Interleukin-1β Gene (IL1B) rs1143634 (+3954 C>T) Polymorphism and Cutaneous Melanoma Risk: An Observational Case-Control Study in Northeast Italy.

Background

Immune modulation is central to cutaneous melanoma, and antitumor immune responses may be influenced by host genetic background. This study investigated the association between the interleukin-1β gene (IL1B) exon 5 synonymous single-nucleotide polymorphism rs1143634 (+3954 C>T) and cutaneous melanoma in a Northeast Italian case-control cohort.

Methods

The study included 133 Caucasian patients with cutaneous melanoma and 945 healthy controls from Northeast Italy. The rs1143634 polymorphism was genotyped by PCR-restriction fragment length polymorphism (PCR-RFLP).

Results

Compared with healthy controls, melanoma patients showed higher frequencies of the rs1143634 T allele [27.8% vs. 20.3%; odds ratio (OR) = 1.52, 95% confidence interval (CI) = 1.13-2.03, p = 0.005] and CT genotype (43.6% vs. 31.6%; OR = 1.67, CI = 1.16-2.42, p = 0.006), whereas the CC genotype was less frequent (50.4% vs. 63.9%; OR = 0.57, CI = 0.40-0.83, p = 0.003). TT + CT genotypes were more frequent among non-metastatic melanoma cases than controls (OR = 2.23, CI = 1.37-3.64, p = 0.001), but the direct comparison between metastatic and non-metastatic cases was not statistically significant. Among melanoma patients, TT + CT carriers showed an inverse association with Stage IV disease (OR = 0.38, CI = 0.15-0.94, p = 0.036) and a positive association with upper-limb melanoma (OR = 9.10, CI = 1.11-75.0, p = 0.040); these subgroup findings were exploratory because of small numbers and wide confidence intervals.

Conclusions

These preliminary findings suggest a possible association between IL1B rs1143634 T allele carriage and cutaneous melanoma susceptibility in this cohort. The Stage IV and upper-limb observations should be considered hypothesis-generating. Larger independent studies, correction-aware statistical designs, cytokine or expression measurements, and functional validation are needed to confirm these observations and clarify their biological relevance.