RCBTB2 in cancer: context-dependent functions and translational boundaries.

RCBTB2 (RCC1 and BTB domain-containing protein 2), located at chromosome 13q14, is affected by deletion, amplification, expression change, or gene fusion across the cancers studied to date. The divergent directions of these alterations do not fit a tumor-suppressor model with a fixed direction of action. Here, genetic, transcriptomic, protein-level, and functional evidence is integrated across reported cancer contexts and interpreted through three layers: the genomic neighbourhood, cell lineage, and signalling or cellular state. Within this model, the 13q14 neighbourhood determines whether RCBTB2 is altered independently or alongside genes such as RB1. Its functional consequences are further constrained by lineage-specific networks and may vary with proteostatic and ciliary states. Direct evidence connects RCBTB2 with GPAA1-related proteostasis in prostate cancer and primary ciliogenesis in mammalian cells. The proposed link between altered ciliogenesis and Hedgehog signalling in SHH medulloblastoma, however, has not been tested. On current evidence, RCBTB2 merits evaluation as a context-dependent classification or prognostic candidate, not as a broadly applicable therapeutic target. Resolving gene-specific effects within 13q14, testing cross-lineage interactions, and measuring incremental clinical value in independent cohorts are therefore the immediate priorities.