Objective: To analyze the association between the IRF5 gene variants rs3807135, rs3757385, and rs3778754 and mRNA expression levels in patients from western Mexico diagnosed with melanoma. Methods: An analytical cross-sectional study was conducted including 374 individuals (153 patients with newly diagnosed melanoma and no previous treatment, and 221 controls). The melanoma group was matched to the reference group. Genotyping of the rs3807135 (T>C), rs3757385 (T>G), and rs3778754 (C>G) variants was performed using the allelic discrimination method with TaqMan® probes. Relative mRNA expression was quantified by qPCR using the 2–ΔΔCT method, comparing IRF5 expression levels with those of the housekeeping gene GAPDH. Statistical analyses were performed in R, and allelic and genotypic frequencies were compared between patients and controls using the Chi-square test. Results: No statistically significant associations were identified between IRF5 SNVs rs3807135, rs3757385, and rs3778754 and melanoma risk. The haplotypic pattern comprised TTC, CGG, and CGC, with CGG showing a non-significant protective tendency. The mean relative expression of IRF5 was lower in melanoma patients compared with controls (≈0.39 vs. 1.0; Δ = 0.61), although this difference did not reach statistical significance (U = 1725; p = 0.841). These findings suggest a modest modulatory effect of IRF5 at the haplotypic level, likely driven by combined variant effects. Conclusions: In conclusion, the present study did not identify statistically significant associations between the IRF5 single-nucleotide variants rs3807135, rs3757385, and rs3778754 and melanoma risk in the analyzed population from western Mexico. Likewise, no significant differences in allele or genotype distributions were observed between melanoma patients and control individuals. These findings suggest that the evaluated IRF5 genetic variants do not constitute major susceptibility factors for melanoma in this cohort.
Tapia-Leyva et al. (Tue,) studied this question.