[Immunohistochemical expression of epidermal growth factor and its prognostic value for gastrointestinal stromal tumors]. / Determinación inmunohistoquímica y utilidad pronóstica del receptor del factor de crecimiento epidérmico en los tumores estromales gastrointestinales.

ABSTRACT

INTRODUCTION: The epidermal growth factor receptor, EGFR (HER-1), is a tyrosine kinase receptor. EGFR activation plays an important role in increased cell proliferation, angiogenesis, and decreased apoptosis. Our objective was to study EGFR immuno-expression in GIST, as well as its prognostic value. PATIENTS AND METHOD: A retrospective study that included all patients operated on with a histologic diagnosis of GIST at Department of Surgery, Hospital General, Ciudad Real, between 1995 and 2007. CLINICAL FEATURES age, sex, manifestations, mortality, recurrence. Pathological features origin, size, tumoral necrosis, mitotic index, cell type. Immunohistochemical features vimentin, (V9, Dako A/s); smooth muscle actin (HHF-35, Biogenex); CD34 (QBEND/10); S100 (Policlonal Dako A/S), CD117, (c-kit Rabbit, antihuman polyclonal antibody, 1600); PDGFR-alfa (Rabbit polyclonal antibody, 150, Sta. Cruz Biotechnology). Prognostic molecular features P-53, PAb240 (DakoCytomation) 175; Ki-67, clona MIBI (Dako, Denmark). Malignancy criteria Fletcher's criteria. RESULTS: From 1995 to 2007, 35 GISTs were resected in our Department. Mean age 61.11 +/- 11.02, with a female predominance of 62.9%. Initial clinical manifestation included digestive hemorrhage in 40%. Median follow-up was 28 months (3-133). Mortality was 54.3%, and recurrence rate was 40%. The most frequent origin was the stomach, 51.4%, (18). There was tumor necrosis in 57.1% (20). There were spindle-like cells in 57.1%, and epithelioid cells in 14.3%. Mean size was 9.58 +/- 6.29. Mitotic index per 50 high-power fields was 13.44 +/- 16.08; 51.45% (18) were high-risk tumors. Immunohistochemical expression CD117+, 85.7%. PDGFRA+, 85.7%. CD34+, 77.1%. EGFR+, 62.9%. S100+, 34.3%. Actin+, 20%. Vimentin+, 100%. p53+, 40%. ki67+, 10.71 +/- 10.82. There was no correlation between EGFR expression and recurrence and/ or mortality, p = 0.156 and p = 0.332, respectively. Mitosis index related to mortality, p = 0.02, and recurrence, p = 0.013. CONCLUSION: In our study there was no relation between EGFR immunohistochemical expression and the prognosis of GIST.