Titanium rings containing a panel of glass were implanted into the abdominal wall of mice in an effort to observe the spread of cancer (tumour metastasis) which occurs when cells from a primary tumour migrate to other parts of the body where they may come together to form secondary tumours. This mechanism of this is not greatly understood as it is not easy to observe the movement of the cells inside the body, which is precisely what this experiment sought to overcome. The ‘porthole’ enabled the researchers to view the internal organs, including the kidneys and small intestine. Individual tumour cells marked with fluorescent dye were then able to be tracked over the course of two weeks. They observed that the tumour cells appeared to move randomly about the local area before they ended at their final destination – a possibility that they had not previously considered.
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