Clinicopathological significance of BTF3 expression in colorectal cancer

Basic transcription factor 3 (BTF3) is a general RNA polymerase II transcription factor and is also involved in apoptosis regulation. Increasing evidence shows that BTF3 is aberrantly expressed in several kinds of malignancies, but there is no study to analyze BTF3 expression in colorectal cancer (CRC) patients. Applying immunohistochemistry, we detected BTF3 in CRCs (n = 156), the corresponding distant (n = 42), adjacent normal mucosa (n = 96), lymph node metastases (n = 35), and analyzed its relationships with clinicopathological and biological variables. Our results showed that BTF3 staining significantly increased from distant or adjacent normal mucosa to primary CRCs (p < 0.0001) or metastases (p = 0.002 and p < 0.0001). BTF3 was higher in distal cancers than in proximal cancers (57 % vs. 39 %, p = 0.041). It also showed stronger staining in primary CRCs stage I and II than that in stage III and IV (64 % vs. 35 %, p = 0.0004), or metastases (64 % vs. 29 %, p = 0.004). Cancers with better differentiation had a higher expression than those with worse differentiation (56 % vs. 37 %, p = 0.031). There were positive correlations of BTF3 expression with nuclear factor kappa B (NF-κB), RAD50, MRE11, NBS1, and AEG-1 (p < 0.05). In conclusion, BTF3 overexpression may be an early event in CRC development and could be useful biomarker for the early stage of CRCs. BTF3 has positive correlations with NF-κB, RAD50, MRE11, NBS1 and AEG-1, and might influence complex signal pathways in CRC.