Analysis of intratumoural TMA cores (taken from the tumour centre) from the QUASAR2 cohort revealed similar numbers of infiltrating CD8+ and CD3+ cells per mm2 to those reported in previous reports15 (Table S4), and a highly statistically significant correlation between the densities (defined as the proportion of positive cells to total cell nuclei) of both markers (Spearman rho 0.65; P = 2.2 × 10−16). Here, CD8A is linked to neoplasm.