Evaluation of the expression pattern and diagnostic value of PPAR[gamma] in malignant and benign primary bone tumors

Purpose The quantifiable description of PPAR[gamma] expression pattern beside mechanistic in-vitro evidence will provide insights into the involvement of this mediator in tumor pathogenesis. This study is focused on illuminating the PPAR[gamma] gene and protein expression pattern, its association with tumor deterioration and its diagnostic value in different types of primary bone tumors. Methods The expression pattern of PPAR[gamma] was investigated in the 180 bone tissues including 90 bone tumor tissues and 90 non-cancerous bone tissues. The local PPAR[gamma] expression level was assessed using real-time qRT-PCR and the PPAR[gamma] protein expression pattern was measured using immunohistochemistry. The correlation of PPAR[gamma] expression level with patients' clinic-pathological features, also the value of the variables in predicting PPAR[gamma] expression level in tumors and the value of PPAR[gamma] to discriminate tumor subtypes were assessed. Results The mean PPAR[gamma] mRNA expression was significantly higher in bone tumors compared to healthy bone tissues, also the malignant tumors including osteosarcoma and Ewing sarcoma had the elevated level of PPAR[gamma] mRNA compared to GCT tumors. Consistently, the protein expression of PPAR[gamma] in the tumor site was significantly higher in the bone tumors and malignant tumors compared to non-cancerous and benign tumors, respectively. The PPAR[gamma] protein could predict malignant tumor features including tumor grade, metastasis and recurrence significantly. Moreover, PPAR[gamma] could potentially discriminate the patients from the controls also malignant tumors from benign tumors with significant sensitivity and specificity. Conclusions PPAR[gamma] might be involved in primary bone tumor pathogenesis and determining its molecular mechanism regarding bone cancer pathogenesis is of grave importance. Keywords: PPAR[gamma], Bone tumor, Osteosarcoma, Ewing sarcoma, GCT