Genetic Diversity in Cancer Cells

A recent study performed by Stefanie Jeffrey, MD (professor of surgery and chief of surgical oncology research at the Stanford University School of Medicine) and her research team has brought new insight into the heterogeneity of cancer cells and how we may be able to treat them. Through the use of two relatively new technologies (the Magsweeper and the PCR microfluidic chip) the researchers were able to isolate and sequence 95 genes from the circulating tumor cells of 50 patients with breast cancer. Circulating tumor cells, or CTCs, are a rare type of red blood cell believed to help disseminate cancer from organ to organ throughout the body. The results of the study reflected a surprising amount of genetic diversity in CTCs. “In the patients, we ended up with a subset of 31 genes that were most dominantly expressed,” said Jeffrey. “And by looking at levels of those genes, we could see at least two distinct groups of circulating tumors cells.” The researchers were able to divide the CTCs into as many as five groups, depending on which genes were used, each with different combinations of genes turned on and off. The diversity among these CTCs suggests that a single biopsy of a patient’s tumor does not necessarily indicate all of the molecular changes driving the cancer forward and helping it to spread. As we continue in our efforts to learn more about cancer and how to treat it, we must keep in mind that different cells may require different therapies.

According to an article published on the Stanford University School of Medicine website, this study is “the first time that scientists have used high-throughput gene analysis to study individual CTCs, and opens the door for future experiments that delve even more into the cell diversity. The Stanford team is now working on different methods of using CTCs for drug testing as well as studying the relationship between CTC genetic profiles and cancer treatment outcomes. They’ve also expanded their work to include primary lung and pancreatic cancers as well as breast tumors.”

Sources

1.     Eurekaalert.com: “Not all tumor cells are equal: Stanford study reveals huge genetic diversity in cells shed by tumors” < http://www.eurekalert.org/pub_releases/2012-05/sumc-nat050312.php>

2.     Med.stanford.edu: “Not all tumor cells are equal: Study reveals genetic diversity in cells shed by tumors” < http://med.stanford.edu/ism/2012/may/jeffrey.html>

3.     Plosone.org: “Single Cell Profiling of Circulating Tumor Cells: Transcriptional Heterogeneity and Diversity from Breast Cancer Cell Lines” < http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0033788>