Editors' ChoiceCancer

Brain Tumor Diagnostics Go Micro

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Science Translational Medicine  02 May 2012:
Vol. 4, Issue 132, pp. 132ec77
DOI: 10.1126/scitranslmed.3004205

MicroRNAs (miRNAs) play pivotal roles in aspects of normal cellular function, including development, differentiation, and homeostasis. Interestingly, miRNAs may also play a central role in cancer biology by acting as putative tumor suppressors or oncogenes. Given that miRNAs are readily detected in nearly every body fluid through polymerase chain reaction (PCR)–based assays and can be cancer-specific, Teplyuk and colleagues have sought them out as potential biomarkers to diagnose and follow disease burden in glioblastoma (brain cancer) patients.

One of the challenges in developing a robust biomarker for patients with brain tumors is the blood-brain barrier, which is thought to prevent the release of tumor-specific proteins and nucleic acids into the circulation. To circumvent this, Teplyuk et al. profiled several candidate miRNAs in the cerebrospinal fluid (CSF) of over 100 patients with either glioblastoma or cancer metastasis to the brain. They found that tumor-specific miRNA could be detected and quantified by using PCR-based assays in ~90% of brain tumor cases, suggesting that these miRNAs could be noninvasive indicators of cancer presence. Panels of miRNAs could be used to differentiate glioblastoma from metastatic lesions—an important consideration for cancer treatment, which currently can only be assessed with imaging. In a small cohort of patients, the levels of miRNA could be followed longitudinally and correlated well with disease burden over several months. Importantly, the miRNAs queried in this study were not detectable in the CSF of patients with noncancerous brain lesions.

Currently, patients and health care providers are forced to rely almost exclusively on radiographic findings to detect and monitor brain tumors. Having an adjunct biomarker, such as miRNA, would help guide clinical decision-making. Given that approximately one in three cancer patients will develop brain metastases, it will be interesting to see whether specific miRNA profiles can be generated to capture all tumor types. As our understanding continues to expand, the potential applications for miRNAs are proving more numerous than micro.

N. M. Teplyuk et al., MicroRNAs in cerebrospinal fluid identify glioblastoma and metastatic brain cancers and reflect disease activity. Neuro-Oncology. 19 April 2012 (10.1093/neuonc/nos074). [Abstract]

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