Leptin is associated with increased prostate cancer risk: a nested case-referent study.

Area of Science:

• Oncology
• Endocrinology
• Epidemiology

Background:

• Western lifestyle factors are implicated in prostate cancer pathogenesis.
• Obesity's role in prostate cancer remains unclear, despite leptin's potential to stimulate prostate growth.
• Leptin receptors are present in the prostate, suggesting a direct biological link.

Purpose of the Study:

• To investigate the association between plasma leptin concentrations and prostate cancer risk.
• To explore the role of leptin and its receptors in prostate cancer development.
• To determine if metabolic variables, hormones, or growth factors modify the leptin-prostate cancer relationship.

Main Methods:

• A case-control study involving 149 men with prostate cancer and 298 matched referents from Northern Sweden.
• Analysis of stored blood samples for leptin, insulin, IGF-I, IGF-I-binding proteins, testosterone, and sex hormone-binding globulin.
• Conditional logistic regression used to estimate relative risks; prostate cancer specimens examined for leptin receptor immunoreactivity.

Main Results:

• Moderately elevated leptin levels were associated with an increased risk of prostate cancer (Relative Risk for quintiles: 1.0, 2.1, 2.6, 1.4, 1.6).
• This association persisted after adjusting for metabolic variables, testosterone, and IGF-I and its binding proteins.
• Leptin receptor immunoreactivity was detected in normal, high-grade prostatic intraepithelial neoplasia, and malignant prostatic epithelium.

Conclusions:

• Moderately elevated plasma leptin concentrations are associated with the later development of prostate cancer.
• Leptin may directly affect prostatic intraepithelial neoplasia or act through indirect mechanisms.
• A critical fat mass, indicated by intermediate leptin levels, appears to create a milieu favorable for prostate cancer development.