RESUMEN
<p><b>OBJECTIVE</b>To observe the expression of FLI-1 in primitive neuroectodermal tumors (PNET), explore the value of immunohistochemical staining of FLI-1 in combination with other neural markers in diagnosis of PNET, and analyze the prognostic factors in PNET patients.</p><p><b>METHODS</b>35 cases of PNET, of which 33 cases with complete clinical data, were included in this study. Immmunohistochemistry (The En Vision method) was applied to detect the expression of FLI-1, CD99, Syn, NSE, S-100, NF, Vim in the tumor tissues. The clinicopathological data of 33 cases were analyzed by Cox regression.</p><p><b>RESULTS</b>The positive expression rate of FLI-1 were 51.4% and that of CD99 was 88.6%. The sensitivity of FLI-1 combined with CD99 was up to 100%. The positive rates of Vim, Syn, NSE, s-100 and NF were 91.4%, 48.6%, 45.7%, 22.9% and 0, respectively. Cox regression analysis showed that the impact of primary location and treatment modality were of statistical significance (P < 0.05), but the age, sex, stage or size of tumors did not (P > 0.05).</p><p><b>CONCLUSION</b>Immunohistochemical detection of FLI-1 and neural markers is a preferred method for clinical diagnosis of PNET. The main factors affecting the prognosis are the primary location of PNET and treatment modality.</p>