Research coming from the Fred Hutchinson Cancer Research Center and Johns Hopkins Medical Institute concludes that the deadly spreading of cancer occurs in clusters rather than single cancer cells.
It was thought that when cancer migrates from one organ to the next, a single cancer cell has escaped from the original organ and has settled in another organ to create a secondary tumor. Now research from the above institutes describes migrating tumor clusters and their unique molecular signatures in the journal PNAS, pointing to new targets in cancer drug development.
In a mouse model of breast cancer that consistently spreads to the lungs the researchers were able to track the migrating cells. From their screening of these cells they found a protein called keratin 14 to be highly abundant in these cells--important for their marauding behavior.
They also scanned the expression of genes by RNA sequencing and uncovered unique genes to the migrating cancer cells. Important genes that were highly expressed included genes involved in adherence of one cell to the next making it easier to travel as a cluster and to stick to other organs, while repressed genes included those involved in antigen presentation--making it easier to go unnoticed by the host's immune system.
"We need to do more studies to test these hypotheses and, ultimately, push these findings forward to develop new therapies for metastatic breast cancer," said Kevin Cheung, who is a postdoctoral researcher under senior author Andrew Ewald.
"Of all stages of breast cancer, metastasis remains the hardest to treat. If you think of this study as a roadmap, then the work in my laboratory is now directed at creating the battle plan to combat this challenge."