This is based on the facts that: (1) the activity levels of p38 and ROCK1 are repressed in the iWAT of the GPR81−/− tumour-bearing mice; (2) lactate-induced p38 activation and subsequent UCP1 upregulation are profoundly suppressed by inhibition of RhoA/ROCK1; and (3) ablation of UCP1 ameliorates body weight loss and adipose and muscle remodelling induced by LLC tumours. The gene discussed is MAPK1; the disease is neoplasm.