Visualization of immune infiltrates in biopsy material and study design. A: Visualization of immune infiltrates and tumor cells by immunohistochemical double-stain for CD8 (upper panel) or CD45RO (lower panel) and pancytokeratin in biopsy material (overview x 50, inset x 300). Stromal infiltrates are indicated by *, arrows indicate intraepithelial CD8+ or CD45RO+ T-cells. B: Study Design. 346 CRC patients were entered into the study, 185 of which had matched biopsies. Histopathological features and clinical data were re-reviewed. Immunohistochemistry for pancytokeratin and CD8 or CD45RO was performed. CD8+ and CD45RO+ T-cell infiltrates in biopsy specimens were evaluated in five HPF each of stroma and neoplastic epithelium. T-cell infiltrates were analysed for prediction of patient survival and histopathologic features of the matched resection specimen.