Previous results indicate that the CD8+ cell density in the IM correlates with a favourable clinical outcome in CRC (40), whereas the opposite conclusion was reached for breast cancer (41); however, currently, it is not known whether the opposite predictive direction is due to migratory processes induced by locally secreted factors or architectural barriers capturing these cells in the tumour compartments or because functional CD8+ T cells account for only a small portion of the total CD8+ T cell population. The gene discussed is CD8A; the disease is breast cancer.