A recent study by a Brandeis biologist and two of his students sheds some light on what causes healthy cells to become cancerous. Professor James Haber, who was inducted into the National Academy of Sciences last spring, worked with grad student Wade Hicks and 2009 graduate Minlee Kim to research the process of repairing DNA damage, which they hold responsible for the rapid levels of mutation that characterize cancer cells.
[C]ells that are showing the very earliest signs of cancer start to have errors in the DNA replication process. To fix this, the cells use a number of methods to repair the damage, one of which is known as gene conversion.
Gene conversion repairs the break in the DNA strand by using an almost identical sequence from elsewhere in the cell’s DNA, providing a template from which the original strand can be reconstructed. Although this was once thought to be a mostly error-free process, the new study actually suggests it leads to a far greater number – about 1,400 times the usual amount – of DNA mutations than would otherwise be expected. Once these mutations affect the various genes that provide the cell’s ability to control its own growth, the cell quickly becomes cancerous.
Thus, tumors form where there was once healthy tissue. Understanding this process is the first step in determining how to correct it and slow the rate at which healthy cells become cancerous. Congratulations to Dr. Haber and to Wade and Minlee for publishing this important study and for working to ease the pain and suffering of so many people. As an undergraduate, I find it easy to forget that Brandeis is a research institution as well as a school. It’s gratifying to remember that so much positive work is being done at our university.