title: Investigation of serum clusterin as a suitable biomarker for canine multicentric lymphoma
Creators: name: McNaught, Katie Anne
Publisher: name: University of Glasgow
Year: 2020
Subjects: subject: canine, lymphoma, multicentric lymphoma, biomarkers, clusterin.

description: Lymphoma (LSA) is a malignant neoplasm which arises from a clonal proliferation of lymphoreticular cells (Vail et al., 2013). It is the most common canine haematopoietic neoplasm (Gavazza et al., 2009; Vail et al., 2013), and accounts for 7-24% of all canine malignancies (Greenlee et al., 1990; Dobson et al., 2002; Fournel-Fleury et al., 2002). Multiple blood and tissue biomarkers have been investigated regarding potential prognostic significance for canine LSA, however currently there is no single marker which has proven to be more reliable than the established parameters such as substage, immunophenotype and grade. Clusterin (CLU), also known as apolipoprotein J, is a heterodimeric glycoprotein which is widely expressed (Trougakos et al., 2002, 2004) throughout the body. CLU is important in tumorigenesis, apoptosis, and immunoregulation (Trougakos et al., 2002; Pucci et al., 2004; Shannan et al., 2006); its expression is regulated by cytokines and growth factors, and is increased in response to physiological stress (Trougakos et al., 2002, 2004; Shannan et al., 2006). In human medicine, CLU expression has been associated with various malignancies, including carcinoma, melanoma, colon, prostate and breast cancer (Saffer et al., 2002; Pucci et al., 2004; Shannan et al., 2006; Frazzi et al., 2011; Koltai, 2014). Cytoplasmic expression of CLU is also upregulated in cases of anaplastic large cell lymphoma and Hodgkin's lymphoma (HL) (Wellmann et al., 2000; Saffer et al., 2002; Shannan et al., 2006; Frazzi et al., 2011). A previous study of the canine serum proteome identified CLU in serum from a dog with high grade multicentric lymphoma (MLSA), and the absence of CLU in serum from healthy controls (Atherton et al., 2013a, 2013b). The objective of this current study was to determine whether CLU expression differed significantly between those dogs with MLSA and a healthy control population. It was hypothesised that serum CLU expression would be higher in dogs with MLSA in comparison to healthy controls and that serum CLU levels would subsequently decrease in affected animals, where clinical remission had been achieved following successful treatment. In the current study, serum CLU levels in dogs with MLSA were compared to healthy control dogs using both western blot and enzyme linked immunosorbent assay (ELISA). The presence of CLU in dog sera was confirmed by western blot analysis, detected at the predicted molecular weight, and the relative levels detected via western blot correlated with those detected by ELISA. Serum CLU analysis by ELISA found treatment naïve dogs with MLSA had a significantly (p&lt;0.001) lower serum CLU level in comparison to healthy controls. There was no significant difference in serum CLU concentrations between MLSA dogs prior to treatment and those in complete remission (CR). Serum CLU concentrations showed wide variation across all canine samples, limiting the potential as a single candidate biomarker for MLSA. The potential for any prognostic predictive value of serum CLU concentrations has yet to be assessed