Recognising Cancer: Genetic Signs can Appear Decades Before Diagnosis

Cancer is not due to a single genetic mutation, resulting instead from a process of evolution. Starting with just a few chance genetic changes, selective pressure will eventually result in thousands of mutations that contribute to the tumour’s malignancy.

By the time cancer has been diagnosed, many mutations have already occurred, yet a study published in Nature suggests that the earliest mutations occur far earlier than expected. Researchers analysed over 2500 cancers using whole-genome sequencing, and studied the timing of the early driving mutations. Not only did such mutations often precede diagnosis by years, half of the earliest changes also occurred in just 9 genes.

These findings are of interest, as it may be possible in the future to screen for these genetic changes: by examining free DNA in the blood, for example, in order to identify the early seeds of cancer.