Use of immunohistochemistry and polymerase chain reaction for detection of oncornaviruses in formalin-fixed, paraffin-embedded fibrosarcomas from cats.

OBJECTIVE

To determine whether there was intralesional infection or expression of FeLV or feline sarcoma virus in suspected vaccine-associated fibrosarcomas in cats.

DESIGN

Prospective case series.

SAMPLE POPULATION

130 suspected vaccine-associated fibrosarcomas from cats and 1 multicentric fibrosarcoma from 1 cat.

PROCEDURE

Excisional biopsy specimens were fixed in formalin and embedded in paraffin. Expression of FeLV antigen was assessed, using a polyclonal goat anti-FeLV glycoprotein 70 (gp 70) serum and an avidinbiotin immunoperoxidase staining technique. The FeLV genome was detected with a polymerase chain reaction (PCR), using primers targeted to a conserved sequence in the untranslated region of the long terminal repeat (LTR) of the FeLV.

RESULTS

FeLV gp 70 and LTR sequence were detected in a multicentric fibrosarcoma. All 130 of the suspected vaccine-associated fibrosarcomas were FeLV gp 70 negative on the basis of immunohistochemical test results: 100 fibrosarcomas also were examined by use of PCR and were negative for FeLV LTR region.

CLINICAL IMPLICATIONS

Exogenous retroviruses, FeLV, and feline sarcoma virus were not detected in these suspected vaccine-associated fibrosarcomas, using immunohistochemistry and PCR. Additional testing will be required to determine the nature of genomic alterations that are involved in the oncogenesis of vaccine-associated fibrosarcomas in cats.