Background: Epidemiological studies have found obesity to be a risk factor for prostate cancer. Our prior independent studies in women have reported a strong relationship between variants of OB (leptin) gene, body mass index, and age at menarche and sporadic breast cancer. The current study investigates an association between genetic variants of the human obesity gene, serum leptin levels, and body mass index in subjects with prostate carcinoma and in age- and gender-matched normal subjects.
Methods: Blood samples from 69 patients with prostate cancer and 137 age-matched control subjects were collected. Serum leptin level was investigated by radioimmunoassay, and body mass index was calculated. Allele sizes were determined via standard polymerase chain reaction. Statistical analysis was performed using SPSS10.0 computer software.
Results: There was a strong association with significantly elevated serum leptin levels, high body mass index, and higher frequency of LEPR longer alleles in patients with prostate cancer than in control subjects. By contrast, a modest but not significant increase in the frequency of LEP short alleles was found in patients with prostate cancer as compared with control subjects. Analysis within groups 1 (low leptin level and low body mass index) and 2 (other) showed a significant association only in group 2, with high frequency of OB gene variants (LEPR long alleles and LEP short alleles) in patients with prostate cancer but not in control subjects.
Conclusions: These results represent the first report of a significant association between specific leptin gene alleles, serum leptin levels, and body mass index in subjects with prostate cancer. Consistent with prior reports, we also report a significantly elevated serum leptin level in patients with prostate cancer, suggesting a strong link with obesity as an increased risk factor.