Here, it is demonstrated that treating tumor cells with a peptide that replicates the amino acid sequence in Insig1/2 loop 1, which is the region where Insig1/2 interacts with AKT‐phosphorylated phosphoenolpyruvate carboxykinase 1 (PCK1), inhibits the IGF1‐induced interaction between PCK1 and Insig1/2. This evidence concerns the gene PCK1 and neoplasm.