The Expression And Significance Of PTEN And PDCD4in Nephroblastoma

BackgroundNephroblastoma, also referred to as Wilms tumor (WT), is the most common malignant tumor found in the urinary system of the infant. Tumorigenesis is closely related to abnormal cell apoptosis, one of the significant causes of which is the deactivation of tumor suppressor gene and the disorder of signal pathway. The phosphatase and tensin homolog deleted on the chromosome10(PTEN) is a recently discovered anti-cancer gene which possesses the activity of phosphatase. It can block the PI3K/Akt signaling pathway, inhibit cell proliferation and stimulate cell apoptosis. Programmed cell death4(PDCD4) is another tumor suppressor that was found recently. It is a downstream molecule in the PI3K/Akt signaling pathway and can also promote cell apoptosis and inhibit tumor formation.ObjectiveTo investigate the mRNA and protein expression of PTEN and PDCD4in nephroblastoma, analyze the correlation between their expression and the clinicopathological factors involved in nephroblastoma, explore the effects of PTEN and PDCD4in tumor growth and metastasis, and try to put forward to the hypothesis that the role PTEN and PDCD4plays in PI3K/Akt signaling pathway. Provide new molecular targets for the treatment of nephroblastoma.MethodsThe mRNA and protein expression of PTEN and PDCD4in39nephroblastoma tissues and15adjacent nephroblastoma tissues (control group, located2cm away from the borderline of the tumor) were studied by reverse transcription polymerase chain reaction (RT-PCR) and immunohistochemistry. The results are then analyzed with clinical data.ResultsThe mRNA expression of PTEN and PDCD4in all39nephroblastoma tissues are down-regulated, and the mRNA OD rations of PTEN and PDCD4in the control group are twice of those in nephroblastoma tissues. The protein expression of PTEN and PDCD4in nephroblastoma tissues (positive rate:17.95%,33.33%) are significantly lower (P<0.05) than those in the control group (positive rate:93.33%,100%).The down-regulation of the protein expression of PTEN and PDCD4in nephroblastoma tissues is closely related to multiple clinicopathological factors (P<0.05), such as age, histopathological and clinical grading, and lymph node metastasis. The gender has no significant impact (P>0.05) on repressing the expression of PTEN and PDCD4in nephroblastoma tissues. A positive correlation was found between the protein expression of PTEN and that of PDCD4in nephroblastoma tissues through regression analysis (r=0.88, P<0.05).ConclusionsThe mRNA and protein expression of PTEN and PDCD4in nephroblastoma tissues are significantly lower as compared to the control group, which can be regarded as a reference index to evaluate the biological behavior of the nephroblastoma. There is positive correlation between the protein expression of PTEN and that of PDCD4in PI3K/Akt signaling pathway.