Dysregulation of transcription factors is a hallmark of lung tumorigenesis, and Sex-determining region Y-box 9 (SOX9) has emerged as a putative master regulator at the intersection of development and malignancy. Building on evidence from lung and other solid tumors, we summarize how aberrant SOX9 expression, shaped by epigenetic modification, post-translational regulation, and non-coding RNAs, drives proliferation, survival, invasion, and therapy resistance. In lung cancer, SOX9 appears to orchestrate a stem-like, plastic cell state, promoting epithelial-mesenchymal transition (EMT), metastatic dissemination, and remodeling of the tumor microenvironment (TME). These context-dependent functions position SOX9 both as an oncogenic driver and, in selected settings, as a modulator of treatment response. This review integrates current mechanistic and translational data to frame SOX9 as a clinically actionable node within key signaling circuits relevant to non-small cell and small cell lung cancer. We highlight emerging strategies that directly or indirectly target SOX9, including interference with upstream pathways, epigenetic reprogramming, and RNA-based approaches designed to modulate SOX9 expression or activity. Finally, we propose SOX9 as a dual biomarker and therapeutic handle to guide rational combination therapies aimed at overcoming drug resistance and improving patient stratification. By connecting molecular insight with unmet clinical needs, this article outlines a conceptual roadmap for SOX9-centered therapeutic approaches in lung cancer. A key novelty of this review is the integration of SOX9-centered molecular mechanisms with therapeutic resistance, biomarker potential, and emerging indirect targeting strategies in lung cancer, thereby providing a translational framework for future SOX9-guided interventions.
Chen et al. (2026) studied this question.