Heavy quark production in high-energy proton-nucleus (pA) collisions is described in the framework of the Color Glass Condensate. kT factorization is broken even at leading order albeit a more general factorization in pA holds at this order in terms of 2, 3 and 4 point correlators of Wilson lines in the nuclear target. The x-evolution of these correlators is computed in the large A and large N mean field limit of the Balitsky-Kovchegov equation. We show results for heavy quark production at RHIC and LHC energies.