August 16, 2023
1. What does the "wild-type gastrointestinal stromal tumor" in the clinical report mean?
Although many GIST are related to the activation mutations of KIT and PDGFRA genes, there are still some GIST (10%) without exon mutations of these two genes, which are called "wild type" GIST. At present, it is believed that wild-type GIST is not without gene mutation, but the corresponding genomics, transcriptome and epigenetic etiology have not been found yet. In recent years, it has been found that about 25% of wild-type GIST has SDH (succinate dehydrogenase complex) gene mutations. SDH mutations are mainly SDHA, followed by SDHB and SDHC. SDHA mutation leads to abnormal SDH function, which may promote angiogenesis and tumor proliferation through hypoxia.
The GIST of SDH deficiency mainly includes GIST and Carney triad in children. SDH defect GIST usually occurs in the stomach, but its histological features are special, such as proliferation of epithelial cells, plexiform hyperplasia of lamina propria and invasion and metastasis of lymphoid vessels. At present, it is controversial whether the wild-type GIST needs imatinib adjuvant therapy, because the wild-type GIST itself develops slowly and reacts poorly to imatinib.
2. How to diagnose and evaluate the condition of gastrointestinal stromal tumor before operation?
Once the gastrointestinal stromal tumor is diagnosed, it is best to go to the regular hospital for treatment. The doctor will make the best treatment plan for the gastrointestinal stromal tumor according to the patient's whole body condition, disease progress and other factors. Endoscopy, endoscopic ultrasonography and CT can initially diagnose GIST, but because of few biopsy samples, it is difficult to make a diagnosis before operation. Note that preoperative GIST biopsies can be performed, especially when tyrosine kinase inhibitors (tyrosine kinase inhibitor, TKI) are proposed for neoadjuvant targeting therapy, but GIST metastasis caused by biopsy should be avoided.
[doctor reminds].
Endoscopic ultrasound biopsy is recommended rather than percutaneous biopsy, but it is not restricted if the tumor has been widely metastasized. It should be pointed out that if GIST is suspected clinically and the tumor can be completely removed (except for combined resection of multiple organs), there is no need for preoperative biopsy and preoperative TKI treatment, but can be treated directly. Because surgery is still the preferred method for the treatment of localized GIST.
