OBJECTIVETo evaluate the expression of TEIF protein in human tumors of soft tissue and its significance.

METHODSAnti-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.

RESULTSPolyclonal 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).

CONCLUSIONSTEIF 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.