Issue: November 2012
October 15, 2012
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Obesity increased risk for prostate cancer progression

Issue: November 2012
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Fat tissue surrounding the prostate of overweight or obese men with prostate cancer reduced immunosurveillance, providing a favorable environment for cancer growth, according to study results.

Periprostatic adipose tissue surrounds the prostate. Prostate tumor cells often infiltrate fatty tissue, which secretes a wide range of growth factors for the cells.

The gene expression profile for periprostatic adipose is unknown. Uncovering the expression profile may reveal the influence of obesity on prostate cancer, according to background information in the study.

Researchers enrolled 18 patients scheduled for retropubic radical prostatectomy or partial open prostatectomy between May and October 2009.

Ricardo Ribeiro, MD, of the Molecular Oncology Group in Portugal, and colleagues divided the participants into three groups: benign prostatic hyperplasia (n=6); organ-confined prostate cancer (n=6) and extraprostatic prostate cancer (n=6).

Researchers placed three patients who were considered lean (BMI <25) and three more considered overweight/obese (BMI ≥25) in each prostatic disease group.

Ribeiro and researchers reviewed patients’ clinicopathological characteristics and serum PSA concentration at diagnosis.

Results of the study indicated that regardless of type of disease, the overweight men had different levels of gene activity in the periprostatic adipose tissue compared with lean men.

Antiapoptotic genes ANGPT1 and HSPB8 were up-regulated in periprostatic adipose tissue of obese/overweight patients, according to the study.

The expression of EIF5A, known to activate the mitochondrial pathway, was repressed in obese/overweight men, study results showed.

Researchers also found an increased expression of genes involved in cell growth and differentiation, including LEP, ANGPT1 and NPY1R.

“Taken together, these anti-lipolytic, adipo/lipogenic, proliferative and anti-apoptotic effects in the [periprostatic] adipose tissue of [obese/overweight] men likely result in fat mass expansion, conferring increased capacity for enlarged adipocytes to express adipokines and increase fatty acid supplies,” Ribeiro and colleagues wrote. “[This] might impact the local energy and availability of growth factors, thereby causing the local environment to allow cancer progression.”

Periprostatic adipose tissue gene expressions of obese/overweight and prostate cancer patients create an environment for the progression of prostate cancer, the study concluded.

“In an increasingly obese population, understanding how fat — especially the fat surrounding the prostate — can influence growth and severity of prostate cancer may provide an opportunity for implementing personalized lifestyle and therapeutic strategies,” Ribeiro said in a press release.