Upregulation of RPLP1 in PBMCs as a screening biomarker for melanoma

Early detection of melanoma is essential for improving patient outcomes. This research aimed to identify upregulated gene expression in peripheral blood mononuclear cells (PBMCs) induced by secretory factors derived from melanoma cells. These gene alterations may serve as potential non-invasive biomarkers for melanoma detection. Melanoma gene expression profiles from NCBI database were analyzed using the bioinformatics tool (CU-DREAM). A total of 85 participants were enrolled in the study. Expression levels of seven candidate genes were evaluated in a coculture model using PBMCs from healthy participants (n = 5) and melanoma cell lines at 24, 48, and 72 hours by quantitative real-time polymerase chain reaction (qRT-PCR). Based on these findings, the upregulated gene was further examined in PBMC samples for clinical expression analysis, including melanoma patients (n = 15), patients with various cancer types (n = 35), and healthy controls (n = 30). Receiver operating characteristic (ROC) curve analysis was carried out to determine the diagnostic performance of the candidate gene. Among the seven candidate genes, RPLP1 mRNA expression showed statistically significant upregulation in PBMCs cocultured with both melanoma cell lines, A375 (p = 0.0328) and SK-MEL-28 (p = 0.0311), at 24 hours compared with PBMC controls. The RPLP1 expression in PBMC blood samples also showed upregulation in melanoma patients compared to healthy controls (p = 0.0006). RPLP1 upregulation demonstrated good discriminative performance in this cohort with 93.30% sensitivity, 70.00% specificity, and an area under the curve (AUC) of 0.813 (p < 0.0001). RPLP1 upregulation in PBMCs may reflect a cancer-associated signal with relative enrichment in melanoma. Although elevated expression was also observed in breast cancer PBMCs, RPLP1 may still have potential as a minimally invasive and cost-effective screening biomarker for melanoma, given its high sensitivity in this study cohort. Further validation in larger, independent cohorts is required before clinical application.