Aberrant Expression of Peroxisome Proliferator-Activated Receptors in Colorectal Cancer and Their Association with Cancer Progression and Prognosis

Introduction: Peroxisome proliferator-activated receptors (PPARs), PPAR alpha, PPAR gamma, and PPAR delta, are nuclear ligand-activated transcription factors which presumably contribute to a broad range of pathophysiological processes, such as tumorigenesis. Nevertheless, their exact role as tumor suppressors or promoters is not straightforward in colorectal cancer (CRC). Therefore, expression values of these PPARs and their relation with tumor progression and prognosis were examined in CRC patients. Methods: In this work, the relative expression values of the PPARs were measured by real-time polymerase chain reaction in 100 CRC tumor tissues paired with adjacent normal tissues. After that, the association between relative expression values of the PPARs in tumor tissues and the cancer progression-related clinicopathological characteristics as well as overall survival of patients were assessed. Results: While PPAR alpha and PPAR delta seemed to be overexpressed, PPAR gamma was suppressed in CRC tumor tissues compared with paired adjacent normal tissues (p = 0.0001). The relative expressions of PPAR alpha and PPAR delta were negatively associated with tumor size, tumor grade, TNM stage, metastasis, lymphatic invasion, and decreased overall survival time (p < 0.05). The same associations, but in reverse direction, were found for PPAR gamma. Conclusions: It was found that PPAR alpha and PPAR delta were overexpressed while PPAR gamma was suppressed in CRC tumor tissues, and these deregulations are associated with cancer progression and poor prognosis. (c) 2019 The Author(s) Published by S. Karger AG, Basel