OBJECTIVETo investigate the expression of follistatin-like protein 1 (FSTL-1) in bone metastasis of prostate cancer (BMPC), the correlation of serum FSTL-1 with the chronic inflammatory factor interleukin-6 (IL-6) and bone morphogenetic protein 6 (BMP6) , and the clinical application value of serum FSTL-1 in BMPC.

METHODSUsing ELISA, we measured the expression levels of serum FSTL-1, IL-6, and BMP6 in 35 patients with BMPC and another 30 with benign prostatic hyperplasia (BPH) and performed correlation analysis on the data obtained.

RESULTSCompared with the BPH controls, the BMPC patients showed a significantly decreased expression of serum FSTL-1 ([34.45 ± 12.35] μg/L vs [20.23 ± 8.69] μg/L, P < 0.01) and increased levels of IL-6 ([11.21 ± 8.62] μg/L vs [23.56 ± 20.12] μg/L, P < 0.05) and BMP6 ([293.50 ± 39.72] μg/L vs [428.30 ± 178.40] μg/L, P < 0.05). There was a significant negative correlation between the level of serum FSTL-1 and those of IL-6 and BMP6 in the BMPC patients, with correlation coefficients of -0.971 and -0.972, respectively (P < 0.05).

CONCLUSIONThe expression of serum FSTL-1 decreases in patients with bone metastasis of prostate cancer, and it is correlated with the levels of inflammatory factor and cell transformation factor. This finding offers a novel biological marker for the development and progression of prostate cancer as well as a new biological target factor for its intervention.