TFAP2E Expression Is Associated with Survival and a Transcriptomic Pattern in Ovarian Serous Carcinoma, Supported by Hallmark and Protein-Level Characterization

Background/Objectives: AP-2 transcription factors are increasingly recognized as key regulators in cancer biology. The TFAP2E gene, which encodes the AP-2ε transcription factor, remains understudied in cancer compared with other AP-2 family members. The scarcity of studies examining potential AP-2ε targets and related genes limits our understanding of its functional significance. Moreover, related studies have not incorporated a screening step to select the tumor type for justified molecular investigation. Through comparison of tumor–normal expression differences in a pan-cancer spectrum, this study prioritized ovarian serous carcinoma for downstream assessment. Methods: Expression patterns were evaluated using GENT2, GEPIA2, and TNMplot. After prioritizing ovarian serous carcinoma, TFAP2E and related signatures in TCGA-OV were analyzed using transcriptomic and clinical data from GDC and CDR, followed by comparison of findings with the GSE32062 cohort. The workflow included survival and clinicopathological analyses, outcome-independent limma-voom differential expression analysis and WGCNA, MCODE clustering, gene ontology, immune subtype and stemness assessment, PCA, CancerHallmarks enrichment, clinically adjusted Cox and competing-risk survival modeling, and HPA-derived immunostaining evaluation. Additional analyses assessed WGCNA parameter stability and preservation in GSE32062, an outcome-independent MAD-based variability screen, AP-2 family coexpression, and promoter motif enrichment. Results: TFAP2E was downregulated in ovarian cancer across the three queried resources, whereas higher expression was associated with favorable survival across multiple endpoints. Differential expression and WGCNA identified a TFAP2E-associated signature; its ontology indicated GPCR, stimulus responsiveness, and KRAS enrichment for the 933-gene module. The WGCNA pink module was stable across alternative settings, moderately preserved in GSE32062 (Zsummary = 7.86), and enriched in the outcome-independent MAD screening. GSE32062 supported concordant gene expression patterns and showed an association of TFAP2E with progression-free survival. Exploratory immune analyses showed a modestly increased proportion of C5 tumors in the higher-expression groups, whereas differences in stemness were statistically insignificant. The TFAP2E group associations with PFI and DSS in TCGA-OV and with PFS in GSE32062 remained significant after clinical adjustment; Fine-Gray sensitivity analyses gave consistent results for DSS. Immunohistochemistry provided protein-level characterization; eighteen entries differed between representative normal and tumor specimens, with lower tumor staining in fifteen. The seven-gene candidate set showed a clinically adjusted DSS association in TCGA-OV, which was not supported in the GSE32062 evaluation model. Conclusions: TFAP2E expression is associated with survival and a transcriptomic cross-cohort pattern in ovarian serous carcinoma. Covariate-adjusted and competing-risk analyses supported the association but did not establish clinical utility. The highlighted genes remain exploratory candidates for mechanistic investigation.