In the review “A role for T-lymphocytes in human breast cancer and in canine mammary tumours”, the authors compare tumour T-lymphocyte infiltration and the CD4+/CD8+ T-cell ratio with low survival rates, the action of Th2 cells in the acceleration of tumour progression and a poor prognosis with the presence of large numbers of Treg cells [39]. Here, CD8A is linked to breast cancer.