When combined, their individual contributions led to not only the discovery of the molecular and cellular bases of acute promyelocytic leukaemia (APL), but also a pioneering, synergistic targeted therapy. These advances have transformed what was once one of the most aggressive and deadly forms of cancer into one of the most curable.
APL is a subtype of acute myeloid leukaemia (AML). This aggressive form of blood cancer is caused by a chromosomal rearrangement that results in the fusion of the promyelocytic leukaemia (PML), a stress-response gene which inhibits cancer development, and the retinoic acid receptor alpha (RARA) gene. This abnormality produces the PML-RARA hybrid protein, which blocks blood cell development and leads to a life-threatening accumulation of immature cells.
Thanks to the discoveries by Dejean, de The, Chen and their collaborators, APL can now be treated effectively using retinoic acid, a vitamin A derivative, and arsenic trioxide, which destroys the abnormal hybrid protein and restores normal blood cell development. The 10-year survival rate for patients undergoing targeted therapy has increased to more than 90 per cent.

Dejean’s interest in molecular biology came from her childhood love of nature, sparked by long Sunday walks with her family in the forests near their home in western France and close observation of the beetles, ferns and mosses found along the way.
“From that point on, I knew I wanted to understand how living cells and organisms function,” she says.
Her parents instilled in her a spirit of freedom and critical thinking – two qualities she believes are essential for any future scientist – while her research was driven by a desire to lay bare the mechanisms responsible for the development of cancer cells and how a normal cell becomes diseased.
Dejean began her scientific research career studying the connection between the hepatitis B virus and liver cancer. An unexpected discovery of the genes for the retinoic acid receptor and its mutation in a liver cancer patient provided her team with the first evidence of its involvement in other types of cancer.
Together with de The, they found that the RARA gene is fused to one from another chromosome, the PML gene, to induce the molecular defect that causes APL. The PML-RARA hybrid protein disrupts the formation of membrane-less structures in the cell nucleus, called PML bodies. But administering a type of retinoic acid can restore the integrity of the PML bodies.
“Early on, if we couldn’t master an approach or technique, I initiated collaboration with a specialist in the field,” Dejean says. “Strictly speaking, my journey with APL took 18 years because every problem solved opens up new clues and challenges. The discovery of the retinoic acid receptor gene was serendipitous and marked the beginning of the whole story, but progress generally happens step by step.”
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