AORTIC 2011, Cairo, Egypt 30 November–2 December 2011

Ethnic variations in genetic basis of cancer

Dr Pedro Fernandez – Stellenbosch University, South Africa

I’ve been awarded one of the BIG CAT grants, so that’s a Beginning Investigator Catalytic grant, and it’s a small grant but it’s a start-up grant so the idea is to catalyse small research that will go into much bigger research. So I’ll be presenting some of my work about what we’ve been doing so far, here. Unfortunately it’s early stages of our work.

We look at DNA samples, so we look at the genetics and we look chromosome by chromosome. Essentially you want to look at all the chromosomes and then try to identify regions that seem to be associated with only people that have the disease versus if you look at the general population, they don’t have those specific genetic variations. But our study is essentially slightly smaller than looking at all the chromosomes, so we selected a number of chromosomes that we’re looking at and these are basically trying to verify studies that have been done in North America, Europe and a few African populations. So that’s really our approach.

Are these the same chromosomes in spite of race?

Yes, that’s one of the questions we tried to answer. Most of these studies have been done in Caucasian populations and so with prostate cancer, it’s quite genetic in that it seems to be higher in populations of African descent, yet all the studies seem to be focussed on Caucasian populations. So we’re trying to build a panel where we’re looking at African populations and seeing why there’s a high prevalence of prostate cancer in men of African descent. But the nice thing about our population is because we have a span of different populations, African, essentially European and combinations of the two, we can tease out where the genetic effects are coming from, whether it’s coming from Europe or whether it’s coming from Africa, so that makes it quite unique in our study. The idea is really to expand it to other African populations.

What can be done once this is understood?

Yes, that’s the million dollar question, isn’t it? As geneticists we like to say… I do recall a few years ago when a number of studies had found very much what we’re looking for. They said, “We’ll find the gene that causes the disease in the next five years,” it’s not that simple. Prostate cancer is a combination of a number of genes and you’ve got to consider the effects of environment, diet and lifestyle. So essentially what we’re trying to do is look at these genes, what is it about these genes that where, if you look at one population, the environment does not have an effect, but in another population where the combination of genetics and environment seem to be at high risk? And so that will be the million dollar question. It’s some way away but we believe looking at African populations we can get closer to the answer because in the past there have been many answers but also many questions have been raised. So hopefully in African populations we can narrow it down to a small region and say, “Right, instead of looking at the broad picture we’re looking at a much smaller region to identify a causal or many causal genes.”

When will the data be published?

Yes, the grant is spread over two years and so essentially we should start reporting from after the second year, which ends the end of 2012. In most cases grants run up about two years after the grant funding has ended, they give you a grace period to do that, but we’ve had sufficient data to get quite a number of fairly good reports out fairly soon. I guess somewhere in the region towards the end of next year.