PTEN as a Biomarker: Background and Clinical Significance

Biomarker-driven management is reshaping prostate cancer care, and PTEN has emerged as one of the most clinically relevant molecular alterations across the disease continuum. In this discussion, Gordon A. Brown, DO, FACOS, an associate professor at Rowan University School of Osteopathic Medicine, program director of Urologic Surgery at Rowan University School of Osteopathic Medicine, and director of New Jersey Urology’s Center for Advanced Therapeutics, explains that PTEN is a tumor suppressor gene that regulates the PI3K/AKT/mTOR signaling pathway, functioning as a critical brake on cellular proliferation. Loss of PTEN activity removes this regulatory control, promoting unchecked tumor growth and survival signaling that contributes to disease progression.

Brown notes that PTEN alterations carry both prognostic and predictive significance. PTEN abnormalities are identified in approximately 20% to 25% of aggressive localized prostate cancers and increase in prevalence to nearly 50% to 60% in advanced and castration-resistant disease. Clinically, PTEN deficiency correlates with higher-grade tumors, increased risk of biochemical recurrence following definitive therapy, and inferior treatment outcomes, underscoring its role as a marker of aggressive disease biology.

Importantly, Brown distinguishes PTEN loss at the genomic level from PTEN deficiency at the protein expression level, emphasizing that protein deficiency assessed by immunohistochemistry provides stronger clinical relevance. PTEN deficiency enables activation of the AKT pathway, allowing tumor cells to bypass androgen receptor suppression and evade apoptosis, thereby establishing the biologic rationale for combining androgen-directed therapy with AKT inhibition in metastatic hormone-sensitive prostate cancer.