Fig. 2.

Immunohistological staining of distinct CDKs and P-Rb activation in human lung specimen. Representative images of serial sections from healthy (n = 5) and IPAH-patient derived lungs (n = 5) analyzed for CDK2 (a), CDK4 (b), and CDK6 (c), with corresponding IHC for P-Rb protein and its downstream target gene and common proliferation marker PCNA (proliferation cell nuclear antigen). Cellular identity was visualized by antibodies against α-SMA (alpha-smooth muscle actin) and vWF (von-Willebrand factor). Images were taken at 400-fold magnification with a scale bar of 20 µm