The work I’ve done for this presentation is a review of registry papers. The more you look into, the more confusing it seems to be because, in fact, in many cases germ cell tumour diagnosis is based on markers, based on radiographic evidence and not always on histology. So it may be that some of the discrepancy we see between registries and some of the theories are related to factors, underreporting for example.

However, we know and it’s known since a long time, that the incidence of germ cell tumour in the brain is much higher in Asian countries, particularly Japan, Korea, China, Thailand and Hong Kong.  We have data on these countries which suggests that the incidence is three to four times higher compared to western countries. Now, there have been some controversial papers and a particular paper a year and a half, two years ago, which has changed this dogma and says, no, the incidence is the same. We had some comments this morning as part of the discussion which suggest that this paper that compared two different registries, one in Japan and one in the States, in fact didn’t pick the right registry. There are issues with reporting germ cell tumour in the brain, clearly.

I went to a talk on Kawasaki disease a few years ago and I saw this map of Kawasaki disease. This was a story about the incidence and it was also about the wind and about pollution. I was thinking when I was listening to this talk, I said, ‘But if I change the word Kawasaki to germ cell tumour I could give exactly the same talk because the map is the same.’ It was just all around China, Korea, Japan. We know that this is quite a classical feature of Kawasaki disease.

So when I did this work on the epidemiology of germ cell tumours I tried to look at some ideas and I found a paper on germ cell tumours in animals. In fact this was a white fish experience where it’s related, because this was a sort of epidemiology study, that identified three fish out of five hundred who had intracranial germ cell tumour which is a very, very high incidence. The explanation from the author was it’s due to the pollution. So, again, something which is new into the epidemiology or some additional thoughts.

Until now most of the rationale for the high incidence was supposed to be related to an ethnic predisposition in the Asian population. Now what’s interesting now is to look at the diaspora or the migration of the Asian population in some parts of the country and particularly in North America where there is a significant proportion of Asians from Hong Kong, from Korea, from China, inland China, who have migrated. And ideally it would be superb to look at the first, second and third generations to see if there is any change in the incidence of germ cell tumour because if we do that we have a better idea whether it’s a genetic predisposition or whether it’s environmental or both.

There is an Inuit registry in Saskatchewan specific for the Inuit population. It’s not only about cancer but it collects information on cancer. I remember, because we had a child with a germ cell tumour, an intracranial germ cell tumour, that reported to this registry. By chance I had the opportunity to discuss with the people from the registry and they said that the incidence of intracranial germ cell tumour was also very high in the Inuit population. Which suggests that, because we know that the Inuit population came through the Strait of Bering 10-15,000 years ago, that if this is the case there is a higher incidence, they came from Asia so it clearly suggests that the genetic predisposition is the main driver in the high incidence of intracranial germ cell tumours.