DNA hypomethylation silences anti-tumor immune genes in early prostate cancer and CTCs.

Cancer is characterized by hypomethylation-associated silencing of large chromatin domains, whose contribution to tumorigenesis is uncertain. Through high-resolution genome-wide single-cell DNA methylation sequencing, we identify 40 core domains that are uniformly hypomethylated from the earliest detectable stages of prostate malignancy through metastatic circulating tumor cells (CTCs). Nested among these repressive domains are smaller loci with preserved methylation that escape silencing and are enriched for cell proliferation genes. Transcriptionally silenced genes within the core hypomethylated domains are enriched for immune-related genes; prominent among these is a single gene cluster harboring all five CD1 genes that present lipid antigens to NKT cells and four IFI16-related interferon-inducible genes implicated in innate immunity. The re-expression of CD1 or IFI16 murine orthologs in immuno-competent mice abrogates tumorigenesis, accompanied by the activation of anti-tumor immunity. Thus, early epigenetic changes may shape tumorigenesis, targeting co-located genes within defined chromosomal loci. Hypomethylation domains are detectable in blood specimens enriched for CTCs.

Noncanonical Wnt as a prognostic marker in prostate cancer: "you can't always get what you Wnt".

Introduction: Wnt signaling is important for normal development, cell proliferation, and cell differentiation. However, aberrations in the pathway can lead to tumorigenesis and cancer progression. Recent genome-wide studies have demonstrated the frequent occurrence of Wnt pathway alterations in prostate cancer. Although alterations in the canonical Wnt pathway in prostate cancer may have an impact on prognosis, recent studies suggest that the noncanonical Wnt pathway also plays an important role in disease progression and treatment resistance.Areas covered: We review the literature with regard to the potential prognostic significance of noncanonical Wnt signaling in prostate cancer. After a brief overview of the canonical and noncanonical Wnt pathways, we discuss the preclinical and clinical evidence for activation of Wnt signaling in prostate cancer. We focus on clinical evidence for noncanonical Wnt pathway components to serve as potential prognostic biomarkers.Expert opinion: Although many therapeutic options are available for men with prostate cancer, there remains an unmet need for prognostic and predictive biomarkers to precisely guide clinical management. Early evidence suggests that components of the noncanonical Wnt pathway may serve as prognostic biomarkers. However, prospective validation studies are necessary before these biomarkers can be routinely applied in the clinic.

Molecular analysis of circulating tumors cells: Biomarkers beyond enumeration.

Advances in our molecular understanding of cancer biology have paved the way to an expanding compendium of molecularly-targeted therapies, accompanied by the urgent need for biomarkers that enable the precise selection of the most appropriate therapies for individual cancer patients. Circulating biomarkers such as circulating tumor cells (CTCs) are poised to fill this need, since they are "liquid biopsies" that can be performed non-invasively and serially, and may capture the spectrum of spatial and temporal tumor heterogeneity better than conventional tissue biopsies. Increasing evidence suggests that moving beyond the enumeration of CTCs towards more sophisticated molecular analyses can provide actionable data that may predict and potentially improve clinical outcomes. In this review, we discuss the potential of molecular CTC analyses to serve as prognostic and predictive biomarkers to guide cancer therapy and early cancer detection. As technologies to capture and analyze CTCs continue to increase in sophistication, we anticipate that the potential clinical applications of CTCs will grow exponentially in the coming years.

Whole blood stabilization for the microfluidic isolation and molecular characterization of circulating tumor cells.

Precise rare-cell technologies require the blood to be processed immediately or be stabilized with fixatives. Such restrictions limit the translation of circulating tumor cell (CTC)-based liquid biopsy assays that provide accurate molecular data in guiding clinical decisions. Here we describe a method to preserve whole blood in its minimally altered state by combining hypothermic preservation with targeted strategies that counter cooling-induced platelet activation. Using this method, whole blood preserved for up to 72 h can be readily processed for microfluidic sorting without compromising CTC yield and viability. The tumor cells retain high-quality intact RNA suitable for single-cell RT-qPCR as well as RNA-Seq, enabling the reliable detection of cancer-specific transcripts including the androgen-receptor splice variant 7 in a cohort of prostate cancer patients with an overall concordance of 92% between fresh and preserved blood. This work will serve as a springboard for the dissemination of diverse blood-based diagnostics.