Determinación inmunohistoquímica y utilidad pronóstica del receptor del factor de crecimiento epidérmico en los tumores estromales gastrointestinales

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, 1:600); PDGFR-alfa (Rabbit polyclonal antibody, 1:50, Sta. Cruz Biotechnology). Prognostic molecular features: P-53, PAb240 (DakoCytomation) 1:75; 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.