Abstract: Objective:To investigate the expression of Gli- 2 protein and nuclear proliferation marker Ki- 67in human thymic tu -mors, as well as its relationship with clinicopathological features and prognosis. Methods:Immunohistochemical staining was per-formed to determine the expressions of Gli- 2 and Ki-67in 64thymic tumor cases, in which 9 were type A,6 were type AB, 11 were type B 1, 22were type B 2, and 16were type C.Results: 1) Positive expression rates of Gli- 2 in types A, AB, B1, B2, and C thymomas were 1/9 (11 .11 %),2/6 (33.33%),2/11 (18.18%),5/22(22.73%), and13/16(81.25%), respectively. Statistically significant differences
existed in the two sets of data (P<0.05). Positive rates of Gli- 2 in the Masaoka stages Ⅰ, Ⅱ, Ⅲ, and Ⅳwere 2/10(20% ), 12/41 (29.27%),4/6 (66.67%), and5/7 (71.43%), respectively. The statistical differences of these two sets of data were also significant (P< 0.05). 2) The expression levels of Gli- 2 in tumor tissues were closely correlated with the pleura (P<0.05) but not associated with gen -der, age, myasthenia gravis, and necrosis with hemorrhage (P>0.05). 3) The positive labeling indexes of Ki-67in invasive and non-inva -sive thymomas were 7.14± 6.99and 15.24± 9.13, respectively. The differences between both thymomas were statistically significant (P<0.05). 4) A positive correlation existed in the expression of Ki-67and Gli-2 in thymomas. Five-year progression-free survival (PFS) rate was lower in the Gli- 2 positive group (56.5%,13/23) than in the negative group ( 92.7%,38/41). The Ki-67-positive group ( 61.5%, 16/26) also showed a lower five-year PFS than that in the negative group ( 92.1%,35/38), with statistically significant differences be-tween the two groups ( P<0.05). Multivariate Cox's proportional hazard regression analysis indicated that the Gli- 2-positive group ex -pression, Ki-67-positive group expression, and invasion of the pleura were independent prognostic factors of thymic tumors. Conclu-sion:The expression of Gli-2 and Ki-67showed a positive correlation with thymic tumors. Detecting the combined expression of Gli- 2 and Ki-67may elucidate the clinicopathological features and prognoses of patients with thymic tumors.