(Source: Stanford University) – Imagine: You pop a pill into your mouth and swallow it. It dissolves, releasing tiny particles that are absorbed and cause only cancerous cells to secrete a specific protein into your bloodstream. Two days from now, a finger-prick blood sample will expose whether you’ve got cancer and even give a rough idea of its extent.


That’s a highly futuristic concept. But its realization may be only years, not decades, away.

Stanford University School of Medicine investigators administered a customized genetic construct consisting of tiny rings of DNA, called DNA minicircles, to mice. The scientists then showed that mice with tumors produced a substance that tumor-free mice didn’t make. The substance was easily detected 48 hours later by a simple blood test.

A paper describing the findings of this proof-of-principle study were published online Feb. 23 in the Proceedings of the National Academy of Sciences.

The technique has the potential to apply to a broad range of cancers, so someday clinicians might be able not only to detect tumors, monitor the effectiveness of cancer therapies and guide the developments of anti-tumor drugs, but — importantly — to screen symptom-free populations for nascent tumors that might have otherwise gone undetected until they became larger and much tougher to treat.

Triggering an unambiguous biomarker

The hunt for cancer biomarkers — substances whose presence in an individual’s blood or urine flags a probable tumor — is nothing new, said the study’s senior author, Sanjiv “Sam” Gambhir, professor and chair of radiology and director of the Canary Center at Stanford for Cancer Early Detection. High blood levels of prostate-specific antigen, for example, can signify prostate cancer, and there are also biomarkers that sometimes signal ovarian and colorectal cancer, he said.

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Senior research scientist John Ronald, PhD, is the lead author of the paper. Other Stanford co-authors are graduate student Hui-Yen Chuang and  research scientists Anca Dragulescu-Andrasi, PhD, and Sharon Hori, PhD.

The study was funded by the Canary Foundation, the National Cancer Institute (grants P50CA114747, R01CA082214 and RO1CA13548), the Ben and Catherine Ivy Foundation and the Sir Peter Michael Foundation.

Information about Stanford’s Department of Radiology, which also supported the work, is available at http: http://radiology.stanford.edu/.