1. A medical image processor comprising: an input unit to input a cell shape image showing a shape of a cell in a tissue slice and a fluorescent image showing expression of a specific protein in the tissue slice as a fluorescent bright point; an operation unit to specify an analysis target region from the cell shape image; a cell nucleus extracting unit which extracts a region of a cell nucleus from the cell shape image; a fluorescent bright point extracting unit which extracts a fluorescent bright point showing expression of the specific protein from the fluorescent image; a feature amount calculating unit which calculates a feature amount showing an expression amount of the specific protein in the specified analysis target region based on the extracted cell nucleus region in the analysis target region specified with the operation unit and the fluorescent bright point; and an output unit which outputs the calculated feature amount.