1. An information processing apparatus comprising: an input unit that inputs a plurality of first regions selected with first priority order as diagnosis targets from a tissue sample image obtained by capturing a tissue, a plurality of second regions selected with second priority order as diagnosis targets from the tissue sample image, and pieces of position information of the respective regions selected on the tissue sample image; and a calculator that calculates a similarity between the plurality of first regions with the first priority order and the plurality of second regions with the second priority order, based on correlations considering distances between the selected regions on the tissue sample image; wherein one or more of the input unit and the calculator are implemented via a CPU.