Analysis of the relationship between gene expression and outcome in the validation set of patients. Immunohistochemical analysis of the expression of 8 selected genes in the validation series of patients using TMAs. The patients were grouped into quartiles according to the protein expression level of each marker, and the DSS of the fourth quartile (the one with the highest expression) was compared with that of the rest of the series (quartiles 1 to 3). For each marker, a representative field of a stained tissue section and the Kaplan-Meier curves are shown. Note ALDH1A1 and STAT1 immunostaining, restricted mainly to macrophages; SH2D1A immunostaining mainly in T cells; and TOP2A, RRM2, PCNA, MAD2L1, and CDC2 overexpression in the neoplastic H/RS cells. Micrographic images were obtained with a BLISS Slide Scanner (Bacus Laboratories) equipped with a Zeiss Axioplan 2 microscope (Zeiss, Oberkochen, Germany). A 40 ×/0.75 objective lens was used to visualize images, which were acquired through software provided with the BLISS scanner.