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.

Tumour budding in colorectal cancer: what do we know and what can we do?

Budding is a process during which individual or small clusters of up to five tumour cells detach from the main tumour mass and invade into the surrounding stroma. In colorectal cancer, this feature is observed in 20-40% of cases and is associated with lymphovascular invasion, lymph node and distant metastases, and poor prognosis. A variety of scoring systems for budding have been proposed but so far a gold standard is lacking, hampering implementation of a budding score in guidelines for pathological examination of colorectal cancer. Furthermore, little is known about the mechanisms which cause tumour cells to detach from the main tumour mass and obtain increased invasive potential. In this review, we present an overview of tumour budding including its definition, scoring systems, prognostic relevance and biological mechanisms involved.

KRAS, NRAS, BRAF mutation comparison of endoscopic and surgically removed primary CRC paired samples: is endoscopy biopsy material adequate for molecular evaluation?

Background:

An everyday clinical practice dilemma in the 20–30% of metastatic colorectal cancer (CRC) patients that have not been operated on their primary tumour, is, under which specific histopathology and molecular circumstances, an endoscopic biopsy could be considered adequate to provide a representative RAS/BRAF molecular status to guide treatment.

Methods:

A consecutive series of 193 paired biopsy and primary CRC tumour samples between August 2008 and 2010 available in the Department of Pathology archives, University Hospitals, KU Leuven were retrieved. For a pair to be included, in the endoscopic biopsy, 20% of invasive adenocarcinoma cells should be present and enough slides to yield an extracted DNA concentration of ⩾5 ng μl⁻¹, and no <2 ng μl⁻¹ should be available for cutting. Exons 2–4 KRAS/NRAS, BRAF, PIK3CA molecular evaluation was performed with RT–PCR and Sequenom.

Results:

From 165 deemed adequate by the pathologist pairs, 85 (51.5%) were concordantly mutated in at least one of the tested genes, 70 (42.5%) were wt and 10 (6%) were discordant, harbouring a mutation in the primary and not in the endoscopic biopsy. In the re-evaluation, when more slides were cut per discordant pair, mutational status changed in two of the six discordantly KRAS-mutated pairs. A strong strength of agreement for both runs was observed (Cohen's kappa, k=0.877, P<0.001 and k=0.901, P<0.001, respectively) between the surgically acquired and the endoscopic biopsy specimens' evaluation.

Conclusions:

Based on our results, an endoscopic biopsy could provide an accurate mutational profile and become a justified alternative to a surgically removed primary tumour specimen, as long as specific histopathology criteria are met.