Analysis in mutation profile of c-kit and platelet derived growth factor receptor A gene exon and clinicopathological characteristics in gastrointestinal stromal tumors

  Objective  To analyze the types and characteristics of c-kit and platelet derived growth factor receptor A (PDGFRA) gene mutations in gastrointestinal stromal tumors (GIST) and their relationships with clinicopathological characteristics of GIST.

  Methods  The clinicopathological data and tumor tissue specimens of 288 patients with GIST were collected, and the polymerase chain reaction amplification-direct sequencing method was used to detect the mutation status of c-kit (exons 9, 11, 13, 17) and PDGFRA gene (exons 12, 18), and the relationships between mutation types, sites and clinicopathological characteristics were analyzed.

  Results  Among the 288 GIST cases, 244 cases were primary mutations type (84.72%), 10 cases were secondary drug-resistant mutations type (3.47%), and 34 cases were wild-type (11.81%). Among the 244 patients with primary mutant GIST, there were 231 (94.67%) mutations in the c-kit gene, and the mutations in exons 9, 11, 13, and 17 were 25, 189, 7, and 10 cases, respectively. There were 13 cases with PDGFRA gene mutation, of which exon 12 and 18 mutations were 3 and 10 cases, respectively. Among 189 cases with c-kit gene exon 11 mutations, 111 cases (58.73%) were deletion mutations, 65 cases (34.39%) were point mutations, 3 cases were repeated mutations (1.59%), 4 cases were insertion mutations (2.12%), and 6 cases were mixed mutations (3.17%). The hot spot of exon 11 mutation was codons 557 to 560. The mutation site was related to the primary tumor site, tumor size and mitotic count (P < 0.05). The type of mutation was related to the patient's age, primary site of tumor, tumor size, mitotic count and modified National Institutes of Health (NIH) risk classification (P < 0.05). Logistic regression analysis showed that GIST patients aged more than 60 years old, with deletion mutations and c-kit exon 11 mutations had an increased risk of modified NIH risk classification by 2.060 (95%CI was 1.066 to 3.980), 3.264 (95%CI was 1.628 to 6.545) and 3.819 (95%CI was 1.585 to 9.205) times.

  Conclusion  The c-kit and PDGFRA genes in GIST have a high mutation rate and diverse mutation types or sites, which are closely related to the clinicopathology and prognosis of GIST patients, and can provide a reference for the whole-process management of GIST.