Acidic fibroblast growth factor is progressively increased in the development of oesophageal glandular dysplasia and adenocarcinoma

Aims: To determine by immunohistochemistry and amplification of cDNA the relationship between fibroblast growth factor (FGF) expression and progressive changes in Barrett's oesophagus associated with oesophageal adenocarcinoma (OA). The FGFs are potent mitogens that possess angiogenic properties and the capability to regulate growth and differentiation of various cell types. They have also been implicated in the development and progression of numerous solid tumours, including some carcinomas of the aerodigestive tract, such as nasopharyngeal carcinoma and pancreatic adenocarcinoma. Material and results: We studied the expression of the two prototypic FGFs, acidic FGF (FGF-1) and basic FGF (FGF-2), in OA and OA precursor lesions, including intestinal metaplasia (IM), low-grade dysplasia (LGD) and high-grade dysplasia (HGD). Fresh tissue from 10 OAs and four associated HGDs was available for the determination of FGF-1 and FGF-2 mRNA expression accomplished by the PCR amplification of cDNA. Using immunohistochemistry, we studied the expression of the FGF-I and FGF-2 proteins in archival, paraffin-embedded tissue that was available from 17 oesophageal resection specimens that included OAs and OA precursor lesions. As compared to gastric fundic mucosal controls, OAs and HGDs showed significantly enhanced expression of FGF-1 mRNA and protein. IMs and LGDs showed significantly lesser degrees of FGF-1 immunoreactivity that were not increased over controls. In contrast, both the overall percentage of FGF-2-reactive OAs and the overall FGF-2 protein expression, assessed using an immunoreactivity score, are comparable to FGF-2 expression in controls. Conclusions: It appears that FGF-2 is ubiquitously expressed in OA and in normal oesophageal and gastric mucosa while significant: FGF-1 expression is essentially restricted to HGD and OA. Our data also suggest that FGF-1 is sequentially upregulated in the progression from metaplasia to dysplasia and adenocarcinoma.