Purpose: Chemokines influence both tumor progression and anti-tumor immune response. A 32-bp-deletion polymorphism in the chemokine receptor 5 gene (CCR5Delta32) has been shown to result in a non-functional protein. This study was aimed at evaluating the potential impact of this gene polymorphism on disease progression and treatment outcome in patients with melanoma.
Patients and methods: CCR5 genotyping was performed by PCR on DNA extracted from serum samples of 782 cutaneous melanoma patients with known disease history and long-term clinical follow-up. Genotypes were correlated with patient survival and types of treatment.
Results: Of 782 melanoma patients, 90 (11.5%) were heterozygous and 12 (1.5%) were homozygous for CCR5Delta32. Analyzing the complete cohort, the disease-specific survival from date of primary diagnosis was not influenced by CCR5 status. Similarly, no significant impact could be detected on the treatment outcome of stage III patients. In 139 stage IV patients receiving immunotherapy, CCR5Delta32 was associated with a decreased survival compared to patients not carrying the deletion (median 12.5 vs. 20.3 months, P = 0.029). Multivariate analysis revealed the CCR5 genotype as an independent factor impacting disease-specific survival in this patient population (P = 0.002), followed by gender (P = 0.019) and pathological classification of the primary (pT; P = 0.022).
Conclusion: The presence of the CCR5Delta32 polymorphism in patients with stage IV melanoma results in a decreased survival following immunotherapy and may help to select patients less likely to benefit from this type of treatment.