Hypoxia-Inducible Factor-1α Gene (HIF1A) rs11549465 (1772 C>T) Polymorphism, Body Mass Index, Smoking, and Cutaneous Melanoma: An Observational Case–Control Study

Background: Hypoxia and oxidative stress are central features of cutaneous melanoma biology. Body mass index (BMI) and smoking, both of which can influence systemic hypoxia, inflammation, and oxidative stress, have shown inconsistent associations with melanoma. We investigated the association of the hypoxia-inducible factor-1 alpha gene (HIF1A) rs11549465 (1772 C>T; Pro582Ser) polymorphism, alone and in combination with overweight/obesity or smoking habits, with cutaneous melanoma susceptibility and clinicopathological characteristics. Methods: This observational case–control study included 132 Caucasian Italian patients with cutaneous melanoma and 312 healthy controls. The rs11549465 polymorphism was genotyped by genomic DNA restriction fragment analysis. Logistic regression provided age- and sex-adjusted and mutually adjusted estimates. Results: Genotype and allele frequencies did not differ between patients and controls. Within the melanoma cohort, smoking for ≥20 years remained associated with metastatic disease after adjustment for BMI ≥ 25 kg/m2, age at diagnosis, and sex (aOR = 3.12, p = 0.006), whereas BMI did not (aOR = 1.23, p = 0.612). Compared with healthy controls, metastatic melanoma was independently associated with BMI ≥ 25 kg/m2 (aOR = 2.26, p = 0.010) and smoking for ≥20 years (aOR = 3.85, p < 0.001). Mean pack-years were higher in melanoma patients than controls (9.4 ± 16.7 vs. 5.1 ± 12.2; p = 0.002), and ≥10 and ≥20 pack-years remained associated after age- and sex-adjustment (aOR = 2.19, p = 0.001 and aOR = 3.31, p < 0.001, respectively). Mean pack-years were higher in MetM than NMetM (13.1 ± 21.0 vs. 5.9 ± 10.0; p = 0.013), and ≥20 pack-years was associated with MetM (OR = 3.05, p = 0.017). Adjusted associations with head/neck melanoma (n = 13) were observed for CC plus BMI ≥ 30 kg/m2 (aOR = 9.07, p < 0.001), ≥20 cigarette/day (aOR = 5.96, p = 0.004), ≥20 years smoking (aOR = 6.64, p = 0.003), and other smoking measures. Conclusions: To our knowledge, this is the first report on the interplay between the rs11549465 polymorphism and cutaneous melanoma. HIF1A rs11549465 was not independently associated with melanoma susceptibility. Associations involving smoking, BMI, joint genotype–lifestyle exposures, and anatomical localization had wide confidence intervals and were exploratory; small subgroups and multiple comparisons require cautious interpretation and independent validation.