Table 1.

Relationship between protective role of PPARγ expression and efficacy of TZDs in therapy.

Cancer type	Role of PPARγ	TZD	Experimental model	Result	Reference
		PIO	Xenograft (HT-29) in mice with APC mutation, sc	Increased tumor growth	[41]
Colon	⇓/⇑		Azoxymethane-induced murine tumors	Reduced tumor growth	[39]
		TRO	HT-29 xenografts, sc	Reduced tumor growth and metastasis	[40]
			Metastatic colon cancer, 25 patients	All progressive disease	[43]
Lung	⇓/⇑	ROSI	Chemically-induced mouse model	Decrease in adenoma formation	[46]
		ROSI	LMM3 injection into mice, sc	Decreased tumor growth	[48]
Breast	⇓		Chemically induced rat model	Decreased tumor growth and incidence	[49]
		TRO	Advanced chemotherapy breast refractory cancer, 22 patients	No CR or PR, 3 SD	[50]
		ROSI	Early stage breast cancer, 38 patients	No decrease in proliferation	[51]
		PIO	PC3 xenografts, sc.	Decrease of bone-invasive potential	[53]
Prostate	⇓	TRO	Advanced prostate carcinoma, 41 patients	Stabilization of PSA levels	[54]
		ROSI	Recurrent prostate carcinoma, 1 patient	Delayed increase of PSA levels	[55]
Glioma	⟺	PIO	LN229 orthotopic xenografts	Reduced tumor volume, invasion	[58]
			Chemorefractory glioma, 14 patients	Disease stabilization (29%)	[59]
Melanoma	⟺	CIGLI	A375 xenografts, sc.	Growth inhibition, pro-apoptotic effects	[62]
		PIO	Transgenic mouse model (PPAR fusion protein/PTEN deletion)	Decreased tumor growth and metastasis	[106]
Thyroid	⇓	ROSI	Transgenic mouse model (Thyroid hormone receptor-β negative)	Delayed progression	[107]
			Metastatic thyroid cancer, 1 patient	Decrease in metastasis size	[109]

PPARγ expression on tumor progression: promotion: ⇑; protection: ⇓; no effect: ⟺; CR: complete response; PR: partial response; SD: stable disease; sc: subcutaneous implantation of tumor cells.