Objective: To evaluate the expression of TEIF protein in human tumors of soft tissue and its significance.
Methods: Anti-TEIF polyclonal antibody was generated by immunization of E.coli expressed His-TEIF protein. The expression of TEIF in 166 cases of sarcomas and 28 case benign tumors or tumor-like lesions of soft tissue arranged in tissue chip was analyzed by immunohistochemistry.
Results: Polyclonal antibody obtained from immunized rabbit was verified in Western blot to prove its specific reactivity with native TEIF protein. The immunohistochemical staining of TEIF showed that about 58% (97/166) of sarcomas were positive and significantly different from that of benign tumors or tumor-like lesions (11%, 3/28). The positive staining was predominantly in synovial sarcoma 94% (16/17), primitive neuroectodermal tumor (PNET) 91% (21/23), both of which were significantly higher than 43% (6/14) of dermatofibrosarcoma protuberans, 38% (6/16) of myxofibrosarcoma, 36% (8/22) of malignant peripheral nerve sheath tumor, 32% (6/19) of liposarcoma, (P < 0.05, respectively), but not higher than 75% (15/20) of malignant fibrous histiocytoma, 70% (7/10) of rhabdomyosarcoma or 64% (9/14) of leiomyosarcoma. Meanwhile, strong positive staining of TEIF (>or= 2+) was frequently observed in PNET (83%, 19/23) and synovial sarcoma (76%, 13/17). With respect to FNCLCC grading, 19 cases of grade I sarcoma TEIF was 32% (6/19) and strong positive was 11% (2/19), 44 cases of grade II sarcoma was 48% (21/44) and 32% (14/44), and 70 of grade III was 84% (59/70) and 70% (49/70). The rate of either positive or strong positive in grade III sarcoma was significantly different from that of either grade I or II (P < 0.05), but no difference between the latter two groups (P > 0.05).
Conclusions: TEIF protein could be detected in large part of soft tissue sarcomas, and it not only over-expressed in most of PNET, synovial sarcomas, but also correlated with histological grading.