. When analyzed by Gleason pattern for a given TMA core, PTEN deletions were significantly associated with Gleason grades 4 or 5 over grade 3 (P<0.001). Although TMPRSS2-ERG fusions showed a strong relationship with PTEN deletions (P=0.007), TMPRSS2-ERG fusions did not show correlation with Gleason grade. The pattern of genetic heterogeneity of PTEN deletion was more diverse than that observed for TMPRSS2-ERG fusions in multifocal disease. However, the marked interfocal discordance for both TMPRSS2-ERG fusions and PTEN deletions was consistent with the concept that multiple foci of prostate cancer arise independently within the same prostate, and that individual tumor foci can have distinct patterns of genetic rearrangements.

Circulating Tumor Cells: Liquid Biopsy of Cancer

BACKGROUND

The detection and molecular characterization of circulating tumor cells (CTCs) are one of the most active areas of translational cancer research, with &gt;400 clinical studies having included CTCs as a biomarker. The aims of research on CTCs include (a) estimation of the risk for metastatic relapse or metastatic progression (prognostic information), (b) stratification and real-time monitoring of therapies, (c) identification of therapeutic targets and resistance mechanisms, and (d) understanding metastasis development in cancer patients.

CONTENT

This review focuses on the technologies used for the enrichment and detection of CTCs. We outline and discuss the current technologies that are based on exploiting the physical and biological properties of CTCs. A number of innovative technologies to improve methods for CTC detection have recently been developed, including CTC microchips, filtration devices, quantitative reverse-transcription PCR assays, and automated microscopy systems. Molecular-characterization studies have indicated, however, that CTCs are very heterogeneous, a finding that underscores the need for multiplex approaches to capture all of the relevant CTC subsets. We therefore emphasize the current challenges of increasing the yield and detection of CTCs that have undergone an epithelial–mesenchymal transition. Increasing assay analytical sensitivity may lead, however, to a decrease in analytical specificity (e.g., through the detection of circulating normal epithelial cells).

SUMMARY

A considerable number of promising CTC-detection techniques have been developed in recent years. The analytical specificity and clinical utility of these methods must be demonstrated in large prospective multicenter studies to reach the high level of evidence required for their introduction into clinical practice.

PARP inhibitors: mechanism of action and their potential role in the prevention and treatment of cancer

The use of poly(ADP-ribose) polymerase (PARP) inhibitors provided proof-of-concept for a synthetic lethal anti-cancer strategy as a result of their efficacy and favourable toxicity profile in BRCA1/2 mutation carriers. Efforts are underway to identify a broader group of patients with genomic susceptibility that may benefit from these agents. In an endeavour to enhance anti-tumour effects, PARP inhibitors have been combined with traditional cytotoxic therapy and radiotherapy; however, optimization of dosing schedules for these combination regimens remains key to maximizing benefit whilst mitigating the potential for increased toxicity. With ongoing clinical experience of PARP inhibition, mechanisms of resistance to these therapies are being elucidated and specific challenges to long-term administration of these drugs will need to be addressed. Development of robust predictive biomarkers of response for optimal patient selection and rational combination strategies must be pursued if the full potential of these agents is to be realized.

Bioinformatics tools allow targeted selection of chromosome enumeration probes and aneuploidy detection

Accurate determination of cellular chromosome complements is a highly relevant issue beyond prenatal/pre-implantation genetic analyses or stem cell research, because aneusomy may be an important mechanism by which organisms control the rate of fetal cellular proliferation and the fate of regenerating tissues. Typically, small amounts of individual cells or nuclei are assayed by in situ hybridization using chromosome-specific DNA probes. Careful probe selection is fundamental to successful hybridization experiments. Numerous DNA probes for chromosome enumeration studies are commercially available, but their use in multiplexed hybridization assays is hampered due to differing probe-specific hybridization conditions or a lack of a sufficiently large number of different reporter molecules. Progress in the International Human Genome Project has equipped the scientific community with a wealth of unique resources, among them recombinant DNA libraries, physical maps, and data-mining tools. Here, we demonstrate how bioinformatics tools can become an integral part of simple, yet powerful approaches to devise diagnostic strategies for detection of aneuploidy in interphase cells. Our strategy involving initial in silico optimization steps offers remarkable savings in time and costs during probe generation, while at the same time significantly increasing the assay’s specificity, sensitivity, and reproducibility.

Identifying and exploiting defects in the Fanconi anemia/BRCA pathway in oncology

Defects in components of DNA repair pathways are responsible for numerous hereditary cancer syndromes and are also common in many sporadic malignancies. Inherited mutations in the breast cancer susceptibility genes BRCA1 and BRCA2 or components of the Fanconi anemia (FA) complex incite genomic instability and predispose to malignancy. The products of the BRCA and FA genes participate in a conserved DNA damage repair pathway that is responsible for repairing interstrand crosslinks and double-strand DNA breaks by homologous recombination. While the genetic instability resulting from FA/BRCA dysfunction contributes to cancer pathogenesis, deficiency of these genes also lends to therapeutic exploitation. Crosslinking agents and ionizing radiation induce damage in cancer cells that requires the FA/BRCA pathway to be resolved; thus cancers that are deficient in BRCA1, BRCA2, or any other component of the FA/BRCA pathway are hypersensitive to these agents. Moreover, emerging synthetic lethal strategies offer opportunities to selectively target cancer cells with defects in homologous recombination. Conversely, enhanced activity of the FA/BRCA pathway is responsible for acquired resistance to specific therapeutic agents, suggesting that both dysfunction and hyperfunction of the FA/BRCA repair machinery are rational targets for cancer therapy. Selection of specific cytotoxic agents based on repair capacity may improve responses and enable personalized cytotoxic chemotherapy. This article reviews the FA/BRCA pathway and current approaches to identify deficiencies within it, discusses synthetic lethality and enhanced repair capacity as causes of therapeutic hypersensitivity and resistance, respectively, and highlights recent studies that have linked FA/BRCA pathway function with therapeutic efficacy.

