IGF1R and IR expression are enhanced in primary human CLL cells compared with healthy B cells. (A) Healthy B cells or CLL B cells purified from freshly isolated or freeze-thawed PBMCs from CLL patient samples were stained for CD221 (IGF1R; left bar graph) and CD220 (IR; right bar graph), and expression was determined by flow cytometry (n = 10). (B) Healthy B cells or CLL B cells purified from freshly isolated or freeze-thawed PBMCs from CLL patient samples were lysed and analyzed for receptor expression by western blot analysis. Left: A representative example is shown. Right: Densitometric analysis of all samples (n = 20). (C) CLL B cells purified from freshly isolated or freeze-thawed PBMCs of different prognostic CLL subgroups with different genetic aberrations were lysed and compared for receptor expression by western blot analysis. Left: A representative example is shown. Right: Densitometric analysis of all samples (n = 12; mean ± SEM). (D) Healthy B cells or CLL B cells, NLCs, CD14⁺ cells, or T cells purified from freshly isolated or freeze-thawed PBMCs from CLL patient samples were lysed and analyzed for IGF-1 expression by western blot analysis. The densitometric analysis is derived from 12 different CLL samples (mean ± SEM). (E) Lymph nodes from healthy donors, CLL patients, breast cancer and prostate tissue underwent immunohistochemistry using a polyclonal rabbit antibody against IGF1R. One representative staining is shown for each group.