Pregnant women can transmit cancer to fetus
Published 15 October, 2009, 10:47
Edited 15 October, 2009, 14:01
Japanese scientists have managed to prove that a mother can transmit cancer to her fetus. Only a handful of such cases have been suspected, and none have been verified until now.
Usually, any cells from the mother, including cancerous metastases, are blocked by the placenta before they can reach the fetus. But sometimes the defense fails, reports Science journal.
In early 2007, a 28-year-old woman in Japan gave birth to a girl. A month later the mother died from uncontrollable bleeding and doctors diagnosed leukemia shortly before she passed away.
Later the baby, who was 11 months old at the time, developed a huge tumor in her cheek. It was suspected to be sarcoma first, but a biopsy revealed it to have leukemic origin.
The case was studied by cell biologist Mel Greaves of the Institute of Cancer Research in Sutton, Surrey, United Kingdom, who studies transmissible cancers. Greaves and her colleagues discovered several pieces of evidence backing the theory that cancer was transmitted from mother to fetus.
They found incipient cancer cells in blood samples taken from the girl at birth. Further study showed that the baby’s tumor had an identical DNA signature to the mother’s disease. The tumor also had almost no genetic material from the father, which suggests that cancer developed in the mother and infected the baby, rather than vice versa.
The team also found out how cancer managed to slip though the placental barrier. The disease lacked a portion in its DNA, which produces surface markers that immune cells latch on to. Greaves described it as being “immunologically invisible”.
The study is not likely to change how pregnant women are screened or cared for. Such cases are extremely rare, with only a few dozen suspected over the last century and a half, but it gives medics a new insight into how cancer interacts with the immune system.
The Japanese girl studied by Greaves and colleagues was successfully treated and is alive and well.
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