SIRPA and neoplasm: To address this deficit, we created a 16-gene signature depicting TREM1 molecular and ligand secretion profile based on TREM1 myeloid cluster marker genes from four naïve human BCCs, two of which had a higher abundance of BIT tumor epithelial cells and two of which had a lower abundance of BIT tumor epithelial cells (Fig. 5a, Supplementary Fig. 4f, Supplementary Data 4).