RT Journal Article T1 Cyclin D1 immunohistochemical expression and somatic mutations in canine oral melanoma A1 Zamboni, Clarissa A1 Brocca, Ginevra A1 Ferraresso, Serena A1 Ferro, Silvia A1 Sammarco, Alessandro A1 Dal Corso, Chiara A1 Iussich, Selina A1 Andrés Gamazo, Paloma Jimena de A1 Martínez De Merlo, Elena A1 Cavicchioli, Laura A1 Zappulli, Valentina A1 Castagnaro, Massimo AB Canine oral melanoma (COM) is the most frequent tumour with oral localization in dogs. Copy number gains and amplifications of CCND1, a gene coding for Cyclin D1, are the most frequent chromosomal aberrations described in human non-UV induced melanomas. Twenty-eight cases of COM were retrieved from paraffin-blocks archives. A total of 4 μm thick sections were immunostained with an antibody against human Cyclin D1 and Ki-67. Cyclin D1 and Ki-67 expressions were scored through two counting methods. DNA was extracted from 20 μm thick sections of formalin-fixed paraffin-embedded blocks. Pathological and surrounding healthy tissue was extracted independently. Cyclin D1 immunolabelling was detected in 69% (18/26) while Ki-67 was present in 88.5% (23/26) of cases. Statistical analysis revealed correlation between two counting methods for Cyclin D1 (r = 0.54; P = .004) and Ki-67 (r = 0.56; P = .003). The correlation found between Ki-67 and Cyclin D1 indexes in 16/26 cases labelled by both antibodies (r = 0.7947; P = .0002) suggests a possible use of Cyclin D1 index as prognostic marker. Polymerase chain reaction analysis on CCND1 coding sequence revealed the presence of nine somatic mutations in seven samples producing synonymous, missense and stop codons. Since none of the single-nucleotide polymorphisms was found to be recurrent, it is suggested that overexpression of Cyclin D1 may be the consequence of alterations of CCND1 upstream regions or other genetic aberrations not detectable with the methodology used in this study. Future studies are needed to verify the potential use of Cyclin D1 index as prognostic indicator and to highlight the molecular events responsible for Cyclin D1 overexpression in COMs. PB Wiley SN 1476-5810 YR 2019 FD 2019 LK https://hdl.handle.net/20.500.14352/95537 UL https://hdl.handle.net/20.500.14352/95537 LA eng NO Zamboni C, Brocca G, Ferraresso S, Ferro S, Sammarco A, Dal Corso C, Iussich S, de Andres PJ, Martìnez de Merlo EM, Cavicchioli L, Zappulli V, Castagnaro M. Cyclin D1 immunohistochemical expression and somatic mutations in canine oral melanoma. Vet Comp Oncol. 2020 Jun;18(2):231-238. doi: 10.1111/vco.12539. Epub 2019 Oct 9. PMID: 31503380. DS Docta Complutense RD 17 abr 2025