Cleo received her PhD in Biological Sciences from University College London in 2001. She then spent four years as a MRC Career Development Fellow in the laboratory of Prof. Chris Higgins at the MRC Clinical Sciences Centre (now the London Institute of Medical Sciences), Imperial College London, where she developed a keen interest in cancer biology.

In 2006, she moved to the Blizard Institute to pursue her interest in senescence and cancer, spending four years in the laboratory of Prof. David Beach (FRS). During this time, she established our Phenotypic Screening facility, and has used this technology to discover novel regulators of the ageing and senescence biomarker, p16.