PHI, which combines total PSA, free PSA and -2 fraction of the proPSA (p2PSA) from the formula (p2PSA/free PSA)*total √PSA, has higher effectiveness than PSA and the percentage of free PSA in the detection of PCa, with areas under the curve ranging from 0.67 to 0.781 according to the literature [35]. The gene discussed is KLK3; the disease is posterior cortical atrophy.