Screening and identification of novel candidate biomarkers of focal cortical dysplasia type II via bioinformatics analysis.

Purpose: Focal cortical dysplasia (FCD) is the most common developmental malformation that causes refractory epilepsy. FCD II is a common neuropathological finding in tissues resected therapeutically from patients with drug-resistant epilepsy. However, its molecular genetic etiology remains unclear. This study aimed to identify potential molecular markers of FCD II using bioinformatics analysis.

Methods: We downloaded two datasets for FCD II from the Gene Expression Omnibus data repository. Differentially expressed genes (DEGs) between FCD II and normal brain tissues were identified, and functional enrichment analysis was performed. A protein-protein interaction network was constructed, and hub genes were identified from the DEGs. The hub gene expression was validated using WB in vitro. IHC staining was performed to verify the feasibility of the target molecular markers identified in the bioinformatics analysis.

Results: One hundred sixty-seven common DEGs were identified between the datasets. The GO and KEGG analyses showed that variations were prominently enriched in some functions associated with gene expression. Five hub genes (i.e., FANCI, FANCA, BRCA2, RAD18, and KEAP1) were identified. Western blotting confirmed that all hub gene expressions were higher in the FCD II tissue than in the normal brain tissue. IHC staining showed that the FANCI expression significantly increased in the FCD II tissue.

Conclusion: There are DEGs between FCD II and normal brain tissues, which may be considered biomarkers for FCD II, along with FANCI. The DEGs and hub genes identified in the bioinformatics analysis could serve as candidate targets for diagnosing and treating FCD II.