Background <p>The family with sequence similarity 110 member A (FAM110A) is implicated in cell cycle regulation, but its role in colon adenocarcinoma (COAD) remains unknown. Through integrative bioinformatics analysis, clinical tissue sample validation, and experimental validation, we investigated the role of FAM110A in COAD.</p> Methods <p>We employed a comprehensive bioinformatics approach, utilizing The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets, alongside various R packages for data acquisition and analysis. The clinical COAD tissue samples and their corresponding paracancerous normal colonic mucosa samples were collected for immunohistochemical (IHC) staining to verify the expression of FAM110A in clinical specimens. After knocking down FAM110A, the cell viability, migration, invasion, cell cycle, apoptosis, reactive oxygen species (ROS), malondialdehyde (MDA), 4-hydroxynonenoic acid (4-HNE), Fe²⁺, and glutathione (GSH) levels, and FAM110A, glutathione peroxidase 4 (GPX4), solute carrier family 7 member 11 (SLC7A11), nuclear transcription factor erythroid 2-related factor 2 (Nrf2), and heme oxygenase 1 (HO-1) protein expression levels of HCT-116 and SW620 cells were determined. Furthermore, rescue experiments were performed by overexpressing Nrf2 in FAM110A-knockdown HCT-116 cells to verify the regulatory relationship between Nrf2 and FAM110A in cell growth and ferroptosis.</p> Results <p>Multiple differentially expressed genes in COAD in the TCGA-COAD and GSE20916 datasets were identified. The elevated expression of FAM110A in tumor samples compared to normal tissues suggested its potential diagnostic role in COAD. Multivariate Cox regression models incorporating clinical variables indicated that FAM110A was one of the independent prognostic factors for COAD. The drug sensitivity analysis revealed correlations between FAM110A and the efficacy of several anticancer drugs. Clinical tissue IHC analysis further confirmed the significantly higher expression of FAM110A in COAD tumor tissues compared with paired paracancerous normal colonic mucosa tissues. The immune infiltration analysis revealed that FAM110A could serve as a biomarker for predicting response to immunotherapies for COAD. FAM110A was enriched in multiple pathways. Knocking down FAM110A reduced cell viability, migration, invasion, and GSH levels, as well as GPX4, SLC7A11, Nrf2, and HO-1 protein expression levels, arrested the cell cycle, and elevated apoptosis, ROS, MDA, 4-HNE, and Fe²⁺ levels in HCT-116 and SW620 cells. Overexpression of Nrf2 reversed the effects of FAM110A knockdown on HCT-116 cell growth and ferroptosis.</p> Conclusions <p>Our findings underscore the diagnostic and prognostic significance of FAM110A in COAD. Knocking down FAM110A alleviated COAD via Nrf2/HO-1 axis inhibition to promote ferroptosis, and Nrf2 overexpression could rescue the ferroptosis and growth inhibition induced by FAM110A deficiency, providing a theoretical basis for developing drugs targeting FAM110A for treating COAD.</p>