Background and purpose: PLAGL1 gene is a newly discovered gene

which could induce tumor cells’ apoptosis and cell cycle arrest. This study aimed to investigate the expression and the promoter methylation level of PLAGL1 gene and its correlation with SDHB gene mutations in pheochromocytoma. Methods: The expressions of PLAGL1 mRNA was detected by real-time quantitative reverse transcription polymerase chain reaction (qRT-PCR) method in 13 cases of normal adrenal medulla

32 cases of benign pheochromocytoma group and 54 cases of malignant pheochromocytoma. We examined the promoter methylation status by methylation-specific polymerase chain reaction (MSP) and SDHB gene mutation by qRT-PCR amplification and direct sequencing. Results: The relative expression volume of PLAGL1 gene in malignant tumor tissue was (0.527±0.201)

which was significant lower than those in benign tumor tissue and normal adrenal medulla[(1.517±0.662) and (1.734±0.756)]. There was no remarkable difference between benign tumor tissue and normal tissue for PLAGL1 gene expression and promoter methylation. PLAGL1 gene methylation rate in malignant tumor tissue

benign tumor tissue and normal adrenal medulla were 68.5%

18.8% and 15.4% respectively. SDHB gene mutation was detected in 7 malignant tumor tissues

while no mutation was found in benign and normal group. Conclusion: Lower expression status of PLAGL1 gene showed significant correlation with promoter methylation which may be associated with SDHB gene mutation.