In colorectal cancer (CRC), high expression of trefoil factor 3 (TFF3) is associated with tumor progression and reduced patient survival; however, bioinformatics analyses of public 'omics' databases show low TFF3 expression in CRCs as compared to normal tissues. Thus, we examined TFF3 expression in CRCs and matching normal tissues to evaluate its role in CRC progression. TFF3 gene expression was characterized using the bioinformatics portal UALCAN (http://ualcan.path.uab.edu). Tissue microarrays (TMAs) of archival CRC specimens (n=96) were immunostained with anti‑human TFF3 antibodies. Immunohistochemical (IHC) staining intensity was semi‑quantitatively scored. For this cohort, the median follow‑up was 5.4 years. Associations between clinical and pathological variables were determined using Chi‑square or Fisher's exact tests. Univariate disease‑free survival was estimated by the Kaplan‑Meier method. Omics data analyses by UALCAN showed downregulation of TFF3 expression in CRC relative to normal tissue at protein (χ2, P<0.0001) levels. There was a similar decreasing trend of TFF3 expression in the pathologic stages of the CRCs (RNA, χ2, P=0.88 and protein, χ2 P<0.0001). UALCAN data analysis showed that TFF3 exhibited 27% lower mRNA expression in tumors with mutant TP53 (P=0.007). Confirming the findings of omics analyses, IHC analysis of TMAs exhibited lower TFF3 expression in 95.6% (65 of 68) of the available normal‑tumor matching pairs (χ2, P<0.0001). There was no statistically significant association of tumor TFF3 expression with patient sex, race/ethnicity, tumor location within the colorectum, Tumor, Node, Metastasis (TNM) stage, lymph node metastasis, or surgical margins. However, low TFF3 IHC staining in tumor tissue was associated with histological grade (P=0.026). Kaplan‑Meier survival analysis showed no prognostic value of low TFF3 expression relative to those with high expression (log‑rank, P=0.605). Our findings demonstrate low expression of TFF3 in CRCs. Association between low TFF3 and histopathological features suggests involvement of this molecule in progression of CRC.
Keywords: TFF3; trefoil factor3; colorectal cancer; RNA expression; immunohistochemical expression.