Figure 2. Macrophages are found in close proximity to neoplastic lesions.

A. CD68-positive (brown cells) are found at high density within a few cell diameters of a human PDAC lesion. Inset, occasional CD68-positive macrophages are found immediately juxtaposed to PDAC cells. B. CD68-positive macrophages are also found at high density in human chronic pancreatitis but with less obvious proximity to ductal lesions. Inset, higher magnification of CD68-positive cells. C. In the Ptf1aCre; LSL-KrasG12D mouse without sHB-EGF overexpression, acinar-ductal metaplasias are observed in regions of F4/80-positive macrophage infiltration. Arrows, acini losing apical cytoplasm and forming lumena, characteristics of acinar-ductal metaplasia.