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Embryo Screening for Breast Cancer Genes Catholic Church Says Research Proposals Are 'a Step Too Far'

Posted on: Tuesday, 26 April 2005, 09:00 CDT

WOMEN undergoing IVF treatment could soon have the option of selecting babies that lack breast cancer genes.

A first step towards screening embryos for the two mutant genes most associated with inherited breast cancer has been taken by a pioneering group at University College London, it was revealed yesterday.

The team, led by Professor Ian Jacobs, is sending out questionnaires via clinical geneticists asking women with a known family history of breast cancer if they would back the move.

If the answer is yes, they will then develop a protocol, or set procedure, that could be introduced into suitable clinics within four to six months.

Last night, however, a spokesman for the Catholic Church in Scotland said it was "a step too far".

Pre-implantation genetic diagnosis (PGD) is the screening of in- vitro fertilisation embryos for inherited disorders. Doctors take a single cell from the embryo at an early stage, when it is a cluster of no more than six to eight cells.

Tests on that cell are then conducted to see if it carries genetic mutations for a particular disorder. If it does, the embryo is not used to make a pregnancy. Instead, it is discarded and another embryo is chosen which has been given the all-clear.

PGD has already been used to screen out mutations associated with a number of inherited conditions, such as cystic fibrosis, Huntington's disease, haemophilia and Duchenne muscular dystrophy.

However, its application to cancer is still very limited. This is because most cancers are caused by a complex combination of genetic and environmental factors.

But in the 1990s, scientists discovered two genes - BRCA 1 and BRCA 2 - that appear to be responsible for the vast majority of inherited breast cancers. It is these genes that could now be targeted in a new PGD test for at-risk women wanting to have a baby.

Dr Siobhan Sengupta, of the centre for pre-implantation genetic diagnosis at UCL, said:

"As part of our programme a section of our group is undertaking a study which involves sending out questionnaires to people who have a family history of breast cancer or are known to be carriers of these genes.

"If those affected by BRCA 1 and 2 feel that PGD is an option for them then we will develop protocols. But at the end of the day, it's all about patient choice."

The questionnaires will ask patients not only for their views on PGD for breast cancer genes, but also where they stand on aborting foetuses found to have BRCA 1 and 2.

Dr Sengupta said: "Individuals have very different opinions about this. Some would consider that selecting an embryo that does not carry the mutation is a more acceptable option than terminating an ongoing pregnancy."

Inherited breast cancers affect only about 5-per cent of the 40,000 women diagnosed with the disease each year in the UK.

But if a woman has either a mutated BRCA 1 or 2 gene, or both, she is 80-per cent more likely to develop breast cancer.

Assessing patient demand is always a first step before developing a new PGD test. Work on developing a protocol will only begin if patients give the idea their vote of approval.

A spokesman for the Catholic Church in Scotland said last night: "However wellintentioned this proposal is, in reality it means granting doctors the power of life or death over embryos. We would consider this to be a step too far."

Source: Herald, The; Glasgow (UK)

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