Our recent study showed that Sp1 is modified by c-Jun NH2-terminal protein kinase 1 (JNK1) in mitosis, phospho-Sp1 increases its protein stability, and that its presence in cancer cells is higher than that in primary noncancerous cells, indicating that phosphorylation of Sp1 plays an important role for its stability during mitosis (3). The gene discussed is SP1; the disease is cancer.