G-CSF receptor expression in ovarian cancer

Recombinant human granulocyte colony-stimulating factor (rhG-CSF) is clinically used to overcome neutropenic periods during chemotherapy. In vitro studies using cell lines as a model system have recently suggested that G-CSF can promote ovarian cancer growth. The objective of this work is to determine whether tumor cells express G-CSF-receptors (G-CSFR). A set of ovarian tumor biopsies and ovarian cancer cell lines was analyzed by RT-PCR, immunohistochemistry and immunofluorescence. The presence of a 276 bp-amplicon (exon 8-10) obtained by RT-PCR showed that 12 out of 16 ovarian tumor biopsies and two out of four ovarian cancer cell lines expressed G-CSFR-mRNA. G-CSFR-protein was detected in tumor cells of the 12 biopsies that also contained G-CSFR-mRNA. A second 409 bp-amplicon (exon 17) obtained by RT-PCR from the variable C-terminal cytoplasmic region of G-CSFR could be amplified only in four out of 16 biopsies and in none of the ovarian cancer cell lines studied. The results presented here indicate that G-CSFR is frequently expressed in ovarian cancer cells. Moreover, the failure of RT-PCR amplification of the 409 bp-amplicon in samples that express G-CSFR-mRNA suggests that C-terminal truncated receptor forms are also expressed.