The clinical significance of KIT mutations in melanoma: a meta-analysis.

This study aimed to evaluate the association of KIT mutations with clinicopathologic features of melanomas using a meta-analysis and to identify differences between Asian and White populations using subgroup analyses. We selected 32 studies from the literature including 5224 patients. The pooled data were combined, and odds ratios (ORs) and 95% confidence intervals (CIs) were calculated. Heterogeneity and publication bias were also determined. KIT mutations were reported in 497 (9.5%) of 5224 patients with melanomas, and were associated significantly with age, clinical melanoma subtype, anatomic location, and chronic sun-damage (CSD), but not with sex, histological type, Breslow thickness, ulceration, mitotic rate, or tumor stage. The incidence of KIT mutation was significantly higher in older individuals (OR=1.296, 95% CI: 1.025-1.641; P=0.031), and showed a positive association with mucosal melanoma (OR=1.363, 95% CI: 1.094-1.697; P=0.006), acral melanoma (OR=1.374, 95% CI: 1.123-1.682; P=0.02), and CSD (OR=1.880, 95% CI: 1.127-3.136; P=0.016), but a negative relationship with melanomas arising in non-CSD skin (OR=0.562, 95% CI: 0.392-0.805; P=0.002). The frequency of KIT mutations was associated negatively with melanomas located on the extremities. KIT mutations, which are critical in the genetic pathogenesis of melanomas, define a unique subtype of melanoma associated closely with older age, and acral, mucosal, or CSD sites, but not associated with any histological features or tumor stage. Although the KIT mutation rate is higher in White than Asian populations, no significant difference in clinical association with KIT mutations was detected between the two groups.