In November, the world鈥檚 first cloned baby could be born, if recent reports are to be believed. But cloning experts are horrified and say that even if the baby is healthy, the mother could be at a high risk of a rare invasive womb cancer.
Shock waves have reverberated around the world since New Scientist highlighted the claim of maverick Italian fertility expert Severino Antinori that one of his patients is pregnant with a clone.
According to Gulf News, he told a meeting in the United Arab Emirates that 鈥渙ne woman among thousands of infertile couples in the programme is eight weeks pregnant鈥�.
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But in addition to fears for the clone itself, worries have emerged about the future health of the mother. Richard Gardner, an expert on early mammalian embryo development who chaired the UK Royal Society鈥檚 working group on cloning, says that the mother could be at risk from choriocarcinoma, an unusual form of cancer unique to humans.
The cancer develops from the trophoblast, the part of an embryo that invades the womb wall and develops into the placenta. Though the causes are unknown, poorly regulated genes controlling the growth of the placenta seem to be the key.
Gene overdrive
Animal experiments have shown that these genes remain switched on in cloned embryos when they should be silenced by a chemical masking process called 鈥渋mprinting鈥�. This means that important genes linked to the development of the placenta could go into overdrive, accelerating its growth and posing high risks to mothers.
鈥淭he human has the most invasive placenta to start with,鈥� says Gardner, a zoologist at the University of Oxford. 鈥淚f placental growth goes awry, there鈥檚 a greater propensity for this problem to emerge in humans than in other animals.鈥� He admits that while the risk is only theoretical, people have paid far too little attention to it, focusing instead on the fate of the clone itself.
Barry Hancock, director of a clinic at Weston Park Hospital in Sheffield that specialises in the treatment of trophoblastic cancers, agrees that abnormal imprinting in the genes of cloned human embryos may increase a mother鈥檚 risk of the disease. 鈥淏ut it鈥檚 a theoretical risk,鈥� he says.
Whatever the dangers, many people doubt Antinori鈥檚 claims and want to see some solid proof. 鈥淚t鈥檚 very difficult to know what, if anything, is true,鈥� says Harry Griffin, head of communications at the Roslin Institute near Edinburgh where Dolly the sheep was cloned.
