• 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.
• Molecular Oncology Group, Portuguese Institute of Oncology, Ed, Laboratórios-Piso 4, Rua Dr, António Bernardino de Almeida 4200-072, Porto, Portugal. oriebir.r@gmail.com
• Bmc Med. 2012 Sep 25; 10: 108.

BackgroundPeriprostatic (PP) adipose tissue surrounds the prostate, an organ with a high predisposition to become malignant. Frequently, growing prostatic tumor cells extend beyond the prostatic organ towards this fat depot. This study aimed to determine the genome-wide expression of genes in PP adipose tissue in obesity/overweight (OB/OW) and prostate cancer patients.MethodsDifferentially expressed genes in human PP adipose tissue were identified using microarrays. Analyses were conducted according to the donors' body mass index characteristics (OB/OW versus lean) and prostate disease (extra prostatic cancer versus organ confined prostate cancer versus benign prostatic hyperplasia). Selected genes with altered expression were validated by real-time PCR. Ingenuity Pathway Analysis (IPA) was used to investigate gene ontology, canonical pathways and functional networks.ResultsIn the PP adipose tissue of OB/OW subjects, we found altered expression of genes encoding molecules involved in adipogenic/anti-lipolytic, proliferative/anti-apoptotic, and mild immunoinflammatory processes (for example, FADS1, down-regulated, and LEP and ANGPT1, both up-regulated). Conversely, in the PP adipose tissue of subjects with prostate cancer, altered genes were related to adipose tissue cellular activity (increased cell proliferation/differentiation, cell cycle activation and anti-apoptosis), whereas a downward impact on immunity and inflammation was also observed, mostly related to the complement (down-regulation of CFH). Interestingly, we found that the microRNA MIRLET7A2 was overexpressed in the PP adipose tissue of prostate cancer patients.ConclusionsObesity and excess adiposity modified the expression of PP adipose tissue genes to ultimately foster fat mass growth. In patients with prostate cancer the expression profile of PP adipose tissue accounted for hypercellularity and reduced immunosurveillance. Both findings may be liable to promote a favorable environment for prostate cancer progression.

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