Results on prognostic value of mutations in localized gastrointestinal stromal tumors (GIST) in one single center.

INTRODUCTION to study the prognostic value of mutations in KIT or PDGFRA in gastrointestinal stromal tumors (GIST) managed in our department. MATERIALS AND METHODS forty five patients with localized GIST underwent surgery between 1998 and 2010. Thirty six patients were enrolled in a retrospective study. DNA was isolated from 3 to 5 ìm sections of fixed and paraffin-embedded tissue. Exon 9, 11, 13 and 17 of c-kit gene and exon 12 and 18 of PDGFRA were amplified by PCR and sequenced. RESULTS tumors with mutations were larger at the surgery and showed higher mitotic count (p < 0.05). The mutations were found in 22 patients (61.2%), 18 had mutations in exon 11 of c-kit gene. PDGFRA mutations were located in exon 12. The 5-years relapsefree survival rate for patients with tumors having mutations was 38% and 100% for patients without mutations (p < 0.01). The 5-year survival rate was significantly worse for patients with mutations (20 vs. 97%, p < 0.01), with tumors larger than 5 cm (28 vs. 97%, p < 0.01) and with > 50 mitosis/HPF (42 vs. 88%, p < 0.03). Multivariate analyses indicated that the mutations, mitotic counts, and tumor size were independent prognostic factors for survival in patients with localized GIST. CONCLUSIONS in this series, having a detected mutation is a poor prognostic factor with significantly increased recurrence rate and shortens survival.