To begin to query whether PAQR8 might function as a ceramidase, we analyzed the sphingolipidome of Paqr8-OE and Paqr8-KO Her2-dependent primary tumor cells 72 h after Her2 downregulation using liquid chromatography-high resolution mass spectrometry (LC-HRMS). The gene discussed is ERBB2; the disease is neoplasm.