Tumour progression (IMAGE) Garvan Institute of Medical Research Caption Each coloured ribbon represents a DNA barcode. As the tumour evolves, some cancer cells come to dominate the tumour, shown by the orange and red ribbons. This shows these cancer cells have a pre-existing ability to escape the immune system and can carry on growing, even after treatment. Credit Garvan Institute of Medical Research Usage Restrictions To be used only with this release License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.