https://www.selleckchem.com/products/CP-690550.html Cutaneous side effects such as acneiform eruption, xerosis, and paronychia are frequently observed in patients undergoing treatment with epidermal growth factor receptor (EGFR) inhibitors for non-small cell lung cancer and other solid tumors. Interestingly, these side effects appear to positively correlate with length of remission, indicating that disruption of homeostatic EGFR signaling in the skin may serve as a marker of therapeutic EGFR inhibition in tumors. We report the case of a woman with metastatic lung cancer in remission being treated with the EGFR inhibitor, erlotinib, who experienced numerous commonly occurring adverse cutaneous reactions early in her treatment, and after two years of treatment developed eruptive nevi as well as a nevoid melanoma. Changes in pigmented lesions and the development of melanoma have been described during treatment with the BRAF inhibitor, vemurafenib, and are believed to relate to paradoxical activation of BRAF and the MAPK pathway. We speculate that a similar mechanism may occur during treatment with EGFR inhibitors. Therefore, thorough skin examinations are essential for patients undergoing long term treatment with erlotinib.Chronic myelogenous leukemia (CML) is characterized by a reciprocal translocation between the long arms of chromosomes 9 and 22 leading to the formation of a constitutively active tyrosine kinase. Tyrosine kinase inhibitors (TKIs) are the treatment of choice for patients diagnosed with CML and have many associated side effects including the rarely-reported eruption of squamous cell carcinomas (SCCs). Herein, we report a patient with CML who presented with sudden onset of multiple scaly lesions on his legs and trunk after beginning treatment with nilotinib, a novel TKI. Six biopsies were performed at his initial presentation and four of these lesions were confirmed to be keratoacanthoma-type SCCs. One month later, the patient reported the development