Considerations in the development of circulating tumor cell technology for clinical use

This manuscript summarizes current thinking on the value and promise of evolving circulating tumor cell (CTC) technologies for cancer patient diagnosis, prognosis, and response to therapy, as well as accelerating oncologic drug development. Moving forward requires the application of the classic steps in biomarker development–analytical and clinical validation and clinical qualification for specific contexts of use. To that end, this review describes methods for interactive comparisons of proprietary new technologies, clinical trial designs, a clinical validation qualification strategy, and an approach for effectively carrying out this work through a public-private partnership that includes test developers, drug developers, clinical trialists, the US Food & Drug Administration (FDA) and the US National Cancer Institute (NCI).

The connectivity of lymphogenous and hematogenous tumor cell dissemination: biological insights and clinical implications

Although tumor cells are found in the blood early after tumorigenesis, dissemination through the lymphatic system and in particular the formation of lymph node metastases has long been considered to be a driving force behind the formation of secondary tumors in distant vital organs. Contemporary experimental observations and clinical trial results suggest that this may not be the case. In this review we survey the evidence for both points of view, and examine the hypothesis that the prognostic relevance of lymph node metastases may lie in their ability to indicate that primary tumors are producing soluble factors that have the potential to promote metastasis at these distant sites, for example by releasing tumor cells from dormancy. Furthermore, the interconnectivity between the lymphatic and blood circulatory systems underscores the relevance of the analysis of the properties of circulating and disseminated tumor cells for prognostic evaluation, patient stratification and understanding the biology of metastasis. We therefore give an overview of the current state of the art in this field.

The role of BRCA1 and BRCA2 in prostate cancer

One of the strongest risk factors for prostate cancer is a family history of the disease. Germline mutations in the breast cancer predisposition gene 2 (BRCA2) are the genetic events known to date that confer the highest risk of prostate cancer (8.6-fold in men ≤65 years). Although the role of BRCA2 and BRCA1 in prostate tumorigenesis remains unrevealed, deleterious mutations in both genes have been associated with more aggressive disease and poor clinical outcomes. The increasing incidence of prostate cancer worldwide supports the need for new methods to predict outcome and identify patients with potentially lethal forms of the disease. As we present here, BRCA germline mutations, mainly in the BRCA2 gene, are one of those predictive factors. We will also discuss the implications of these mutations in the management of prostate cancer and hypothesize on the potential for the development of strategies for sporadic cases with similar characteristics.

Prognostic value of TOP2A gene amplification and chromosome 17 polysomy in early breast cancer

The aim of this study was to analyze the occurrence of TOP2A gene amplification and chromosome 17 polysomy in patients with early breast cancer and to correlate the status of these alterations with the prognostic significance expressed as patients' clinical features and survival. Such concurrent analyses of TOP2A gene status and chromosome 17 polysomy have not been performed before. Study group included 149 consecutive stage I-III patients administered standard multimodality treatment. TOP2A abnormalities were examined by standard fluorescence in situ hybridization (FISH) and developed by our group quantitative real-time PCR (qPCR). TOP2A amplification and deletion assessed by FISH were found in 23% and 7% of the tumours, respectively, and by qPCR in 31% and 11% of the tumours, respectively. Chromosome 17 polysomy was detected in 40% of the cases. TOP2A amplification (by qPCR) correlated with shorter disease-free survival (p = 0.03) and overall survival (p = 0.047), and the prognostic value of TOP2A was confirmed in the multivariate analysis (HR = 3.22, 95% CI 1.09-9.56, p = 0.03). TOP2A gene amplification, but not chromosome 17 polysomy, carries negative prognostic information in early breast cancer. Given the aforementioned results, qPCR might serve as a prognostic tool in determining the patient's prognosis.

Prostate cancer as a model system for genetic diversity in tumors

This chapter will summarize novel understandings of the early molecular events in prostatic carcinogenesis that may underlie both the genetic and clinical heterogeneity. Areas covered include preneoplasia, stem cell concepts, telomere abnormalities, and the nature of tumor-stromal interactions. The oncogenomics of prostate cancer is reviewed with emphasis on androgen signaling, ETS gene family aberrations, and PTEN deletion. The notion that "field cancerization," coupled with genomic instability may explain both the occurrence of multifocal disease, and the recent observations of genetic diversity of ERG alteration in individual tumors are discussed. Collectively, genomic studies are rapidly moving human prostate cancer closer to the promise of personalized medicine, so that specific genetic profiles of individual tumors will determine the best therapeutic approaches.