['Cancer cachexia is characterised by skeletal muscle wasting; however, potential for muscle anabolism in patients with advanced cancer is unproven.', 'Quantitative analysis of computed tomography images for loss/gain of muscle in cholangiocarcinoma patients receiving selumetinib (AZD6244; ARRY-142886) in a Phase II study, compared with a separate standard therapy group. Selumetinib is an inhibitor of mitogen-activated protein/extracellular signal-regulated kinase and of interleukin-6 secretion, a putative mediator of muscle wasting.', 'Overall, 84.2% of patients gained muscle after initiating selumetinib; mean overall gain of total lumbar muscle cross-sectional area was 13.6\u2009cm(2)/100 days (∼2.3\u2009kg on a whole-body basis). Cholangiocarcinoma patients who began standard treatment were markedly catabolic, with overall muscle loss of -7.3\u2009cm(2)/100 days (∼1.2\u2009kg) and by contrast only 16.7% of these patients gained muscle.'] Is skeletal muscle anabolism a side effect of therapy with the MEK inhibitor : selumetinib in patients with cholangiocarcinoma?