14 DAY TRIAL // One of the reasons why cancer oftentimes relapses is that treatments do not kill off its stem cells, the ones that promote tumor growth in the first place. In a new study, scientists found the genetic fingerprint of these cells, raising hopes that new treatments will be able to target these cells specifically.
Just like regular stem cells, which contribute to replenishing cells in every type of tissue, cancer stem cells (CSC) play exactly the same role in tumors. If chemotherapy or radiotherapy kills off diseased cells, CSC differentiate into new ones, allowing the tumors to recover, and the cancer to relapse.
Therefore, finding a way of accurately pinpointing the location of CSC has been a long-term goal for oncologists. Scientists at the Harvard University Medical School (HMS) say that such a fingerprint may have already been found through their new research.
Their investigation involved a rigorous analysis of genetic expression patterns encountered across multiple forms of cancer. Details of the results were published in the August 21 issue of the esteemed journal Genome Biology.
In the paper, entitled “A gene expression profile of stem cell pluripotentiality and differentiation is conserved across diverse solid and hematopoietic cancers,” the group highlights the possibility of developing new types of treatments based on the recently-identified genetic profile.
During the investigation, the team uncovered a series of genes that are expressed in very particular manners inside normal stem cells. However, they are also expressed in very much the same way in numerous types of cancers, including those affecting the brain, blood and epithelium.
“In other words, from the perspective of which genes are being expressed, the cancers always looked like their normal tissue counterparts, plus a fraction of the stem cell 'signature' that we identified,” explains Isaac Kohane, the senior author of the new study.
“This signature may therefore serve as a starting point for therapeutic design,” adds the expert, who is the Lawrence J. Henderson professor of pediatrics at HMS and the Boston Children's Hospital, and also the co-director of the Center for Biomedical Informatics at the Countway Library of Medicine.
Another important discovery the team made is that the intensity of the signature left behind by CSC can be correlated to how advanced the cancer is. The strongest genetic fingerprints were associated with stage IV (metastatic) cancers.
“Specifically, we may be able to use this stemness measure to identify tumors that present as low- or mid-grade under a microscope but are 'under the hood' about to become highly aggressive,” research fellow and first author, Nathan Palmer, concludes.