Association of the mRNA expression and promoter methylation about p73 gene in the tissues of nephroblastoma

Abstract

Objective To investigate the expression and promoter methylation status of p73 gene in children with nephroblastoma and their clinicopathological correlations. Methods The methylation-specific PCR and real-time quantitative PCR were used to detect the mRNA expression and methylation status of p73 gene in 38 cases of nephroblastoma, 15 cases of adjacent tumor and 15 cases of normal renal tissues, then their clinicopathological correlations and how the p73 gene methylation affected its transcription were analyzed. Results Relative quantity(RQ) of p73 mRNA in tumor tissues was 0.79±0.21, 0.74±0.19 in peritumoral tissues, and 0.48±0.17 in normal renal tissues, and differences among the 3 groups were statistically significant, in which tumor and peritumoral tissues were higher than normal tissues(all P 0.05). p73 gene methylation-positive rate in tumor was 26.3%(10/38 cases), adjacent tumor was 33.3%(5/15 cases), normal kidney tissue was 80.0%(12/15 cases), and differences among the 3 groups were statistically significant, in which tumor and peritumoral tissues were both lower than normal tissues(all P 0.05). Difference in RQ values among methylated tumor, adjacent tumor and normal renal tissues was statistically significant(P=0.000), in which tumor and adjacent tumor were both higher than normal renal tissues(P<0.05); But difference of RQ value among unmethylated tumor, adjacent tumor and normal renal tissues was not statistically significant(P=0.075). Conclusions The close correlation between p73 low methylation and high mRNA expression suggests that aberrant promoter methylation is possibly one of the gene expression regulations, and also connected with the development of nephroblastoma.The p73 gene in methylated nephroblastoma may play the role of oncogenes, as there is a negative correlation tendency between the overexpression in transcriptional level and its methylation status. Key words: p73; Nephroblastoma; Tissue; Promoter methylation; mRNA expression