Fig. 4

Errors of automated PHH3/MART1 image analysis in five different melanomas. a Three PHH3-positive non-melanocytic cells (possibly lymphocytes) that overlay or are in close connection to MART1. b They are thus falsely counted as PHH3/MART1-positive cells. c Brown pigment embedded in or in close connection to MART1. d False-positive counts consequently occur. e Very pale MART1 stain of melanocytic cells. f A PHH3-positive mitosis is thus overlooked. g Very dark MART1 stain or artifact that resembles pixel intensities of brown staining. h Because shape, in addition, resembles a nucleus, a false-positive count is made. i Telophase of PHH3/MART1-positive cell. j Distance between chromatin of dividing nucleus is too large to fuse them into one object with the post-processing step dilation, and this mitosis is therefore overlooked