Histological Characterization and Differentiation of Rash From Other Epidermal Growth Factor Receptor (EGFR) Inhibitors

Epidermal growth factor (EGF) and its receptor, the EGFR, are known to be key drivers in cellular proliferation and survival. Malignant tumors result from uncontrolled cell proliferation. The use of drugs which target the EGF receptor has offered patients with non-small cell lung cancer, pancreatic cancer, head and neck cancer, and colorectal cancer additional targeted anti-cancer therapy in addition to their chemotherapeutic regimens. As a result of increased use of these EGFR inhibitors, adverse events have emerged involving the skin, hair, nails and eyes. While the EGFR inhibitors block the signal transduction that interfere with cellular proliferation and survival of cancerous cells, they also affect the normal EGF function in the skin (papulopustular rash), hair, and nails. In this study, we seek to histologically characterize the papulopustular rash in patients who have been treated with lapatinib and compare our findings with those associated with three other EGFRIs, cetuximab, erlotinib and panitumumab.