Prostate cancer is one of the most
common cancers in men and early treatment is usually very
successful. However, like other cancers, obesity increases the risk
of aggressive prostate disease. New research, published in BioMed
Central's open access journal BMC Medicine, finds that the fat
surrounding the prostate of overweight or obese men with prostate
cancer provides a favorable environment to promote cancer growth.
Fat is a generally underrated organ. Not
only is it an energy store but it secretes a wide range of growth
factors, cytokines and hormones, including leptin and adiponectin,
and is a major player in the immune system, which protects the body
from infection and disease. But too much fat can cause these systems
to go haywire and can increase risk of diabetes, cardiovascular
disease and cancer.
An international team led by Prof Gema
Frühbeck and Dr Ricardo Ribeiro analyzed fat, from around the
prostate, taken from patients undergoing surgery for prostate
disease. Samples were included from men with benign prostatic
hyperplasia (BPH), prostate cancer (PC), and from men where their
cancer was no longer confined to the prostate. The men were also
classified as being either lean (BMI<25) or overweight /obese
Regardless of type of prostate disease
the overweight men had different levels of gene activity in the fat
surrounding their prostates compared to the lean men. This included
genes which encode proteins involved in immunity and inflammation
(such as LEP, which encodes the protein leptin), and cell growth and
proliferation (including ANGPT1 which encodes angiopoietin 1), fat
metabolism and programmed cell death.
Additionally the activity of more genes
was altered between hyperplasia and prostate cancer, and between
cancer and non-confined cancer, suggesting a gradual increase in
dysregulation during cancer progression.
Prof Frühbeck explained, "Both LEP and
ANGPT1 encode proteins which are thought to have roles beyond
adipose tissue itself, especially because prostate cancer cells have
receptors for leptin, and angiopoietin 1. Taken together with the
abnormal activity levels of other genes they will ultimately foster
fat mass growth, reduce immune surveillance, and promote the
formation of new blood vessels, so producing a favorable environment
for prostate cancer progression."
Dr Ribeiro continued, "In an
increasingly obese population, understanding how fat, especially the
fat surrounding the prostate, can influence the growth and severity
of prostate cancer may provide an opportunity for implementing
personalized lifestyle and therapeutic strategies."
For more information
Ricardo Ribeiro, Cátia Monteiro, Victoria Catalán, Pingzhao Hu,
Virgínia Cunha, Amaia Rodríguez, Javier Gómez-Ambrosi, Avelino Fraga,
Paulo Príncipe, Carlos Lobato, Francisco Lobo, António Morais, Vitor
Silva, José Sanches-Magalhães, Jorge Oliveira, Francisco Pina,
Carlos Lopes, Rui Medeiros and Gema Frühbeck
Obesity and prostate cancer: gene
expression signature of human periprostatic adipose tissue.