Genetic susceptibility to keloid disease and hypertrophic scarring: Transforming growth factor β1 common polymorphisms and plasma levels

Keloid disease and hypertrophic scars are dermal tumors that are often familial and typically occur in certain races. Their exact etiology is still unknown. Transforming growth factor β1 (TGF-β1) plays a central role in wound healing and fibrosis and has been implicated in the pathogenesis of keloid disease and hypertrophic scar. The aims of this study were to measure the plasma level of TGF-β1 in patients compared with controls, and to investigate the association of five common single nucleotide polymorphisms in TGF-β1 with the risk of keloid disease and hypertrophic scar formation. Platelet-poor plasma levels of TGF-β1 in 60 patients (15 with hypertrophic scar and 45 with keloid disease) and 18 controls were measured using an enzyme-linked immunoabsorbent assay technique. A polymerase chain reaction-restriction fragment length polymorphism method was used for genotyping TGF-β1 polymorphisms. DNA samples from 133 patients (101 with keloid disease and 32 with hypertrophic scar) and 200 controls were examined. All patients and controls were Caucasians of Northern European extraction. There was no statistically significant difference in TGF-β1 plasma levels between patients with keloid disease and hypertrophic scar and controls. There was also no statistically significant difference in genotype or allele frequency distributions between patients and controls for codons 10, 25, and 263 and for -509 and -800 single nucleotide polymorphisms of the TGF-β1 gene. These results suggest that TGF-β1 plasma levels and common polymorphisms are not associated with a risk of keloid disease and hypertrophic scar formation. This lack of association may be significant in view of the importance attached to the role of TGF-β1 in dermal scarring. To the authors' knowledge, this is the first report of a case-control association study in keloid disease and hypertrophic scars using any single nucleotide polymorphisms.