Determination of follistatin-like protein 1 expression in colorectal cancer and its association with clinical outcomes.

Background: Follistatin-like protein 1 (FSTL1) has been demonstrated to play a controversial role in cancer. In this study, we aimed to investigate the expression of FSTL1 and its characteristics in patients with colorectal cancer (CRC).
Methods: Gene expression microarray assays in 30 CRC patients and a real-time quantitative polymerase chain reaction (RT-qPCR) of 22 patients were performed to compare the mRNA level of FSTL1 in tumor lesions and paired normal tissues. Also, 332 consecutive patients with pathologically confirmed CRC were selected to detect FSTL1 expression by using immunohistochemistry (IHC). Enzyme-linked immunosorbent assay (ELISA) was also applied to determine the serum level of FSTL1 in 60 CRC patients, as well as 34 healthy donors.
Results: Gene expression microarray assays and RT-qPCR in CRC tissues, as well as ELISA in the serum all, revealed that the expression level of FSTL1 was higher in cancer tissue of CRC patients compared with paired normal tissue or healthy donors. The IHC results suggested that FSTL1 was also higher in tumor tissues than in its normal counterparts, however interestingly, a narrow scan focusing on the stromal region indicated that FSTL1 was significantly higher in normal tissues than in cancerous tissues. Besides, higher FSTL1 expression in cancer tissue, as well as lower FSTL1 expression in cancer stroma, both correlated with a worse prognosis, and the latter was an independent prognostic factor.
Conclusions: Our results provide novel insight into the role of FSTL1 in CRC, and it might be an essential factor in CRC development.
Competing Interests: Conflicts of Interest: The authors have no conflicts of interest to declare.
(2019 Annals of Translational Medicine. All rights reserved.)