The latter is illustrated by the differences in the prevalence of gsp alpha mutations among Caucasians,19,20 Asian21 and Mexican22 patients with acromegaly and the notion that tumours that harbour such molecular changes are less invasive and respond better to octreotide.20 After 48 weeks of treatment, 44% of our patients had achieved a safe GH level, 34% had normalized their IGF-1 levels and 25% achieved both criteria of biochemical control. Here, IGF1 is linked to acromegaly.