IL6 and neoplasm: Immune modulation is another antitumour mechanism of MEK inhibitors,26 as MEK inhibition was reported to reduce the secretion of IL-6, which is associated with BTC tumour growth.26–29 In this study, higher baseline concentrations of IL-6 were associated with worse prognosis, which is similar to the results from other studies regarding the prognostic value of IL-6.30,31 Furthermore, after the second cycle of treatment, patients with a larger increase were associated with worse prognosis.