Background  It still remains debatable whether peroxisome proliferator-activated receptor gamma (PPARγ) is pro- or antineoplastic, and its exact role in mycosis fungoides (MF) remains unclear.

Objective  This prospective comparative study aimed to investigate the expression of PPARγ in MF and compare it with psoriatics and controls in a trial to deduce its possible role in MF. Also, we tried to clarify the relation between PPARγ and Bcl-2 in MF.

Methods  Twenty MF patients, 20 psoriatic patients and 20 controls were included. All participants underwent a skin biopsy, and immunohistochemical staining for both PPARγ and Bcl-2 were performed. Western blot analysis was performed for detection of both PPARγ and Bcl-2.

Results  The mean area per cent of PPARγ measured in the MF patients (57.1217 ± 9.502417) was significantly higher (< 0.001) when compared with that of both the psoriatics (2.989 ± 1.723) and controls (35.9357 ± 8.1789). The mean area per cent of Bcl-2 in MF patients (9.3763 ± 6.6328) was significantly higher (< 0.001) than that of both the psoriatics (2.35 ± 1.35) and the controls (0.73105 ± 0.5302)]. Our results were confirmed using the western blot analysis. We detected a highly significant positive correlation between the PPARγ and Bcl-2 mean area per cents in all patients. In our MF patients, both parameters were also positively correlated with the age of the patient, duration and stage of MF (< 0.05).

Conclusion  Our data suggest a possible role for PPARγ in the pathogenesis of MF possibly through several mechanisms, one of which might be conferring upon the lymphoma cells, a survival advantage at least partially through up regulating Bcl-2.