1. A medical image analysis method for identifying biomarker-positive tumor cells, the method comprising: reading a first digital image and a second digital image into memory, the first and second digital image depicting the same area of a first slide, the first slide comprising multiple tumor cells having being stained with a first stain and with a second stain, the first stain selectively staining nuclei, the second stain selectively staining a particular biomarker, at least one of presence and amount of the biomarker in a tumor cell being indicative of a tumor cell belonging to a particular cancer-subtype, the light intensity values of the first digital image correlating with the amount of the first stain in the tumor cells, and the light intensity values of the second digital image correlating with the amount of the second stain in the tumor cells; identifying a plurality of nuclei and positional information of said nuclei by analyzing the light intensities in the first digital image; identifying cell membranes which comprise the biomarker by analyzing the light intensities in the second digital image and by analyzing the positional information of the identified nuclei; and identifying biomarker-positive tumor cells in said area, wherein a biomarker-positive tumor cell is a combination of one identified nucleus and one identified cell membrane that surrounds the identified nucleus.