Targeted variant analysis of feline mediastinal lymphoma using MassARRAY and clinical associations

Lymphoma is the most commonly diagnosed cancer in cats. This study used the Agena MassARRAY to genotype 40 variants across 17 genes in feline mediastinal lymphoma. These variants have previously been identified in tumors, including T- and B-cell lymphomas, acute and chronic lymphocytic leukemias, and mast cell tumors, in humans, dogs, and cats, using various methods. They were selected based on high prevalence reported in prior oncology studies, potential relevance to targeted therapy, and suitability for multiplex PCR amplification. Pleural fluid samples were collected from 76 cats with mediastinal lymphoma, including 69 domestic shorthairs, two Persians, two Siamese, two Wichienmaat, and one Scottish Fold. The most prevalent variants were found in the BCL2, KIT, STAT3, and ZEB1 genes. Specifically, BCL2 c.83275986G > A and c.83275992G > T were present in 71.1% and 57.9%, respectively. In cats with variant-positive in KIT c.163965724C > CT significantly reduced (11 days) compared to wild-type cats (94 days) (p < 0.001). In cats with variant-positive in STAT3 c.42942437C > CA, resulted in shorter median survival compared to wild-type cats (18 days vs. 77 days, p = 0.006). The findings suggest that the variant panel could be useful for the genomic landscape of feline mediastinal lymphoma and warrant further validation.