Since falls in ATP and/or MMP have been reported in SK-N-SH neuroblastoma cells and human primary foreskin cells treated with concentrations of formaldehyde similar to those used in this study [42,43], we examined whether any of the effects of C13 to activate AMPK could be explained by the generation in treated cells of formaldehyde, instead of or in addition to the known effects of the other product of cellular C13 metabolism, the AMP analogue C2. This evidence concerns the gene PRKAA1 and neuroblastoma.