Abstract: Obiective Narrow down the candidate regions of sporadic pheochromacytoma(PCC). Methods Total of 42 patients who were clinically diagnosed as sporadic PCC from 2011-9 to 2013-5 in PUMCH were enrolled. Extract whole genome DNA from their tumors as well as peripheral blood leukocytes. Then exclude inherited cases by Sanger sequence mutation. Within 14 verified cases of sporadic PCC, apply single nucleotide polymorphism (SNP) chip to detect whole genome DNA copy number variations (CNV) and loss of heterozygosity (LOH) to initially locate the hot regions. Finally Apply Q-PCR to confirm the hot regions in left cases. Results In this study 38 cases were identified as sporadic PCC, and 4 as inherited cases. CNV were detected in 14/14 tumors, of which deletions were more common. Missing regions occurred in 1p、3q、17p、22q、11p. On the other hand, of the 3 inherited cases, deletion was also detected. The loss of parts of arm 1p is the most common, including chr1:74,957,006～86, 132,879, chr1:58,096,424～67,700,471, and chr1:98,902,091～107,622,430. The result of Q-PCR confirmed the above-mentioned three regions, and the three segments are final candidate regions. Conclusion Part deletions of 1p in most cases are the most striking phenomenon, which indicating part deletions of 1p may occur with PCC development, and there may be some tumor suppressor gene(s) within these areas.

Key words: sporadic pheochromacytomas, single nucleotide polymorphism chip, genes