Insulin-like growth factor 1 (IGF-1) and its receptor mRNA levels in breast cancer and adjacent non-neoplastic tissue

Anticancer Res. 2006 Jan-Feb;26(1A):167-73.

Abstract

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.

Materials and 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).

Discussion: 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.

MeSH terms

  • Antibodies, Monoclonal / chemistry
  • Breast Neoplasms / genetics
  • Breast Neoplasms / metabolism*
  • Humans
  • Immunohistochemistry
  • Insulin-Like Growth Factor I / biosynthesis*
  • Insulin-Like Growth Factor I / genetics
  • RNA, Messenger / biosynthesis*
  • RNA, Messenger / genetics
  • Receptor, IGF Type 1 / biosynthesis*
  • Receptor, IGF Type 1 / genetics
  • Receptor, IGF Type 1 / immunology
  • Reverse Transcriptase Polymerase Chain Reaction

Substances

  • Antibodies, Monoclonal
  • RNA, Messenger
  • Insulin-Like Growth Factor I
  • Receptor, IGF Type 1