Eighty breast cancer specimens were examined for insulin-like growth factor binding protein (IGFBP) expression by ligand blotting. Five distinct IGFBP species were found: a doublet at 48 and 44 kDa was IGFBP-3, the 34-kDa band was IGFBP-2, and a band at 24 kDa was IGFBP-4. A 32-kDa band was compatible with the migration position reported for IGFBP-5. IGFBP-3 was inversely correlated with ER expression, while IGFBP-4 was positively correlated with both ER and PgR. IGFBP-4 was also inversely correlated with S-phase fraction. Thus, IGFBP expression correlates with other parameters of breast cancer biology and may play a role in regulating tumor growth.
Bibliographical noteFunding Information:
Douglas Yee is a Pew Scholar in the Biomedical Sciencesa nd recipient of an NIH Research Career Development Award. This work was supported by grants R29 CA52592 and PO1 CA30195 and a cancer center support grant to the Cancer Therapy and Research Center. Jose A. Figueroa is supported by an NRSA training grant, CA09434.
- Breast cancer
- Estrogen receptor
- Insulin-like growth factor binding proteins
- Progesterone receptor
- S-phase fraction