CD8A and neoplasm: 20 This improvement of T-cell response against the tumours with a reduction of PD-L1 and vascular endothelial growth factor (VEGF) expression is an example of inducing a 'hot' tumour when compared to the lack of immune infiltration in 'cold' breast tumours or the controls in this experiment. 21 The quantity of tumour infiltrating lymphocytes is considered to be a good predictive biomarker of therapy responses, where intratumoral CD8+ is considered to have a better prognosis. The hotter the tumour, the more tumour infiltrating lymphocytes present. 22