
The latest hope for stopping untreatable cancers traces its roots to a turn-of-the-century German zoologist, gazing into a microscope at the eggs of sea urchins.
Studying the process of fertilization, Theodor Boveri made a curious observation. In most cases, the correct number of urchin chromosomes lined up in perfect order and created an embryo. But every once in a while, the chromosomes would get scrambled, leading to unpredictable cell division and uncontrollable growth. Those aberrant divisions were the root cause of cancer, Boveri theorized in 1914, a once-controversial claim that has since been cemented in oncologic lore.
That phenomenon, called chromosomal instability, has long been implicated in cancer’s ability to evade modern treatments and spread throughout the body. But only in recent years have researchers begun to disentangle the myriad biological changes that make chromosomes go haywire, and the way cancer uses that chaos to thrive.