CD8A and colorectal carcinoma: A strong correlation in the percentile rank of these biomarkers in both areas was observed; therefore, a score based on central tumour expression alone following the immunohistochemical quantification of CD3- and CD8-expressing cell density was considered sufficient for use in the other sample cohorts (Grampian CRC and S:CORT FOCUS) to classify patients (R2 = 0.89, P < 0.0001; Supplementary Fig. S2F).