Expression of Platelet Derived Growth Factor a, Its Receptor, and Integrin Subunit Alpha V in Feline Injection-Site Sarcomas

Ishtiaq Ahmed,Sozmen Mahmut

doi:10.2478/acve-2021-0002

Abstract

Abstract Injection-site sarcomas are considered an important entity in veterinary oncology, especially in cats. The current study investigated the immunohistochemical expression of platelet-derived growth factor A (PDGFA), platelet-derived growth factor receptor-α (PDGFR-α), and integrin alpha subunit v in feline injection-site sarcomas (FISS). A total of 14 paraffin-embedded tissue samples previously diagnosed as soft tissue sarcomas were selected from the departmental archive and sectioned at 5µm using a microtome. Tissue sections were stained with Hematoxylin & Eosin, Alcian blue-Periodic Acid Schiff (AB-PAS), Masson’s Trichrome, and immunohistochemically for PDGFA, PDGR-α, and integrin alpha v. The majority of the tumors were fibrosarcomas (n=13/14), except one case of myxoid liposarcoma. The tumors occurred at sites commonly used for injections or vaccine administration. Histologically, tumors were characterized by peripheral infiltration of mononuclear cells mainly lymphocytes, variable sized central necrotic areas, and many multinucleated tumor giant cells. AB-PAS staining revealed the presence of myxoid or mucinous areas in (8/14) tumors while trichrome staining demonstrated a variable amount of collagenous stroma in 12/14 tumors. Vimentin immunoreactivity was observed in all the tumors while smooth muscle actin and muscle actin staining was noticed in four and two cases, respectively. PDGFA and PDGFR-α immunoexpression was observed in all 14 cases while integrin alpha v in 13/14 cases. The results of the current study indicate that fibrosarcoma is the major morphologic phenotype of FISS. The PDGFA, its receptor, and integrin alpha v immunoexpression are increased in these tumors in cats which elucidates their role in the pathogenesis of FISS.

Highlights

Injection-site sarcomas previously known as vaccine-associated sarcomas were first described in 1991 by Hendrick and Goldschmidt and the development of the tumorActa Veterinaria-Beograd 2021, 71 (1), 13-31 was initially attributed to the administration of vaccines having aluminum-based adjuvants [1]
Injection-site sarcomas are believed to originate in response to the injection of foreign materials in any animal species especially cats
13 cases of fibrosarcomas and one myxosarcoma were observed at the anatomical sites used for injections or vaccine administration in cats

Summary

Introduction

Injection-site sarcomas previously known as vaccine-associated sarcomas were first described in 1991 by Hendrick and Goldschmidt and the development of the tumorActa Veterinaria-Beograd 2021, 71 (1), 13-31 was initially attributed to the administration of vaccines (especially rabies) having aluminum-based adjuvants [1]. The risk for tumor development increases with the number of injections at the same site [7]. Various drugs especially long-acting penicillin and methylprednisolone acetate [8], lufenuron an insecticide used for flea control in animals [9], suture material [10], and microchip implants [11] have been mentioned as risk factors for sarcoma development in cats. Injection site sarcomas in the younger cats are more aggressive and are usually located in the subcutis and have peripheral infiltration of lymphocytes. Most of these have the myofibroblastic immunophenotype. Expression of matrix metalloproteinases including membrane-type matrix metalloproteinases in the FISS indicates the role of inflammation in the pathogenies of these tumors [15]

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