To directly investigate the ability of iaRNAHSF1 to inhibit MAPK activity in human cancer cells, we stimulated HeLa cells expressing the aptamer or the control RNA with the mitogen, epidermal growth factor (EGF), and examine the effects it had on the activation of the EGF receptor or MAPK signaling by collecting cells 10 minutes after treatment and assaying the samples by Western blotting. Here, EGF is linked to cancer.