PRKAA1 and neoplasm: While it has previously been proposed that anti-tumour effects of metformin may at least partially be mediated through AMPK-independent pathways [66, 67], our finding that approximately 90% of metformin-regulated genes are not differentially expressed after AICAR treatment demonstrates that caution must be exercised in assigning any observed effects of metformin to activation of AMPK without further validation.