Analysis of KIT mutations and c-KIT expression in Chinese Uyghur and Han patients with melanoma.

Abstract

The KIT gene plays an important role in the pathogenesis of malignant melanoma (MM). In recent years, activating mutations in KIT have been recognized as oncogenic. A number of therapies have been established, which provide significant clinical benefits for patients with MM with KIT mutations. Thus, detection of KIT mutations can have profound therapeutic implications. To investigate KIT gene expression in MMs in Chinese Uyghur and Han patients with mutations in KIT, and to identify the clinical features associated with KIT mutations and c-KIT expression. In total, 105 MMs (56 from Uyghur and 49 from Han patients) were selected from patients in the Uyghur Autonomous region. Formalin-fixed, paraffin wax-embedded tumour sections were analysed for c-KIT expression using immunohistochemistry. Exons 11 and 13 of KIT were analysed for the presence of mutations using PCR amplification and DNA sequencing. Of the 105 MMs, 13 (10 Han and 3 Uyghur) were found to have mutations in KIT. Thus, the frequency of KIT mutations in Han patients was significantly higher than that in Uyghur patients (P=0.02). We detected c-KIT expression in 71.4% and 42.9% of the tumour tissue samples collected from the Uyghur and Han patients, respectively. In the Xinjiang Uyghur Autonomous Region in China, chronic sun-induced damage MM is the most prevalent MM among Chinese Uyghur patients, whereas acral and mucosal MMs are the most prevalent in Uyghur patients. Mutations in the KIT gene do not correlate with c-KIT expression.