Neurofibromin 1 (NF1) is a tumor suppressor gene frequently altered across diverse cancer types, yet its biological significance in ovarian cancer remains incompletely characterized. Here, we integrated cohort‐scale somatic mutation profiling with functional validation to characterize the mutational and cellular consequences of NF1 loss in ovarian cancer. Somatic mutation data from the TCGA ovarian cancer cohort were analyzed to define NF1‐associated mutation types, tumor mutational burden, mutational signatures, and co‐occurring alterations in DNA damage repair (DDR) pathways, together with pathway‐ and gene set–level functional enrichment analyses. NF1 alterations were predominantly truncating and consistent with loss‐of‐function events. NF1‐mutant tumors did not exhibit increased global tumor mutational burden or uniform APOBEC hypermutation but showed distinct single‐nucleotide substitution patterns and frequent comutations in core DDR‐related genes. Functional enrichment analyses further highlighted coordinated involvement of pathways related to DNA replication, RNA processing, and proteostasis. Clinically, NF1 mutation was not independently associated with overall survival. Stable NF1 knockdown ovarian cancer models showed that NF1 depletion did not affect basal proliferation but increased sensitivity to hydroxyurea‐induced replication stress, accompanied by increased γ H2AX accumulation. Together, these findings indicate that NF1 loss defines a DNA damage–associated mutational and cellular state in ovarian cancer. Rather than acting as a direct prognostic determinant, NF1 mutation appears to increase vulnerability to replication stress and DNA damage, providing functional insight into its role in ovarian tumor biology.
He et al. (2026) studied this question.