DNA damage is a feature of feline injection-site sarcoma.

Abstract

Feline injection-site sarcoma (FISS) is commonly treated with surgery and radiation therapy. Despite aggressive therapy, FISS has a high recurrence rate. The true benefit of adjuvant chemotherapy is not known. DNA damage response mechanisms help protect against genomic instability but can also promote chemoresistance. In order to determine whether DNA damage is a feature of FISS, we evaluated tumour tissues with &#x3b3;H2AX immunohistochemistry. H2AX is phosphorylated to form &#x3b3;H2AX following DNA double strand breaks. Seventeen FISS specimens were evaluated prospectively. DNA damage ranged from 2.18 to33.7%, with a median of 16.2%. Significant differences were noted between cats (P&#x2009;<&#x2009;0.0001). Mitotic index ranged from 0 to 57 with a median of 13 and did not correlate with &#x3b3;H2AX positivity (P&#x2009;=&#x2009;0.2). Further studies are needed to determine if &#x3b3;H2AX expression may predict chemosensitivity and have independent value as a prognostic factor.