It has been demonstrated that epithelial tumour cells secrete antiadipogenic cytokines (TNF-α, IL-11 and IL-6) and prostaglandin E2 (PGE2) which inhibit the differentiation of fibroblasts into mature adipocytes near the tumour through selective inhibition of the expression of PPARγ and C/EBPα, which are involved in adipogenic differentiation [49] (Figure 4). This evidence concerns the gene PPARG and neoplasm.