A drop of blood or a chunk of tissue smaller than the period at the end of this sentence may one day be all that is necessary to diagnose cancers and assess their response to treatment, say researchers at the Stanford University School of Medicine.
In a study to be published April 12 in the online version of Nature Medicine, the scientists used a specialized machine capable of analyzing whether individual cancer-associated proteins were present in the tiny samples and even whether modifications of the proteins varied in response to cancer treatments.
Although the study focuses on blood cancers, the hope is that the technique might also provide a faster, less invasive way to track solid tumors.
“Currently we don’t know what’s going on in a patient’s actual tumor cells when a treatment is given,” said oncologist Alice Fan, MD, a clinical instructor in the division of oncology at the medical school. “The standard way we measure if a treatment is working is to wait several weeks to see if the tumor mass shrinks. It would really be a leap forward if we could detect what is happening at a cellular level.”
Fan, the lead author of the study, performed the research in the laboratory of senior author Dean Felsher, MD, PhD, associate professor of medicine and of pathology and the leader of the Stanford Molecular Therapeutics Program.
“This technology allows us to analyze cancer-associated proteins on a very small scale,” said Felsher, a member of Stanford’s Cancer Center, who studies how cancer genes called oncogenes initiate and influence tumor progression in many types of cancers. “Not only can we detect picogram levels – one-trillionth of a gram – of protein, but we can also see very subtle changes in the ways the protein is modified.”
Variations in the way a protein is modified, or phosphorylated, can affect how it functions in tumor progression. Cancer cells often evade common therapies by rejiggering their levels of protein expression and degrees of phosphorylation. Analyzing repeated small samples from a tumor undergoing treatment may allow doctors to head off rogue cells at the pass before they have a chance to proliferate into a more resistant tumor or to identify patients likely to fail standard approaches to treatment.
Although Fan and Felsher focused on lymphoma and leukemia in this study, Fan is expanding her investigations to include head and neck tumors, which tend to be relatively accessible for cell sampling. Both researchers caution that more research must be conducted before the technology is widely available clinically.
The study was supported by the National Cancer Institute, the Burroughs Welcome Fund, the Damon Runyon Foundation and the Leukemia and Lymphoma Society.
Source: Stanford University Medical Center, USA