Hydrogel implantation induced a mechanical response in the epidermis 1 day after injection, as indicated by an increase in nuclear YES-associated protein 1 (YAP1) and megakaryoblastic leukaemia/myocardin-like 1 (MAL), two modulators of mechanotransduction28 (Fig. 5a,b). The gene discussed is MAL; the disease is leukemia.