Size Does Matter: Telomere Length and Melanoma Risk

Hensin Tsao, MD, PhD

SNPs in genes associated with telomere length were frequently found in patients with melanoma, but longer was not better.

Alterations in genes affecting telomere function have been shown to be associated with melanoma development. Telomeres are affected by age and by exposure to environmental factors that also promote cancer growth. Longer telomeres have been associated with melanoma. To determine whether this association is explained by shared genetic variants, shared environmental effects, or by the effects of cancer on telomere length, investigators conducted a large case-control comparison in 11,108 melanoma patients and 13,933 controls. They compared the groups for presence of seven single nucleotide polymorphisms (SNPs) previously associated with mean leukocyte telomere length.

Four SNPs, in genes TERC, TERT, OBFC1, and RTEL1, were significantly more common in the melanoma patients than in controls. The SNPs were located near SNPs associated with melanoma risk. A score calculated by these researchers to predict telomere length based on the presence of the studied SNPs linearly predicted melanoma risk: As the score rose, so did melanoma risk. The authors conclude that “the genetic factors underlying telomere length have an especially strong influence on melanoma risk” and note the unusual association of longer telomere length and predisposition to melanoma. They propose that longer duration of cell proliferation is made possible by longer telomeres, increasing the opportunity for mutations to develop.

Citation(s):

Iles MM et al. The effect on melanoma risk of genes previously associated with telomere length. J Natl Cancer Inst 2014 Sep 17; [e-pub ahead of print].