Correlations between papillary thyroid cancer and peripheral blood levels of matrix metalloproteinase-2, matrix metalloproteinase-9, tissue inhibitor of metalloproteinase-1, and tissue inhibitor of metalloproteinase-2
1. Department of General Surgery, Qilu Hospital, Shandong University,Jinan, Shandong 250012, China 2. Department of General Surgery, Qingdao Municipal Hospital,Qingdao, Shandong 266071, China