Otago Researchers Make Kidney Tumour Breakthrough

Otago Researchers Make Kidney Tumour Breakthrough

Reason for differing Wilms¡¦ tumour incidence rates among Asians and Caucasian discovered

An international research team led by New Zealand¡¦s University of Otago has discovered the reason why Caucasian children are twice as likely to develop kidney tumours than their Asian counterparts.

The finding, published in the latest edition of the prestigious Lancet medical journal, could have implications for future drug treatment for, and the prevention of, Wilms¡¦ tumour and other major cancers.

Funded by the Health Research Council, the study was carried out by Drs Ryuji Fukuzawa, Ian Morison and Patrick Dwyer, and led by Professor Tony Reeve from the Cancer Genetics Laboratory of the University of Otago¡¦s Department of Biochemistry.

¡§It has been noted for many years that the incidence of Wilms¡¦ tumour varies widely across ethnic groups, being much lower in Asian than in white populations,¡¨ says Professor Reeve. ¡§There are between six and nine new cases of Wilms¡¦ tumour in New Zealand each year, with most cases occurring in children under the age of seven years.

¡§Ten years ago our team made a breakthrough when we discovered that Wilms¡¦ tumour can occur following an error in an imprinting mechanism ƒ{ a normal epigenetic process where one set of genes is ¡¥turned off¡¦. Then in 2001 we went on to discover that Asian and Caucasian tumours have different appearances under the microscope.

¡§Since these discoveries we suspected that the tumour mechanism might account for the differences, so we decided to find out for sure.¡¨

Professor Reeve continues: ¡§What we¡¦ve discovered in our latest research is that these tumours are not the result of some genetic mutation. Rather, a separate epigenetic molecular mechanism, which is a process where certain genes are marked for activity during embryonic development, is implicated in up to half of the cases involving Caucasian children. Surprisingly this mechanism is absent in Asians, accounting for why the population has one half the rate of this disease than Caucasians.¡¨

Furthermore, it appears that Wilms¡¦ tumour cases involving Indian or South-Asian children are similar to those of other Asians. ¡§However, more work needs to be done to confirm this,¡¨ he says. Wilms tumour accounts for over 90 per cent of kidney cancers in children and teenagers, and four per cent of all childhood cancers. Named after Dr Max Wilms who first described it, the cancer is also known as nephroblastoma. ¡§Wilms tumour is one of the success stories of cancer in that it is curable in over 85 per cent of cases,¡¨ according to Professor Reeve. ¡§However, what this new information suggests is a way of specifically targeting that route [this mechanism] to counter the disease. More importantly, it tells us something about the fundamental biology of this kind of cancer, and about a mechanism that is found in many of the common adult cancers ¡V breast, colon, lung.¡¨

Professor Reeve and his team are now setting their sights on exploring the genetic variations between populations which lead to a difference in the epigenetic mechanisms.

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