Dr Elizabeth Duncan
Cancer. It is a small word, but one that has a big meaning for a lot of people. Most of us know someone who has had cancer, or are cancer survivors.
As a geneticist I can sometimes have a dispassionate view of the world around me, but last night as Jessica Wapner read an excerpt from her book “The Philadelphia Chromosome” I almost cried. Jessica began her talk with a poignant tale of a man named Gary Eichner. Gary was diagnosed with chronic myeloid leukemia (CML) at the age of 43. CML causes the bone marrow to make too many white blood cells. If Gary had been diagnosed 20 years ago he would have had a poor prognosis, almost no chance of surviving 5 years. Now, thanks to a drug called Gleevec (and its derivatives), Gary has a 95% chance of surviving 5 years and a 90% chance of surviving 10 years.
This drug revolutionized our approach to cancer medicine. For the first time scientists were able to discover the genetic cause of a cancer and design a drug to specifically target that cause. One of the cells in Gary’s bone marrow had made an error while replicating. This error caused a little piece of chromosome 9 to swap with a piece of chromosome 22 making a new protein. This new protein (called BCR-ABL) was telling the white blood cells to divide, a process that is stopped by Gleevec.
The genetic cause of this cancer was first discovered in 1959, but we didn’t really understand it until the 1990’s. A lot has changed since then. We now have the sequence of the human genome and genome sequencing is now cheaper and faster than ever. We can now look for the root-causes of particular cancers, find what changes have occurred in the DNA of a cancer. Professor Ian Morison, a clinical haematologist at the University of Otago, has used the new genome sequencing technologies to find a chromosomal abnormality in a local family that causes this family to be more susceptible to a particular kind of blood cancer. In clinics in the USA and Europe genetic tests are being used routinely for some kinds of cancer. This information is then used to determine the best course of treatment.
The talk by Jessica and by Professor Ian Morison, hosted by Genetics Otago at Toitu (Otago Settlers Museum), highlighted the immense power of new genetic technologies for finding the root cause of cancers and other genetic diseases. Knowing the genetic changes that cause particular cancers will not only allow doctors to give patients the most effective treatment but will also provide targets to find novel drugs.
The talk by Jessica Wapner and Professor Ian Morrison was part of the inaugural Genetics Week, hosted by Genetics Otago .