Expression of basic fibroblast growth factor, FGFR1 and FGFR2 in normal and malignant human breast, and comparison with other normal tissues

Abstract

Summary The expression of basic fibroblast growth factor (bFGF) and two of its receptors, FGFR1 and FGFR2, was detected using the polymerase chain reaction, and quantified by comparison to the relative amount of product obtained following co-amplification of the ubiquitous glyceraldehyde phosphate dehydrogenase transcript. Varying levels were found in the vast majority of both cancer and non-malignant breast biopsies as well as in samples of several other normal human tissues. Significantly less bFGF was present in cancers (P< 0.0001). Similarly, FGFR2 product was also much less in cancer tissues (P = 0.0078), as was FGFR1 (P = 0.002). FGFR1 levels in cancers tended to be higher in those which were oestrogen receptor positive (P<0.06). Amplification of different coding regions showed evidence of variant forms of FGFR1 RNA. Cancers appeared to have a significantly greater proportion of PCR product corresponding to the region between the third immunoglobulin like domain and the tyrosine kinase domain (P = 0.046). Differential expression was observed in breast cell lines, with bFGF in the normal derived HBL100, HBR SVI.6.1 and 184A1 but little or none in ZR-.75-1, MCF-7, T47D and MDA-MB-231. FGFR1 was present in most of these but FGFR2 was absent from T47D, MDA-MB-231 and HBL100. ZR-75-1 cells had a marked preponderance of FGFRI variants lacking part of the coding sequence.Aberrant receptor processing may provide clues concerning the role of FGF's and their potential involvement in malignancy.

Down-regulation of a novel form of fibroblast growth factor receptor 1 in human breast cancer

“…Our results show that the FGFR-1 mRNA previously described in breast cell lines and human breast cancers (Lehtola et al, 1992;Luqmani et al, 1992;Luqmani et al, 1995;Penault-Llorca et al, 1995) does get translated into protein. It has previously been shown that the predominant form of FGFR-1 mRNA transcribed is the 5-form with the a-form present as a minority species (Luqmani et al, 1995;Penault-Llorca et al, 1995).…”

“…In the case of separated cells from reduction mammoplasty tissue, mRNA was extracted from 2.5 million epithelial or myoepithelial cells using the Dynabead mRNA direct protocol (Dynal). Reverse transcription was performed as described previously (Luqmani et al, 1992), using 2 jig of RNA and 500 ng of the random primer pdN6.…”

“…Semiquantitative RT-PCR to investigate expression levels of FGFR1 was carried out using a method described previously (Luqmani et al, 1992). cDNA was amplified using 1 unit of Taq polymerase in 100 ,ul containing 200 ng of the primers 5'-CCTCT-TCTGGGCTGTGCT-3' and 5'-TC l 1 CTGGGGATGTCC-3' for FGFR-1 cDNA and primers 5'-CATCTCTTGCTCGAAGA-AGTCCA-3' and 5'-ATCATGTl 7GAGACCTTCAA-3' for actin.…”

“…However, if FGFR-1 mRNA is present in significant quantifies in breast fibroblasts, FGFR-1 would be likely to be present, adding credence to the FGFR-1 variants in human breast 1425 106-kDa band being an isoform of FGFR-1. We used a semiquantitative RT-PCR technique that has been described in detail previously (Luqmani et al, 1992) …”

Breast cancer genome-wide association studies: there is strength in numbers

“…Overexpression of FGFR2, one of the common low-penetrance susceptibility genes, is observed in breast tumor tissues (Adnane et al, 1991) and in BC cell lines (Tannheimer et al, 2000). Its expression is associate with ER þ tumors (Luqmani et al, 1992), suggesting a hormone-dependent action of this gene. Recently, gene expression studies have shown increasing FGFR2 expression levels associated with the rare homozygote genotype and functional studies identified the OCT1/ RUNX2-binding site as the main determinant of the increased expression levels (Meyer et al, 2008).…”