Insulin-like growth factor binding protein expression in human small cell lung cancer cell lines.

Insulin-like growth factor binding proteins (IGF-BP) are secreted by several human small cell lung cancer cell lines (SCLC). In order to identify the IGF-BPs from SCLC cell lines the RNA from 10 different SCLC cell lines was analyzed by Northern blot analysis with the probes for three different IGF-BPs, IGFBP-1, IGFBP-2, and IGFBP-3. No hybridization signal could be detected with the probes encoding for IGFBP-1 and IGFBP-3. The hybridization with different IGFBP-2-specific oligodeoxynucleotide probes and with the corresponding full-length cDNA showed that all SCLC cell lines which secreted IGF-BPs express IGFBP-2.