Pathological Findings in Gastrointestinal Neoplasms and Polyps in 860 Cats and a Pilot Study on miRNA Analyses

Abstract

Background: Gastrointestinal masses in cats are of clinical relevance, but pathological studies with larger case numbers are lacking. Biomarkers such as miRNA have not yet been investigated in feline intestinal neoplasms. Methods: A retrospective analysis of pathology reports included 860 feline gastrointestinal masses. Immunohistochemistry was performed on 91 lymphomas, 10 sarcomas and 7 mast cell tumours (MCT). Analyses of miRNA-20b and miRNA-192 were performed on 11 lymphomas, 5 carcinomas and 5 control tissues by ddPCR. Results: The pathological diagnosis identified 679 lymphomas, 122 carcinomas, 28 sarcomas, 23 polyps, 7 MCT and 1 leiomyoma. Carcinomas and polyps were most commonly found in the large intestine, lymphomas were most commonly found in the stomach and small intestine and MCT only occurred in the small intestine. Besides the well-described small-cell, mitotic count <2 T-cell lymphomas and the large-cell B-cell lymphomas with a high mitotic count, several variants of lymphomas were identified. The values of miRNA-20b were found to be up-regulated in samples of all types of cancer, whereas miRNA-192 was only up-regulated in carcinomas and B-cell lymphomas. Conclusions: The histopathological and immunohistochemical (sub-)classification of feline intestinal masses confirmed the occurrence of different tumour types, with lymphoma being the most frequent neoplasm. Novel biomarkers such as miRNA-20b and miRNA-192 might have diagnostic potential in feline intestinal neoplasms and should be further investigated.

miRNA Profiles of Canine Intestinal Carcinomas, Lymphomas and Enteritis Analysed by Digital Droplet PCR from FFPE Material

“…We confirmed that ddPCR using TaqMan miRNA assays is a robust technique for quantifying miRNA in canine FFPE samples, as previously shown in human and feline samples [ 30 , 31 , 32 ]. However, the isolation and quantification of miRNAs from FFPE material instead of fresh tissue is debatable.…”

“…Second, we investigated the miRNA profile of normal tissue compared with the different inflammatory and neoplastic diseases. We expected the two probably oncogenic miRNAs (miR-18b and 20b) to be up-regulated, as it has been described in canine T-cell lymphomas [ 16 ] and single samples of feline carcinomas, as well as T- and B-cell lymphomas [ 32 ]. Surprisingly, we did not find any mis-regulation of miR-18b in the T-cell lymphomas of the small intestine, or even down-regulation of miR-20b in the T-cell lymphomas and cases of lymphoplasmacytic enteritis of the small intestine.…”

“…In dogs, too, miR-192 seems to play a role in the progression of diseases related to the large intestine [ 19 ]. In contrast, in cats, miR-192 was found up-regulated in carcinoma and some B-cell lymphoma samples of the small intestine [ 32 ]. Since there have also been studies in humans describing miR-192 as being up-regulated [ 45 , 46 ] or down-regulated [ 46 ], the role of miR-192 in different types of tumours appears contentious.…”