Here, we investigated the presence of a humoral response against highly immunogenic peptides derived from the envelope proteins of HERV-K, HERV-W, and HERV-H in the plasma of patients with PCa, BPH and a borderline cohort, given the easy accessibility of such body fluid and its advantage in using a specific HERV-directed immune response as a possible disease biomarker. The gene discussed is ERVW-1; the disease is benign prostatic hyperplasia.