KLK3 and prostate cancer: Hence, we can conclude that the flow cytometry features: CD8+CD45RA−CD27−CD28− (CD8+ Effector Memory cells); CD4+CD45RA−CD27−CD28− (CD4+ Effector Memory Cells); CD4+CD45RA+CD27−CD28− (CD4+ Terminally Differentiated Effector Memory Cells re-expressing CD45RA); CD3−CD19+ (B cells); CD3+CD56+CD8+CD4+ (NKT cells) can be considered as an immunophenotyping profile which predicts the presence of prostate cancer in men with Prostate-Specific Antigen (PSA) levels below 20 ng ml−1.