Cancer metastasis means certain cancer cells leave the original site they started and spread to other parts of the body. Once the cancer metastasis happens, surgery will no longer be an effective treatment solution; chemotherapy and other types of drug have to be given to the patients to control the growth of those cancer cells that have settled down at multiple places of the body, which will dramatically drive down the survival rate of cancer patients.
Drug resistance is another problem in cancer treatment. It happens when a chemotherapy or targeted therapy drug that works pretty well at the beginning of treatment fails to kill the cancer cells any more, and the cancers start to grow again or come back after they disappeared for a while during the treatment.
Oncologists and scientists have tried to find out what caused the metastasis and drug resistance for many decades. With the advance of technologies in gene sequencing and other tools of molecular diagnosis, the hidden reasons of these problems are emerging.
Tumor Heterogeneity is a scientific word describing the genetic complexity of the tumor. When examining the cancer cells from both the original site and metastatic sites, or even at the different locations of the same tumor mass from the same patient, scientists found out that the gene mutations and other types of genetic abnormalities are quite different.
Backed up by a solid body of research evidences, it is becoming clear that cancers are not made up of identical cells and not stand still. They keep evolving constantly. If gene mutations that drive the metastasis occur in certain subset of the tumor while evolving, that subset of cancer cells will gain the ability to break out from the primary mass and start to spread out. For the same reason, the initial mutations could be lost in certain cancer subsets, and the drugs that aim at those mutations as the targets won’t work well anymore, which results in the drug resistance and tumor recurrence.
The problems of metastasis and drug resistance caused by the Tumor Heterogeneity are getting tremendous attention from oncologists and cancer researchers. Clinical actions at multiple levels are being taken to address these important issues scientifically and clinically.
Gene analysis and molecular diagnosis tools, such as the Nex-Gen sequencing (NGS), “liquid biopsy”, are used more frequently to detect the heterogeneity and monitor their changes. The combination therapies are becoming more popular than the single drug treatment, which uses a combination of drugs that aim at multiple genetic and molecular targets and put the potential cancer subsets under control for longer time during to save the lives of patients.
More and continued research is needed for us to win the fight against the ever evolving cancers. Support NFCR’s cancer science program today so that we can get the critical research down.
Michael Wang, MD, PhD, Chief Science Officer, NFCR