Association of overexpression of TNF receptor superfamily members (CD40, BAFFR, LTβR and RANK) with favorable prognosis in patients with colorectal adenocarcinoma.

Abstract

e15516 Background: Numerous studies by our and other groups have highlighted the implication of NF-κB in colorectal cancer (CRC) through the deterioration of classical and alternative pathway signaling. The alternative pathway of NF-κB can be activated by members of TNF superfamily, such as lymphotoxin β (LTβ), tumor necrosis factor ligand superfamily member 5 (CD40L), B-cell activation factor (BAFF) and receptor activator of NF-κB ligand (RANKL). We have previously shown that alternative pathway of NF-κΒ is deteriorated in CRC. In the present study, we investigated the clinical significance of the aforementioned receptors in patients with CRC as well as their relation with effector transcription factors NF-κB2 and RELB. Methods: Gene expression of CD40, BAFFR, LT β R, RANK, NF- κ B2 and RELB, quantified by using real-time qRT-PCT and specific primers and probes, was assessed in 97 cancerous and 61 paired non-neoplastic tumor-adjacent formalin-fixed paraffin-embedded (FFPE) tissue specimens from CRC patients who were surgically managed in the University Hospital of Patras, Greece. Concurrently, we assessed protein expression of the same molecules by immunohistochemistry in the same cohort of patients. Both, mRNA and protein levels of the receptors were analyzed in association with clinicopathological parameters and clinical outcome of the patients in terms of time to disease progression. Results: Cytoplasmic expression of all molecules was higher in cancer compared to tumor-adjacent epithelial cells ( p= 0.047 for CD40, p= 0.007 for BAFFR, p< 0.001 for LTβR and p= 0.003 for RANK) and in stromal cells ( p< 0.001 for all molecules), while the reverse pattern (lower in neoplastic epithelial cells) was observed for nuclear expression ( p< 0.001 for all molecules). Similarly, mRNA levels of LTβR and RANK were higher in cancer compared to adjacent non-neoplastic tissues ( p= 0.019 and p= 0.037, respectively). Notably, patients with high mRNA levels of all studied receptors had significantly longer time to disease progression ( p= 0.026 for CD40, p= 0.023 for BAFFR, p= 0.027 for LTβR and p= 0.038 for RANK). In addition, mRNA levels of BAFFR, LTβR and RANK levels were higher in ulcerative tumors compared to polypoid tumors ( p= 0.002, p= 0.005 and p= 0.011, respectively). RELB mRNA levels were positively correlated with mRNA levels of CD40, BAFFR and LTβR in cancerous ( p< 0.001 for all molecules) and non-cancerous tissues (p < 0.001 for all molecules). Surprisingly, NF-κB2 mRNA levels were positively correlated with BAFFR and LTβR mRNA levels in malignant tissues, while in non-malignant tissues were positively correlated with all receptors’ mRNA levels ( p< 0.001 for all molecules). Conclusions: This study suggests a prognostic value for CD40, BAFFR, LTβR and RANK expression in patients with CRC and further supports the role of the alternative pathway of NF-κB in CRC.