The researchers proved the possibility of the fetus had inherited the cancer cells that are owned by mother even though the number of cases are very rare. In fact, according to the theory, the immune system should be able to prevent cancer cells into the fetal blood circulation network through the placenta.

BBC News website, which cites British research team study of the National Academy of Sciences, said there are 17 cases of mothers and children who suffer from the same cancer (usually leukemia or melanoma). This study focuses on mother and child with leukemia.

The researchers used the technique of genetic fingerprinting tests to prove the leukemia cells derived from fetal’s mother. The result, leukemia cells both have a cancer gene that has mutated. Fetal immune system did not have the ability to recognize cancer cells as foreign body. As a result, when the cell is entered, there was no resistance at all.

Chairman of the research team, Professor Mel Greaves, from the Institute of Cancer Research said cancer cells can freely cross the placenta into the fetus because it is not considered dangerous by the immune system. “However, this case is very rare so the chance of transmission of cancer cells into the fetus’ mother is still little,” he said.