We showed the changes in residual tumors (NSCLC cell line- or patient-derived tumor xenografts in immune-compromised NOD/SCID mice or LLC allografts in immune-competent C57BL/6 mice) after chemotherapy at a pre-defined time point and demonstrated that the ATF6-mediated production of EGF in SCCs is one of the mechanisms responsible for tumor relapse. Here, EGF is linked to neoplasm.