This transition was believed to be associated with RhoA signaling, and this transition tremendously reduced Rac1 activity.225 Moreover, cancer cells could dynamically and alternately adapt their metabolism to confinement and non-confinement during their collective migration process.226,227 Collectively, the pore size of hydrogel scaffold is an important indicator or hallmarker for cell biology and fate, and more attention needs to be paid when preparing hydrogel scaffolds objective to some certain application. The gene discussed is RAC1; the disease is cancer.