1. A computer-implemented method of whole tissue classification steps of: training a region of interest (ROI) classifier in a supervised manner wherein labels are given only at a tissue level, the training using a multiple-instance learning variant of backpropagation; training a tissue classifier that uses the output of the ROI classifier; for a given tissue; extracting ROIs and applying the ROI classifier to each ROI thereby obtaining a set of probabilities; providing the probabilities to a tissue classifier; and outputting a diagnosis of the whole-tissue.