Mutational heterogeneity can contribute to therapeutic resistance in solid cancers. In melanoma, the frequencies of intertumoral and intratumoral heterogeneity are controversial. We examined mutational heterogeneity within individual patients with melanoma using multiplatform analysis of commonly mutated driver and nonpassenger genes. We analyzed paired primary and metastatic tumors from 60 patients and multiple metastatic tumors from 39 patients whose primary tumors were unavailable (n = 271 tumors). We used a combination of multiplex SNaPshot assays, Sanger sequencing, mutation-specific PCR, or droplet digital PCR to determine the presence of BRAF^V600, NRAS^Q61, TERT^–124C>T, and TERT^–146C>T mutations. Mutations were detected in BRAF (39%), NRAS (21%), and/or TERT (78%). Thirteen patients had TERT^mutant discordant tumors; seven of these had a single tumor with both TERT^–124C>T and TERT^–146C>T mutations present at different allele frequencies. Two patients had both BRAF and NRAS mutations; one had different tumors and the other had a single tumor with both mutations. One patient with a BRAF^mutant primary lacked mutant BRAF in at least one of their metastases. Overall, we identified mutational heterogeneity in 18 of 99 patients (18%). These results suggest that some primary melanomas may be composed of subclones with differing mutational profiles. Such heterogeneity may be relevant to treatment responses and survival outcomes.

突变异质性可能导致实体癌的治疗耐药性。在黑色素瘤中，肿瘤间和肿瘤内异质性的频率存在争议。我们使用常见突变驱动基因和非乘客基因的多平台分析来检查个体黑色素瘤患者的突变异质性。我们分析了 60 名患者的配对原发性和转移性肿瘤以及 39 名原发性肿瘤无法获得的患者的多个转移性肿瘤（n = 271 个肿瘤）。我们结合使用多重 SNaPshot 测定、Sanger 测序、突变特异性 PCR 或液滴数字 PCR 来确定BRAF ^V600、NRAS ^Q61、TERT ^–124C>T和TERT ^–146C>T突变的存在。在BRAF (39%)、NRAS (21%) 和/或TERT (78%)中检测到突变。13 名患者患有TERT^突变不一致肿瘤；其中七个具有单一肿瘤，同时具有不同等位基因频率的TERT ^{– 124C>T}和TERT ^{– 146C>T突变。}两名患者同时患有BRAF和NRAS突变；一个有不同的肿瘤，另一个有一个带有两种突变的肿瘤。一名患有BRAF^突变原发灶的患者至少在其一个转移灶中缺乏突变BRAF 。总体而言，我们在 99 名患者中的 18 名（18%）中发现了突变异质性。这些结果表明，一些原发性黑色素瘤可能由具有不同突变谱的亚克隆组成。这种异质性可能与治疗反应和生存结果有关。