EGF and lung adenocarcinoma: The internalization of 125I-EGF and 125I-225 mAb has been compared in A549 lung adenocarcinoma cells [53], and within approximately 15 min, the internal-to-surface ratio was found to plateau at values of 2.5 for 125I-EGF and 0.4 for 125I-225 mAb.