XXXX -V600 Mutation Heterogeneity in Primary and @entity320 : A Study With Pyrosequencing and Immunohistochemistry.

@entity1 @entity17330 @entity5 @entity16232 @entity8554 @entity72350 @entity43051 @entity3 @entity817 @entity320
BACKGROUND: The @entity817 -V600 mutation is the most common mutation in cutaneous @entity320 and is currently considered a target mutation when planning treatment for @entity320 @entity1 . Various techniques are used to determine the mutation status. The aim of this study was to determine the @entity817 -V600 mutation status in primary and metastatic foci of @entity320 cases and the consistency between the results of immunohistochemical and molecular methods. METHODS: A total of 48 primary or metastatic cases were included in the study. Pyrosequencing was used as the molecular method and the VE1 antibody for immunohistochemical evaluation when determining the @entity817 -V600 mutation. RESULTS: The @entity817 -V600 mutation was found in 75 of the 96 @entity5 (78.1%) from the 48 cases. @entity8554 and @entity16232 were present in 60 and 10 @entity5 , respectively, whereas @entity17330 and @entity72350 were present in 2 @entity5 and @entity43051 in 1 @entity5 . There was no mutation in 5 metastases (12.8%) of the 39 cases with a V600 mutation in the @entity5 and no mutation in the @entity5 of 2 of the 36 cases (5.6%) with the V600 mutation in the @entity3 . Fifty-six @entity5 were immunohistochemically positive where a @entity8554 mutation was detected with pyrosequencing. @entity5 (n = 20) and @entity5 with non- @entity8554 mutations (n = 15) on pyrosequencing were immunonegative with VE1. The sensitivity and specificity of immunohistochemistry were 93.3% and 97.2%, respectively. CONCLUSIONS: In conclusion, @entity817 -V600 mutation inconsistencies of up to 14.5% can be seen between the primary and metastatic foci in @entity320 cases. These findings should be taken into account when planning targeted therapy and deciding on treatment responsiveness/unresponsiveness. An immunohistochemical method can be used as the first step to detect a @entity817 -V600 mutation but additional molecular methods should be used when immunohistochemistry results are negative.
