TY - JOUR
T1 - Evaluation of malignancy and prognosis of gastrointestinal stromal tumors
T2 - A review
AU - Miettinen, Markku
AU - El-Rifai, Wa’El
AU - Sobin, Leslie
AU - Lasota, Jerzy
N1 - Funding Information:
Supported by the American Registry of Pathology.
PY - 2002
Y1 - 2002
N2 - This paper reviews data on the prognosis of gastrointestinal stromal tumors (GISTs). These tumors are specific KIT-expressing and KIT-signaling-driven mesenchymal tumors, many of which have KIT-activating mutations. GISTs occur in the entire gastrointestinal (GI) tract and may also arise from the omentum, mesenteries, and retroperitoneum. They range from small benign tumors to sarcomas at all sites of occurrence. A KIT tyrosine kinase inhibitor, STI-571 (imatinib [Gleevec]; Novartis, Basel, Switzerland), has recently shown promise in the treatment of metastatic GISTs. Understanding the natural history of GIST before introduction of STI-571 will help assess the impact and position of this new treatment. The frequency of benign versus malignant GISTs varies between sites. Benign GISTs outnumber malignant GISTs in the stomach, whereas malignant GISTs are more common in the intestines. Tumors that have metastasized at presentation have a very poor prognosis. Traditionally, the 3 key prognostic factors have been mitotic rate, tumor size, and site. Tumors that are small (≤2 cm) and show mitotic activity not exceeding 5 mitoses per 50 high-power fields (HPFs) have an excellent prognosis, probably independent of site, although this has not been shown specifically for all sites. In the stomach, most epithelioid GISTs are benign, provided that mitotic counts do not exceed 5/50 HPFs. However, a small proportion of tumors apparently lacking mitotic activity do metastasize. Tumors with a mitotic rate >5/50 HPFs usually have a malignant behavior. The Ki67 index may help identify tumors with malignant potential, but large site-specific series are not yet available. Genetic markers, including DNA-copy number changes, telomerase activity, and KIT mutation status, may be useful in more accurately identifying tumors with malignant potential.
AB - This paper reviews data on the prognosis of gastrointestinal stromal tumors (GISTs). These tumors are specific KIT-expressing and KIT-signaling-driven mesenchymal tumors, many of which have KIT-activating mutations. GISTs occur in the entire gastrointestinal (GI) tract and may also arise from the omentum, mesenteries, and retroperitoneum. They range from small benign tumors to sarcomas at all sites of occurrence. A KIT tyrosine kinase inhibitor, STI-571 (imatinib [Gleevec]; Novartis, Basel, Switzerland), has recently shown promise in the treatment of metastatic GISTs. Understanding the natural history of GIST before introduction of STI-571 will help assess the impact and position of this new treatment. The frequency of benign versus malignant GISTs varies between sites. Benign GISTs outnumber malignant GISTs in the stomach, whereas malignant GISTs are more common in the intestines. Tumors that have metastasized at presentation have a very poor prognosis. Traditionally, the 3 key prognostic factors have been mitotic rate, tumor size, and site. Tumors that are small (≤2 cm) and show mitotic activity not exceeding 5 mitoses per 50 high-power fields (HPFs) have an excellent prognosis, probably independent of site, although this has not been shown specifically for all sites. In the stomach, most epithelioid GISTs are benign, provided that mitotic counts do not exceed 5/50 HPFs. However, a small proportion of tumors apparently lacking mitotic activity do metastasize. Tumors with a mitotic rate >5/50 HPFs usually have a malignant behavior. The Ki67 index may help identify tumors with malignant potential, but large site-specific series are not yet available. Genetic markers, including DNA-copy number changes, telomerase activity, and KIT mutation status, may be useful in more accurately identifying tumors with malignant potential.
KW - Allelic losses
KW - Gastrointestinal stromal tumor
KW - KIT mutation
KW - Prognosis
KW - Sarcoma
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U2 - 10.1053/hupa.2002.124123
DO - 10.1053/hupa.2002.124123
M3 - Article
C2 - 12094372
AN - SCOPUS:0036301863
VL - 33
SP - 478
EP - 483
JO - Human Pathology
JF - Human Pathology
SN - 0046-8177
IS - 5
ER -