PARP inhibitors: A new era of targeted therapy

Not All Next Generation Sequencing Diagnostics are Created Equal: Understanding the Nuances of Solid Tumor Assay Design for Somatic Mutation Detection

The molecular characterization of tumors using next generation sequencing (NGS) is an emerging diagnostic tool that is quickly becoming an integral part of clinical decision making. Cancer genomic profiling involves significant challenges including DNA quality and quantity, tumor heterogeneity, and the need to detect a wide variety of complex genetic mutations. Most available comprehensive diagnostic tests rely on primer based amplification or probe based capture methods coupled with NGS to detect hotspot mutation sites or whole regions implicated in disease. These tumor panels utilize highly customized bioinformatics pipelines to perform the difficult task of accurately calling cancer relevant alterations such as single nucleotide variations, small indels or large genomic alterations from the NGS data. In this review, we will discuss the challenges of solid tumor assay design/analysis and report a case study that highlights the need to include complementary technologies (i.e., arrays) and germline analysis in tumor testing to reliably identify copy number alterations and actionable variants.

The hallmarks of castration-resistant prostate cancers

Prostate cancer has become a real public health issue in industrialized countries, mainly due to patients' relapse by castration-refractory disease after androgen ablation. Castration-resistant prostate cancer is an incurable and highly aggressive terminal stage of prostate cancer, seriously jeopardizing the patient's quality of life and lifespan. The management of castration-resistant prostate cancer is complex and has opened new fields of research during the last decade leading to an improved understanding of the biology of the disease and the development of new therapies. Most advanced tumors resistant to therapy still maintain the androgen receptor-pathway, which plays a central role for survival and growth of most castration-resistant prostate cancers. Many mechanisms induce the emergence of the castration resistant phenotype through this pathway. However some non-related AR pathways like neuroendocrine cells or overexpression of anti-apoptotic proteins like Hsp27 are described to be involved in CRPC progression. More recently, loss of expression of tumor suppressor gene, post-transcriptional modification using miRNA, epigenetic alterations, alternatif splicing and gene fusion became also hallmarks of castration-resistant prostate cancer. This review presents an up-to-date overview of the androgen receptor-related mechanisms as well as the latest evidence of the non-AR-related mechanisms underlying castration-resistant prostate cancer progression.

DNA repair mechanisms in cancer development and therapy

DNA damage has been long recognized as causal factor for cancer development. When erroneous DNA repair leads to mutations or chromosomal aberrations affecting oncogenes and tumor suppressor genes, cells undergo malignant transformation resulting in cancerous growth. Genetic defects can predispose to cancer: mutations in distinct DNA repair systems elevate the susceptibility to various cancer types. However, DNA damage not only comprises a root cause for cancer development but also continues to provide an important avenue for chemo- and radiotherapy. Since the beginning of cancer therapy, genotoxic agents that trigger DNA damage checkpoints have been applied to halt the growth and trigger the apoptotic demise of cancer cells. We provide an overview about the involvement of DNA repair systems in cancer prevention and the classes of genotoxins that are commonly used for the treatment of cancer. A better understanding of the roles and interactions of the highly complex DNA repair machineries will lead to important improvements in cancer therapy.