Leukaemia study points to pre-birth factors in disease

By ANGELA GREGORY

Cancer researchers say they have more evidence pointing towards pre-birth causes of childhood leukaemia.

The development adds weight to theories that parents have little to fear from children's exposure to environmental influences such as cellphone towers or high-voltage power lines.

Researchers at Otago University's Cancer Genetics Laboratory have had their findings published in the American medical journal Blood.

One of the researchers, Dr Ian Morison, expected the findings would produce a big rethink on childhood cancer as they continued to point towards pre-birth causes of acute lymphoblastic leukaemia (ALL).

Dr Morison said the research raised the possibility that genetic effects might predispose children to ALL before they were even conceived, through a vulnerability in the father's sperm.

That vulnerability could lead to a failure in the regulation of the growth rate of developing blood cells. "The handbrake is missing," he said.

After analysing DNA from more than 60 affected New Zealand families, the team found that the genetic damage influencing developing lymphoblasts (blood cells) was occurring overwhelmingly on the maternal copy of the involved gene.

That indicated that the corresponding paternal copy had an "Achilles' heel" preventing it from acting as an effective backup.

Dr Morison said other studies continued to show that environmental factors played a part in leukaemia, but his team's research indicated those factors were likely to involve the parents' lifestyle.

"It is unlikely that children's exposure to cellphone towers, high-voltage power wires or any other environmental factor has any bearing on their chances of developing this disease."

Dr Morison said it was critical to find out if all sperm had the Achilles' heel.

If it developed only in some men, it raised the question of what the fathers of children with cancer had been exposed to three or four weeks before conception.

If all men had the weakness, the attention would shift to influences on the developing foetus.

nzherald.co.nz/health