Fig 1: Macrophage infiltration is a hallmark of CI-deficient tumor microenvironment. a Flow cytometry analysis of innate immune system populations in 143B (n = 4, df = 6) and HCT (n = 5, df = 8) tumors. The contribution of macrophages (F4/80 +) [t(143B) = 2.8, t(HCT) = 2.8], neutrophils (Lys6G +) [t(143B, data were log-transformed) = 5], dendritic cells (CD11c + F4/80-) and natural killer cells (CD49b +) is shown at day 30 post injection in ICRF nude mice. Data are mean + s.e.m. b Macrophage to cancer cell ratio in 143B (n = 4, df = 6, t = 3.21) and HCT (n = 5, df = 8, t = 4.834) xenografts. Data are mean + s.e.m. Representative dot-plots display contribution of macrophages (F4/80 +, in blue) and neutrophils (Ly6G +, in red) among 100,000 acquired events (SSC-A/FSC-A plots) and their relative amount among CD45 + population (F4/80/Ly6G plots). All other cell populations are represented in gray. The gates indicate population percentages. c Flow cytometry analysis of undifferentiated (CD11b + Ly6C +) and differentiated (CD11b + Ly6C-) monocytes in 143B (n = 4, df = 6, t = 4.213) and HCT (n = 3, df = 4, t = 2.674) xenografts at day 30 post injection in ICRF nude mice. Representative contour-plots are shown. The gates indicate population percentages. Data are mean + s.e.m. d The number of macrophages (F4/80 +) infiltrating tumor tissue counted per field of view (FOV) in xenografts at day 10 [143B (n = 3, df = 4, t = 8), HCT (n = 3, df = 4, t = 9)] and at day 30 [143B (n = 4, df = 6, t = 5.376), HCT (n = 3, df = 3, t = 3.201)] post injection. Representative images of immunohistochemistry analysis for macrophage marker F4/80 in xenografts are shown. Dashed lines delineate the tumor margin. Scale bars: 50 µm. Data are mean + s.e.m. e Representative image of immunofluorescent staining of the SMA + microenvironment component in HCT xenografts. Dashed lines delineate the tumor margin. The arrows indicate the collective CAF formations. Scale bars: 50 µm. In each panel, statistical significance is specified with asterisks (*p < 0.05, **p < 0.01, ***p < 0.001)