OR51A4 is an olfactory receptor family member located on chromosome 11 with primary odorant receptor activity at the plasma membrane. While its canonical function relates to olfactory signaling, OR51A4 has emerged as a potential biomarker in cancer-related research. In prostate cancer, OR51A4 was identified as hypomethylated in aggressive tumors compared to indolent tumors in a cohort of Hispanic/Latino men, suggesting altered epigenetic regulation may associate with disease aggressiveness 1. In cholangiocarcinoma, OR51A4 was identified as a differentially expressed gene in a homologous recombination deficiency-based prognostic model, positioning it among six candidate biomarkers for cancer prognosis prediction 2. Additionally, OR51A4 expression was significantly upregulated (>2-fold) following weight restoration in anorexia nervosa patients, indicating transcriptional changes associated with metabolic recovery 3. OR51A4 was also found hypomethylated in small-for-gestational-age newborns treated with growth hormone, though the clinical significance of this methylation change remains unclear 4. These findings suggest OR51A4 may have broader regulatory roles beyond olfaction, though its mechanistic involvement in cancer biology and metabolic processes requires further investigation.