Elevated oncogene expressions in koala infected with multiple koala retrovirus subtypes: a preliminary study.

Koala retrovirus (KoRV) causes multiple disease phenotypes in koalas, including carcinogenesis. The study aimed to assess oncogene expression in spleen tissues from ten deceased koalas coinfected with different subtypes and peripheral blood mononuclear cells (PBMCs) from two subclinically coinfected koalas with KoRV-A and KoRV-B. Initially, KoRV subtyping involved amplifying endogenous KoRV-A, and exogenous KoRV-B, -C specific env gene fragments, followed by sequencing. Using quantitative real-time polymerase chain reaction (RT-qPCR), we examined five oncogenes (BCL2, BAX, BCL2L1, BCL3, and MYC) in spleen and PBMCs from dead and alive koalas coinfected with multiple KoRV subtypes, respectively. Significant (p < 0.05) increases in BCL2 and BAX oncogene expression were observed in deceased koalas that were coinfected with multiple KoRV subtypes compared with healthy koalas. Thus, this study highlights a potential link between KoRV subtype infections, oncogene expression, and koala diseases.