How close are we to winning the fight against cancer?
“Gotta catch ‘em all before it’s too late” is not just a creative twist on the Pokémon slogan. It’s what oncologists try to achieve on a daily basis: improving their patients’ survival rates by detecting and killing all tumor cells that may or may not have metastasized, or spread via bodily fluid systems – such as the blood or lymph nodes – throughout the body. Though surgical procedures to combat cancer have made marked improvements over time, many cancer patients are unable to reduce chances of mortality simply because the tumor cells were discovered too late – too late for medical treatment to have any positive effects.
Scientists, however, have recently developed artificially engineered biomarkers that could allow the early detection of tumor cells in mice. Because tumor cells rarely release markers into the blood, it is very difficult to determine what stage of cancer the patient is in, and, more fundamentally, whether or not an individual even has tumor cells. As a solution to this problem, scientist Sanjiv Gambhir and his co-workers at Stanford University designed tumor-detecting “minicircles” that can be injected into the blood. The blood releases an enzyme that indicates the presence of cancer in the body. Smaller than bacterial plasmids, these minicircles possess reporter genes that cannot be found in adult tissues; if reacted with survivin, a tumor-specific promoter, the reporter genes release a protein called secreted embryonic alkaline phosphatase (SEAP), which therefore signifies the presence of tumor cells.
These minicircles were labeled successful – at least for the time being – when they were injected into a sample of tumor-bearing mice; 92 percent of the mice were reported to have produced SEAP within the course of three days to two weeks (Detecting cancers through tumor-activatable minicircles). Many scientists have already raised doubts about their compatibility with the general population, especially because the biomarkers have not yet been tested on people. According to Harald Mischak from the University of Glasgow, the method is not specific enough to identify small cancer cell colonies or exactly where the tumors are located, and this lack of specificity merely causes unnecessary anxiety in patients.
Regardless of the problems being brought to light, the minicircles are still in the process of being refined and improved. In fact, scientists are trying to find mechanisms to make the biomarkers more organ-specific and design different ways they could be inserted into the body besides systemic injection. For now, as Gambhir says, the biomarkers are a “fairly modular” form of tumor detection that allows for the signals people need in order to effectively “catch ‘em all.”
Rood, Jenny. “Engineered Biomarkers Could ID Cancer Cells.” TheScientist: Exploring Life, Inspiring Innovation. TheScientist, 23 Feb. 2015. Web. <http://www.the-scientist.com/?articles.view/articleNo/42229/title/Engineered-Biomarkers-Could-ID-Cancer-Cells/>.
Detecting cancers through tumor-activatable minicircles that lead to a detectable blood biomarker, Ronald et. al <http://www.pnas.org/content/early/2015/02/17/1414156112.abstract>