Exploiting interleukin 6 in multicentric Castleman's disease

910 www.thelancet.com/oncology Vol 15 August 2014 be equally potent across every resistance mechanism. Defi ning how resistance is acquired with the BRAF and MEK inhibitor combination will help resolve this conundrum. Research is needed to ascertain whether early use of a combination of BRAF and MEK inhibitors— while disease burden and permutations of genomic alterations brought about by intratumour heterogeneity are limited—is the best strategy to forestall resistance, or whether a sequential approach with appropriate patient selection could result in equivalent effi cacy.