bFGF could be a biomarker of malignancy in RS 3 PE syndrome: an ambispective single-center cohort analysis of 51 patients

Objectives Remitting seronegative symmetrical synovitis with pitting edema (RS 3 PE) is a rare inflammatory arthritis, with a higher incidence of malignancy. The aim of this study is to identify biomarkers for predicting malignancy in RS 3 PE. Methods A total of 51 patients with RS 3 PE from September 2007 to May 2019 were retrospectively reviewed and followed for up to 5 years, with 15 patients with osteoarthritis (OA) and 14 patients with elderly-onset rheumatoid arthritis (EORA) as disease controls. Serum levels of angiogenesis cytokines were measured by electrochemiluminescent immunoassay and Luminex Human Magnetic Assay. Clinical data and laboratory parameters were analyzed to identify risk factors for malignancy. Results A total of forty-eight RS 3 PE patients (94.1%) were available with follow-up data; 8 patients (16.7%) were diagnosed with malignancy, of which 6 patients were hematological tumor; and 2 patients were solid tumors. Serum levels of basic fibroblast growth factor (bFGF) were exclusively higher in RS 3 PE patients with malignancy [14.21 (7.52, 23.18) ng/mL] than RS 3 PE patients without malignancy [4.32 (2.88, 7.42) ng/mL], OA [3.20 (2.20, 5.30) ng/mL], and EORA [3.20 (2.20, 5.30) ng/mL]. The optimal cut-off value of bFGF for malignancy was 10ng/mL in RS 3 PE. Logistic regression analysis indicated that elevation of bFGF was a risk factor for malignancy in RS 3 PE. Conclusions This study indicated that bFGF was elevated in RS 3 PE patients with malignancy and could serve as a biomarker for predicting paraneoplastic RS 3 PE.