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The type 1 insulin‐like growth factor receptor is over‐expressed in bladder cancer
Author(s) -
Rochester Mark A.,
Patel Nilay,
Turney Benjamin W.,
Davies David R.,
Roberts Ian S.,
Crew Jeremy,
Protheroe Andrew,
Macaulay Valentine M.
Publication year - 2007
Publication title -
bju international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.773
H-Index - 148
eISSN - 1464-410X
pISSN - 1464-4096
DOI - 10.1111/j.1464-410x.2007.06931.x
Subject(s) - bladder cancer , insulin like growth factor 1 receptor , urothelium , insulin like growth factor receptor , receptor tyrosine kinase , pathology , immunostaining , urinary bladder , insulin like growth factor , biology , receptor , cancer , immunohistochemistry , growth factor , medicine
OBJECTIVE To analyse bladder cancer biopsies and investigate the pattern of expression of the type 1 insulin‐like growth factor receptor (IGF1R), a receptor tyrosine kinase that mediates tumour cell proliferation, motility and protection from apoptosis. MATERIALS AND METHODS Formalin‐fixed specimens of bladder cancer (40 whole‐mount, 80 cores on a tumour microarray) and normal bladder (15 samples) were stained immunohistochemically for the IGF1R. The IGF1R expression was also measured by quantitative reverse transcription‐polymerase chain reaction (Q‐RT‐PCR) on RNA extracted from fresh frozen bladder cancers (61) and benign bladder (12). RESULTS Of the 15 samples of normal bladder, 14 showed negligible (1+) or light (2+) IGF1R immunostaining. By contrast moderate (3+) or heavy (4+) staining for IGF1R was detected in 89 (74%) of the 120 samples of malignant urothelium. Q‐RT‐PCR showed significantly higher levels of steady‐state IGF1R mRNA in tumours (all cases, Ta–T4) than in normal bladder ( P < 0.05), indicating up‐regulation at the transcriptional level. This difference was particularly evident when comparing normal urothelium with superficial (Ta–T1) or invasive (T2–4) tumours; only the latter showed significant IGF1R over‐expression at the RNA level ( P < 0.05 vs normal bladder). CONCLUSION The IGF1R is up‐regulated in bladder cancer compared with non‐malignant bladder, and might contribute to a propensity for invasion.