Fig. 1.

Myeloid cells and ALDH1^Bright cells are prevalent in PC. a Flow cytometry performed on human PC samples (N = 11) and normal human pancreas (N = 4). Representative flow cytometry plot of normal human pancreas and PC tumor compares CD45⁺ infiltrate. Flow cytometry plots gating on CD45⁺ cells shows CD14⁺ and CD15⁺ infiltrate in the tumor. A significant population of CD14⁺ cells is HLA-DR^low/−. A representative flow plot shows 2.68 % CD45⁺ cells infiltrating the normal human pancreas (gating is performed using isotype control). b Immunofluorescent staining was performed on normal human pancreas samples (N = 5) and PC samples (N = 5). Representative immunofluorescent confocal images (×63) of normal human pancreas and PC stained for (CD11b, CD14), (CD11b, CD15). Green CD14 or CD15, red CD11b and blue Topro. c A histogram reporting percentages (average values) of the monocytic and granulocytic myeloid cells and T cells infiltrating the tumor as a percentage of total cells in PC tissue (N = 11) compared to normal human pancreas (N = 4). Granulocytes (normal pancreas (mean ± SD) = 1.87 ± 0.5 and PC = 14.6 ± 0.65, p value <0.05) and monocytes (normal = 1.3 ± 0.7 and PC = 12.4 ± 1.07, p value <0.05) are significantly increased in PC. d Upregulation of myelopoiesis in human PC; bone marrow specimens were collected from PC patients (N = 16) and age-matched healthy controls (N = 7); methylcellulose-based colony-forming unit assays were performed as described in “Materials and methods” section and were scored for the total number of myeloid colonies (CFU-GM) after 8 days. Bar graph depicts mean ± SEM and asterisk denotes statistically significant difference between the two groups p < 0.05 by Mann–Whitney test. e ALDH1 activity in human PC (N = 11); representative flow cytometry plot of human PC tumor gated on live EpCAM⁺ cells using Aldefluor assay. Immunofluorescent staining was performed on PC samples (N = 5) and normal human pancreas samples (N = 5). Representative immunofluorescence confocal images (×63) of normal human pancreas and PC stained for EpCAM, ALDH1 (green ALDH1, red EpCAM and blue Topro). Arrows point toward ducts expressing ALDH1 activity. f The CD14–CD8 ratio predicts PC patient survival. Automated analysis of CD14⁺ and CD8⁺ IHC reveals the relationship between leukocyte density and overall survival. The Kaplan–Meier estimate of overall survival comparing CD14^Hi/CD8^Low, CD14^Low/CD8^Low, CD14^Hi/CD8^Hi, and CD68^Low/CD8^High, is shown. Patients with predominant CD14⁺/CD8^Low infiltrate in the tumor had a significantly reduced overall survival compared to all other groups (denoted as CD14^Low/CD8^Low, CD14^Hi/CD8^Hi, and CD14^Low/CD8^Hi). There is a statistically significant difference between CD14^Hi/CD8^Low and CD14^Low/CD8^Hi, p value <0.001