Serum and salivary Cu/Zn ratio as a diagnostic biomarker for oral submucosal fibrosis: an analysis of trace metals and LOX gene variants

This study aimed to analyze the serum and salivary levels of copper (Cu), zinc (Zn), iron (Fe), chromium (Cr), manganese (Mn) and the Cu/Zn ratio and investigate the association between LOX gene variants (rs18800449 and rs2288393) and oral submucosal fibrosis (OSMF). A total of 250 subjects were included in the study: OSMF patients (n = 50), areca nut chewers without OSMF (n = 100) and controls (n = 100). Trace metals were measured using an atomic absorption spectrophotometer, while LOX gene variants were genotyped using the tetra primer amplification refractory mutation system (tetra ARMS) polymerase chain reaction (PCR) method. The results showed significant variations in serum and salivary Cu, Zn, Fe and Cr levels and serum Mn concentrations among the three groups (p < 0.0001). Serum Cu levels were significantly higher in OSMF patients, while serum Zn levels were significantly lower. Both serum and salivary Cu/Zn ratios demonstrated a statistically significant difference (p < 0.0001) and diagnostic potential to differentiate OSMF from chewers and controls. However, LOX gene variants did not show an association between OSMF and chewers, except for rs1800449 genotypes, which showed a significant and increased risk with the AA genotype in OSMF patients compared to controls (OR = 7.58; 95%CI 2.30–24.97). The study suggests that trace elements and genetic variants may impact the etiology of OSMF. The findings may aid in early diagnosis, suitable treatment, and as a prognostic indicator for disease progression.