PEAK1 and neoplasm: More recently, Hoover et al. compared RNA expression profiles of orthotopic and flank tumors, also using a xenograft model with human cell line injections (BxPC3 and FG) and patient-derived PDAC tissue, and found significant differences in the expression of PEAK1 and MST1R, both genes involved in PDAC pathogenesis, based on tumor location (Hoover et al., 2017).