Expression of FOXP1 and Colorectal Cancer Prognosis.

Background: Forkhead box gene P1 (FOXP1) has proven to be a valuable prognostic biomarker in lymphomas, but little is known about this gene in colorectal cancer (CRC).

Objectives: To investigate the expression of FOXP1 in CRC and its potential associations with outcome in CRC.

Methods: We studied the expression pattern of FOXP1 retrospectively via immunohistochemistry in a series of 165 - CRC cases. Fluorescent in situ hybridization and RNA sequencing on FOXP1 knockdown cell lines were performed to investigate the mechanism of action and target genes of FOXP1.

Results: Complete loss of nuclear FOXP1 expression was observed in 11.5% of the subjects. A total of 70.9% of subjects showed a heterogeneous FOXP1 expression pattern, and 17.6% of them had high FOXP1 expression. Impaired expression of FOXP1 was significantly correlated with reduced survival rates by multivariate analysis (P = .004). We found no chromosomal aberrations involving FOXP1 in individuals with FOXP1 negativity via immunohistochemical testing. RNA sequencing revealed that genes involved in inflammation and cell proliferation were differentially expressed after FOXP1 knockdown.

Conclusions: In our case series, loss of FOXP1 was associated with reduced survival rates in CRC tissue. Also, FOXP1 affects proliferation and inflammatory reaction in colorectal neoplasia.