Insulin-like growth factor 1 (IGF-1) and its receptor mRNA levels in breast cancer and adjacent non-neoplastic tissue.
Previous studies investigating the insulin-like growth factor 1 receptor (IGF-1R) expression in breast cancer tissue and adjacent non-neoplastic breast tissue (ANCT) have produced conflicting results. The IGF-1 and IGF-1R expression in pairs of breast cancer tissue and ANCT were investigated using RT-PCR and immunohistochemistry. The results of both methods were compared.


METHODS
IGF-1 and IGF-1R mRNA from 31 specimen pairs were estimated using RT-PCR. Immunohistochemistry for IGF-1R was carried out on 20 specimen pairs and the strength of staining was scored.


RESULTS
The mean relative IGF-1 mRNA level was lower in the cancerous tissue (mean 0.450 +/- 0.206) than in the ANCT (mean 0.632 +/- 0.384) (paired t-test, p = 0.001). There was no measurable difference in relative IGF-1R mRNA levels in the cancerous tissue (mean 0.146 +/- 0.08) and the ANCT (mean 0.14608 +/- 0.108) (paired t-test, p = 0.807). Using immunohistochemistry, there was no statistical difference (paired t-test, p = 0.910) in IGF-1R staining scores between cancer (mean 1.93) and ANCT (mean 1.90). The comparison between the two methodologies showed no correlation (Pearson's Correlation Coefficient = -0.393).


CONCLUSIONS
It can be concluded that IGF-1 expression is lower in cancerous tissue, thus supporting a paracrine relationship between cancerous tissue and ANCT, which may be useful in the prevention, diagnosis and treatment of breast cancer. There was no difference in the expression of the IGF-1 receptor in both types of tissue, as proven by RT-PCR and immunohistochemistty. Conflicting results in previous studies may be due to the different methods used to measure IGF-1R expression.
Chong
Y M
YM
Department of Breast Surgery, St. George's Hospital and Medical School, University of London, London SW17 0RE, UK.
Williams
S L J
SL
Elkak
A
A
Sharma
A K
AK
Mokbel
K
K
D000911:Antibodies, Monoclonal / Q000737:chemistry; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007150:Immunohistochemistry; D007334:Insulin-Like Growth Factor I / Q000096:biosynthesis* / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis* / Q000235:genetics; D017526:Receptor, IGF Type 1 / Q000096:biosynthesis* / Q000235:genetics / Q000276:immunology; D020133:Reverse Transcriptase Polymerase Chain Reaction
D000911:Antibodies, Monoclonal; D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I; D017526:Receptor, IGF Type 1