Immunohistochemical expression and prognostic significance of MAGE-A in canine oral malignant melanoma. (July 2021)

• Record Type: Journal Article
• Authors: Guillén, Alexandra; Stiborova, Katerina; Ressel, Lorenzo; Blackwood, Laura; Finotello, Riccardo; Amores-Fuster, Isabel; Jama, Nimo; Killick, David
• Is Part Of: Research in veterinary science. Volume 137(2021)
• Page Start: 226
• Page End: 234
• Publication Date: 2021-07
• Subjects: Immunohistochemistry -- MAGE-A -- Melanoma -- Cancer testis antigens; COMM canine oral malignant melanoma -- MAGE melanoma-associated antigen -- TAA tumour associated antigen -- CT computed tomography -- WHO world health organization -- IHC immunohistochemistry -- TMA tissue microarray -- MST median survival time -- MI mitotic index -- HPF high power field; Veterinary medicine -- Periodicals; Veterinary Medicine -- Periodicals; Médecine vétérinaire -- Périodiques; Médecine vétérinaire -- Recherche -- Périodiques; Diergeneeskunde; 636.089
• DOI: 10.1016/j.rvsc.2021.05.009
• Languages: English
• ISSNs: 0034-5288

Abstract

Summary: Canine oral malignant melanoma (COMM) is considered a chemo-resistant cancer with a poor long-term prognosis. The melanoma-associated antigen A ( MAGE-A ) genes, which belong to the cancer-testis antigen family, are expressed in several different canine cancers but not in normal somatic tissue. This study evaluates the expression of MAGE-A proteins and their prognostic role in COMM. The study was conducted in 2 parts. During the first part, biopsies from oral malignant melanomas from 43 dogs were examined and immunohistochemically assessed for expression of MAGE-A proteins. For the second part, the association between MAGE-A expression and outcome was assessed using follow-up data which was available for 20 dogs whose primary tumour had been controlled with surgery +/− radiation therapy. MAGE-A proteins were expressed in 88.4% (38/43) of oral malignant melanomas and had a predominantly cytoplasmic expression pattern. Immunopositivity was observed in more than 50% of the cells in 21 dogs (48.8%). Immunostaining intensity was classified as weak, moderate and intense in 16 (37%), 16 (37%) and 6 (14%) cases, respectively. No staining for MAGE-A was seen in 5 dogs (11%). Dogs whose COMM had weak MAGE-A staining intensity had a median survival time (MST) of 320 days while this was 129 days for dogs with moderate and intense immunostaining ( p = 0.161). Dogs whose COMM had >50% of positive staining neoplastic cells had an MST of 141 days and dogs with a staining <50% had an MST of 320 days ( p = 0.164). MAGE-A expression did not influence survival in our cohort. Highlights: MAGE-A proteins were expressed in 38 of 43 of oral malignant melanomas with a predominant cytoplasmic pattern. In 21 of 43 of oral malignant melanomas, immunopositivity for MAGE-A was observed in more than 50% of the cells. The immunostaining had variable degrees of intensity, ranging from absent to intense. No correlation between MAGE-A immunopositivity or intensity and clinico-pathological parameters was found. MAGE-A expression did not influence survival in our cohort of dogs.