Upregulation of the PI3K/Akt Pathway in the Tumorigenesis of Canine Thyroid Carcinoma |
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| Authors: | M Campos MMJ Kool S Daminet R Ducatelle G Rutteman HS Kooistra S Galac JA Mol |
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| Institution: | 1.Department of Medicine and Clinical Biology of Small Animals, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium;2.Department of Pathology, Bacteriology and Poultry Diseases, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium;3.Department of Clinical Sciences of Companion Animals, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands |
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| Abstract: | BackgroundInformation on the genetic events leading to thyroid cancer in dogs is lacking.Hypothesis/ObjectivesUpregulation of the PI3K/Akt pathway has an important role in the tumorigenesis of thyroid carcinoma in dogs.AnimalsFifty‐nine dogs with thyroid carcinoma and 10 healthy controls.MethodsQuantitative RT‐PCR was performed for VEGFR‐1, VEGFR‐2, EGFR, PIK3CA, PIK3CB, PDPK1, PTEN, AKT1, AKT2, COX‐2, and CALCA. Mutation analysis was performed for known hotspots of RAS (N, K, H), PIK3CA, BRAF, RET, and for the entire coding region of PTEN.ResultsForty‐three dogs (73%) had follicular cell thyroid carcinoma (FTC) and 16 dogs (27%) had medullary thyroid carcinoma (MTC). The relative mRNA expressions of VEGFR‐1 (P < .001), VEGFR‐2 (P = .002), PDPK1 (P < .001), AKT1 (P = .009), and AKT2 (P < .001) were increased in FTC, and those of EGFR (P < .001), VEGFR‐1 (P = .036), and PIK3CA (P = .019) were increased in MTC when compared to normal thyroid glands. Mutation analysis of K‐RAS identified 2 activating missense mutations, which also have been described in thyroid cancer of humans. A G12R substitution was present in 1 FTC and an E63K substitution was present in 1 MTC. No functional mutations were found in the sequenced regions of H‐RAS, N‐RAS, PIK3CA, BRAF, RET, and PTEN.Conclusions and Clinical ImportanceThe increased expression of several genes associated with PI3K/Akt signaling suggests the involvement of this pathway in the pathogenesis of thyroid carcinoma in dogs, warranting further research on pathway activation and gene amplification. The mutations most frequently associated with thyroid cancer in humans are rare in dogs. |
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| Keywords: | C‐ cell Dog Follicular Medullary RAS |
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