Mutation status and tumour gene expression-based classification methods only have a moderate predictive accuracy and limited clinical usefulness for predicting the risk of recurrence.12–14 Recently, many reports have demonstrated the favourable prognostic impact of in situ immune cell infiltration in tumours.15–17 Tumour-infiltrating lymphocytes (TILs), especially CD3 + and CD8 + T cells,17,18 may act as indicators of the host immune response to the tumour, and may represent a strong independent positive predictor of relapse and overall survival. This evidence concerns the gene CD8A and neoplasm.