Mechanistically, Ager<sup>mKO</sup> muscles resist cancer-induced atrophy by maintaining an active Akt-GSK-3β-PGC-1α pathway, and increasing the synthesis of myosin heavy chain (MyHC)-I and -IIa (71.8% [p = 0.008] and 73.9% [p = 0.002] increase, respectively) along with a 76.3% (p = 0.008) increase in hybrid MyHC-I/IIa myofibres. The gene discussed is GSK3B; the disease is cancer.