In this talk we summarize our work on NLO QCD corrections to the amplitude for double-Higgs boson production in the gluon fusion channel. We describe our setup to reduce the Feynman integrals of the amplitude to a minimal set of master integrals, and how we compute them. Finally we remark on how so-called uniformly transcendental integrals can be identified in the context of expansion by regions, which we have used extensively in our computation of boundary conditions for systems of differential equations for the master integrals.