Abstract: Objective To investigate the expression of peptidyl demitasse isoform 2(PADI2), a PAD family member, in various tumor tissues and the blood of patients and to investigate the correlation between PADI2 encoding gene and tumor risks. Methods Sequenom MassARRAY genotyping assay was used to determine the potential association of tag single nucleotide polymorphisms(SNPs)including rs2746533, rs79395834, rs2076616, rs10788656 in PADI2 gene to various tumor types(breast cancer, cervical cancer, esophageal cancer, stomach cancer, liver cancer, lung cancer, ovarian cancer, colon cancer, rectal cancer and thyroid cancer). Immunohistochemistry was used to determine the PADI2 expression and location in tumor tissues. ELISA was used to detect the PADI2 level in blood of the tumor 山 东 大 学 学 报 (医 学 版)55卷11期 -李昌,等.PADI2与人多种肿瘤的遗传易感性的关系 \=-patients. Results The case-control analysis showed a significant association between rs2746533, rs2076616 and rs10788656 and breast cancer, cervical carcinoma, esophageal carcinoma, gastric carcinoma, lung cancer and rectal carcinoma risks. PADI2 expression significantly increased in 95% of the patients with breast invasive ductal carcinoma, 97.5% of the patients with colonal adenocarcinoma, 88% of the patients with esophageal squamous cell carcinoma, and 92.5% of the patients with lung cancers and 90% of thyroid carcinoma papillary carcinoma samples, but not in the corresponding healthy tissues, except that in some mesenchymal cells and endothelial cells. A two-fold increase in PADI2 expression was detected in the blood of 86% of patients with liver cancer, 38% of patients with cervical carcinoma and 32% of patients with gastric carcinoma. Conclusion PADI2 has genetic susceptibility to many kinds of tumor and is highly expressed in various tumor tissues and blood of the patients. The finding suggests an important role for PADI2 in tumorigenesis.

Key words: Susceptibility gene, Tumor, Gene expression, Peptidyl deiminase isoform 2, Genotype