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Insulin‐like growth factor binding protein‐related protein 1 (IGFBP‐rP1/mac 25) is reduced in human prostate cancer and is inversely related to tumor volume and proliferation index in Lucap 23.12 xenografts
Author(s) -
Tennant Marie K.,
Vessella Robert L.,
Sprenger Cynthia C.,
Sikes Robert A.,
Hwa Vivian,
Baker Laura D.,
Plymate Stephen R.
Publication year - 2003
Publication title -
the prostate
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.295
H-Index - 123
eISSN - 1097-0045
pISSN - 0270-4137
DOI - 10.1002/pros.10223
Subject(s) - prostate , prostate cancer , immunohistochemistry , medicine , cancer research , staining , cancer , epithelium , growth factor , pathology , receptor
BACKGROUND In the prostate, insulin‐like growth factor binding protein‐related protein‐1 (IGFBP‐rP1/mac 25) appears to be decreased in cancer. Likewise, mice injected with prostate cells over‐expressing IGFBP‐rP1/mac 25 showed decreased tumor formation and tumor volume. METHODS Immunohistochemistry was used to determine the presence of IGFBP‐rP1/mac 25 in human prostate tissue and in LuCaP 23.12 prostate cancer xenografts. RESULTS Immunoreactivity for IGFBP‐rP1/mac 25 was detected in the cytoplasm and nuclei of benign prostate epithelium. Cancer cells also stained but the level of intensity was less than that observed in benign epithelium ( P < 0.05). Within the stroma, peripheral nerves, and endothelial vessels reacted with IGFBP‐rP1/mac 25 antibodies. IGFBP‐rP1/mac 25 was also observed in the nuclei of LuCaP 23.12 cells. LuCaP xenografts with smaller tumor volumes demonstrated more staining, and larger tumor volumes had less staining ( P = 0.0033, R = 0.610). There was also a significant inverse correlation between IGFBP‐rP1/mac 25 levels in LuCaP 23.12 cells and the proliferative index, measured by percent of cells staining for 5‐bromo‐2′‐deoxyuridine (Br‐dU) ( P = 0.0045, R = 0.594). CONCLUSIONS IGFBP‐rP1/mac 25 is present in normal prostate epithelium and is decreased in human prostate malignancy and higher IGFBP‐rP1/mac 25 levels are associated with reduced tumor growth. Prostate 56: 115–122, 2003. © 2003 Wiley‐Liss, Inc.