KIT and gastrointestinal stromal tumor: In conclusion, this study illustrates several new and interesting aspects regarding imatinib treatment in malignant GIST, including a role for neoadjuvant treatment that may allow surgical resection of large primary tumours and metastases; a high response rate to imatinib in patients whose tumours have exon 11 KIT mutations; a potential role for imatinib even in patients without exon 11 mutations; and histologic documentation of different tumour responses to imatinib corresponding clinically to reduction in tumour volume.