Predictive value of RNAscope hybridization and p53 immunohistochemistry for mutational status in canine diffuse large B-cell lymphoma.

mutations are associated with short survival and poor treatment response in canine diffuse large B-cell lymphoma (cDLBCL). The expression of by RNAscope hybridization and p53 by immunohistochemistry (IHC) was investigated in 37 formalin-fixed paraffin-embedded cDLBCL, to assess their correlation with mutational status and to evaluate their prognostic value. was detected in all samples by RNAscope. Ten of 37 (27%) cases expressed p53 by IHC, with highly variable percentage of positive cells. RNAscope scores and p53 IHC results were not correlated. The expression of by RNAscope was not influenced by its mutational status. Conversely, p53 IHC and mutations were significantly associated. p53 IHC predicted genetic mutations with high accuracy (97.3%). All mutated samples carrying missense mutations exhibited p53 expression by IHC, while all wild-type cases and a single case with frameshift insertion were negative. In univariable analysis, p53 IHC was associated with shorter time to progression (TTP) and lymphoma-specific survival (LSS). Nevertheless, in multivariable analysis, only treatment significantly affected TTP and LSS. These findings suggest p53 IHC is an accurate, cost-effective tool for predicting mutations in cDLBCL, unlike RNAscope, though its prognostic value requires further validation.