Molecular mechanisms and classification of castration-resistant prostate cancer: Insights into androgen receptor, cancer stem cells, and neuroendocrine features.

Castration-resistant prostate cancer (CRPC) is a considerable clinical challenge, driven by complex molecular mechanisms that enable tumors to evade androgen deprivation therapy. This review explores the molecular mechanisms driving CRPC progression, focusing on androgen receptor (AR) signaling, cancer stem cells (CSCs), and neuroendocrine differentiation (NED). In AR-dependent CRPC, AR signaling remains pivotal in disease progression. Mutations, splice variants, alternative pathways, and transcriptional regulation facilitate sustained AR activation despite androgen deprivation therapy. In addition, CSCs promote tumor recurrence and treatment resistance by maintaining cellular heterogeneity and evading conventional therapies. Furthermore, castration-resistant neuroendocrine prostate cancer, an aggressive subtype of CRPC, is characterized by AR independence and NED, making treatment challenging. These findings underscore the need for therapeutic strategies targeting AR-, CSC-, and NED-specific mechanisms. Crucially, the molecular classification of CRPC into AR-dependent CRPC, stem cell-like CRPC, and castration-resistant neuroendocrine prostate cancer subtypes-based on the interplay between AR signaling, CSCs, and neuroendocrine features-is essential for advancing precision medicine. Tailoring treatments to the molecular subtype and characteristics of each patient offers the potential to substantially improve prognosis and survival in CRPC.