Gastrointestinal stromal tumors (GISTs): a review.
ABSTRACT Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal neoplasms in the gastrointestinal tract, which, over the last 10 years, have emerged from a poorly understood neoplasm to a well-defined tumor entity exhibiting particular molecular abnormalities and for which promising novel treatment modalities have been developed. GISTs probably arise from the precursor cell of the interstitial cell of Cajal, express KIT tyrosine kinase in most of the cases and harbor mutations of importance for individualized treatment. The molecular targets for therapeutic interventions are not only of importance for the treatment of GIST patients but also useful for in the development of novel drug modalities and new strategies in basic cancer therapy.
Article: GIST suture-line recurrence at a gastrojejunal anastomosis 8 years after gastrectomy: can GIST ever be described as truly benign? A case report.[show abstract] [hide abstract]
ABSTRACT: We present the case of a 71 year old man with recurrence of a Gastro Intestinal Stromal Tumour (GIST) at the gastrojejunal anastomosis eight years following partial gastrectomy for a very small primary gastric GIST. He presented acutely on both occasions with haemodynamic shock secondary to massive haematemesis. During his initial presentation in 2001, an emergency laparotomy was performed, demonstrating a pre-pyloric ulcerative lesion. The histopathology was in keeping with a diagnosis of a gastric GIST with a <2 cm tumour, with <5 mitosis per 50/HPF, no signs of necrosis and invasion limited to the mucosa. Eight years later the same patient presented with a similar clinical picture of haemodynamic instability secondary to haematemesis. Emergency endoscopy showed an irregularly shaped elevated lesion on the gastrojejunostomy line suggestive of recurrence. He subsequently underwent completion gastrectomy and the histology revealed a 0.8 cm GIST tumour composed of spindle cells with <5 mitosis per 50/HPF, tumor invasion into the submucosa and positive expression of c-kit and SMA. The patient remains recurrence free 18 months post surgery. The literature suggests that tumour size, mitotic rate and tumour site are the most important predictive factors of recurrence. Additional features such as the presence of necrosis, local tumour invasion and positive resection margins, can also influence recurrence rates. In this case the lesion was a gastric GIST, very small (<2 cm), had low proliferation rate (<5 mitosis/HPF), lacked necrosis and was limited to the mucosa. Recurrence of such a primary GIST at the anastomotic line, eight years after initial resection has never been demonstrated among review of several thousand primary GISTs. This case highlights how even the most innocent GISTs can never be described as truly benign.World Journal of Surgical Oncology 10/2010; 8:90. · 1.12 Impact Factor
Article: Canine and human gastrointestinal stromal tumors display similar mutations in c-KIT exon 11.[show abstract] [hide abstract]
ABSTRACT: Gastrointestinal stromal tumors (GISTs) are common mesenchymal neoplasms in the gastrointestinal tract of humans and dogs. Little is known about the pathogenesis of these tumors. This study evaluated the role of c-KIT in canine GISTs; specifically, we investigated activating mutations in exons 8, 9, 11, 13, and 17 of c-KIT and exons 12, 14, and 18 of platelet-derived growth factor receptor, alpha polypeptide (PDGFRA), all of which have been implicated in human GISTs. Seventeen canine GISTs all confirmed to be positive for KIT immunostaining were studied. Exons 8, 9, 11, 13 and 17 of c-KIT and exons 12, 14, and 18 of PDGFRA, were amplified from DNA isolated from formalin-fixed paraffin-embedded samples. Of these seventeen cases, six amplicons of exon 11 of c-KIT showed aberrant bands on gel electrophoresis. Sequencing of these amplicons revealed heterozygous in-frame deletions in six cases. The mutations include two different but overlapping six base pair deletions. Exons 8, 9, 13, and 17 of c-KIT and exons 12, 14, and 18 of PDGFRA had no abnormalities detected by electrophoresis and sequencing did not reveal any mutations, other than synonymous single nucleotide polymorphisms (SNPs) found in exon 11 of c-KIT and exons 12 and 14 of PDGFRA. The deletion mutations detected in canine GISTs are similar to those previously found in the juxtamembrane domain of c-KIT in canine cutaneous mast cell tumors in our laboratory as well as to those reported in human GISTs. Interestingly, none of the other c-KIT or PDGFRA exons showed any abnormalities in our cases. This finding underlines the critical importance of c-KIT in the pathophysiology of canine GISTs. The expression of KIT and the identification of these activating mutations in c-KIT implicate KIT in the pathogenesis of these tumors. Our results indicate that mutations in c-KIT may be of prognostic significance and that targeting KIT may be a rational approach to treatment of these malignant tumors. This study further demonstrates that spontaneously occurring canine GISTs share molecular features with human GISTs and are an appropriate model for human GISTs.BMC Cancer 10/2010; 10:559. · 3.01 Impact Factor
Article: A Malignant Gastrointestinal Stromal Tumor of the Gallbladder Immunoreactive for PDGFRA and Negative for CD 117 Antigen (c-KIT).[show abstract] [hide abstract]
ABSTRACT: Gastrointestinal stromal tumors (GISTs) compose the largest category of well-recognized nonepithelial neoplasms of the gastrointestinal tract (GI). GISTs of the gallbladder are extremely rare tumors. Only four malignant, two benign and one GIST-like tumor of the gall bladder have ever been described. The four malignant GISTs were all positive for CD 117 antigen (c-kit). We present for the first time a malignant gastrointestinal stromal tumor of the gallbladder, immunoreactive for platelet-derived growth factor receptor alpha (PDGFRA) and negative for CD 117 antigen (c-KIT).HPB Surgery 01/2011; 2011:327192.