MAPK1 and neoplasm: Of note, MEK inhibitors are not considered standard treatment for the treatment of ACPs which do not typically harbor BRAF V600E mutations unlike PCPs more commonly seen in adults.11 However, recent data suggests that ACPs do show evidence of MEK/ERK pathway activation, similar to the immunohistochemistry findings in our patient’s tumor tissue.3,7 Previous authors have shown that MEK inhibition may be effective in the management of ACPs3,6,7 and a phase II trial of the MEK inhibitor binimetinib is currently underway (NCT05286788).