Scientist Solve 100-year Cancer Puzzle
12 October 2009 - ICR scientists and colleagues in Japan have proven for the first time that it is possible in rare cases for cancer cells to cross the placenta from mother to child. The study was published in Proceedings of the National Academy of Sciences.
In around 30 previously known cases over the past 100 years, a mother and infant have appeared to share the same cancer, usually leukaemia or melanoma, raising suspicions that cancer spread through the womb was possible.
But there was no genetic evidence to support this theory, and scientists did not know how it could happen as the baby’s immune system should have recognised and destroyed any invasive cancer cells that were of maternal – and therefore ‘foreign’ – origin.
The ICR scientists carried out advanced genetic fingerprinting of both patients’ leukaemic cells and found they carried a mutated cancer gene (BCR-ABL1). But the infant had not inherited this gene so could not have developed this type of leukaemia in isolation.
They next discovered that the cancer cells in the infant had a deletion mutation in the region that controls expression of the major histocompatibility locus (HLA). As HLA molecules distinguish one individual’s cells from another, the absence of these molecules on the cancer cells meant the child’s immune system would not have recognised they were foreign.
ICR Professor Mel Greaves said the team was pleased to have solved the long-standing puzzle, but stressed that the chances of any pregnant woman with cancer passing it on to her child were remote.