Professor Birch said that the pattern of incidence had implications for discovering and understanding the causes of teenage and young adult (TYA) cancers.
"It is a frequently held view that there is no such thing as 'teenage cancers' in the sense that embryonal tumours typify cancers of early childhood. Our research shows that there is, and, having identified the very specific types that are TYA cancers, we are able to find clues as to why teenagers and young adults get cancer. These point to infections, adolescent growth spurts, hormones and other growth and development factors as among the most probable causes.
"Considering these 'true' TYA cancers, there is quite a lot of evidence suggesting that infections, particularly the pattern and timing of infections, are causally involved in Hodgkin lymphoma. While the Epstein-Barr virus has been implicated already, this would only account for a proportion of cases. Other infectious agents involved in causation of Hodgkin lymphoma have yet to be discovered.
"Osteosarcoma is a tumour that occurs predominantly in the long bones of the legs (73% of all cases) and arms (10% of all cases) and has a very pronounced peak of incidence during the teenage years. There is a slightly earlier age peak of incidence in girls than in boys, coinciding with the adolescent growth spurt. We can speculate that pre-cancerous genetic changes occur in the bone tissue during childhood and that during periods of rapid growth in teenagers, further genetic damage occurs, resulting in conversion of pre-malignant cells to malignant, leading to the formation of a bone cancer. A similar age of onset pattern is also seen for Ewing sarcoma of bone and the causal mechanisms may be related.
"Most testicular cancers, at whatever age, are germ cell tumours and it is well known that these show a peak incidence in young adult males. In contrast, most ovarian cancers are carcinomas (ca
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Contact: Emma Mason
wordmason@mac.com
44-077-112-96986
Teenage Cancer Trust
29-Mar-2006