In this paper, we view the problem of receive beamforming in uplink cascade multiple-input multiple-output (MIMO) systems as an instance of that of cascade multiterminal source coding for lossy function computation. Using this connection, we establish two coding schemes for the second and show that their application leads to efficient beamforming schemes for the first. In the first coding scheme, each terminal in the cascade sends a description of the source that it observes; the decoder reconstructs all sources, lossily, and then computes an estimate of the desired function. This scheme improves upon standard routing in that every terminal only compresses the innovation of its source w.r.t. the descriptions that are sent by the previous terminals in the cascade (i.e., conditional rate distortion). In the second scheme, the desired function is computed gradually in the cascade network, and each terminal sends a finer description of it. In the context of uplink cascade MIMO systems, the application of these two schemes leads to efficient centralized receive-beamforming and distributed receive-beamforming, respectively.