Trabajo Fin de Grado defendido por Adrian Arribas Mercado

11 de julio de 2025

Gastric carcinoma represents 60–70% of gastric neoplasms in dogs. The malignancy of these neoplasms is based on cellular characteristics such as pleomorphism, anisocytosis, anisokaryosis, atypical mitoses and mitotic index among others; but undoubtedly, migration, infiltration and metastasis of neoplastic cells are the criteria that determine the invasiveness of a tumor. These criteria can be determined by immunohistochemical study of certain transmembrane proteins called integrins. These molecules are composed of two separate subunits, ? (alpha) and ? (beta) subunits, which combine to form different heterodimers that promote cell attachment to the surrounding extracellular matrix. In human and veterinary medicine, aberrant expression of some of these integrins has been correlated to the different
stages of metastasis in several types of cancer, including gastric tumors. In this study, stomach biopsies from 25 dogs from the VetPatólogos laboratory processed at the Pathology and Forensic Veterinary Service of the VISAVET center were included. Histopathologically, they were classified according to WHO criteria for domestic animals and malignancy characteristics were analyzed. The most common type was signet ring cell carcinoma (SRCC) (52%, n=13), followed by undifferentiated (28%, n=7) and tubular (24%, n=6). Immunohistochemical study revealed immunoexpression of ?1, ?3, and ?1 integrin subunits in tumor cells, using the following score: 0 (absence), 1 (mild), 2 (moderate), and 3 (intense). For all three subunits, superficial tumor cells located in the primary tumor presented on average a lower intensity of
immunoreactivity than the lining epithelium and non-neoplastic glands. Likewise, an increase in immunoexpression was observed in the most infiltrative and metastatic cells, similar or higher to that described in the epithelium. Of all three tumor types, cCAS showed the lowest immunoexpression of the integrins studied, while it was higher in undifferentiated and tubular carcinomas. Mesenchymal cells on the interstitium showed a mild immunoreaction, although it increased in certain cells like the tumor-associated fibroblasts. These results provide important information about the involvement of ?1, ?3 and ?1 subunits in the morphology and biological
behavior of each type of gastric carcinoma in the dog, as well as in the phenomenon of
metastasis.
Keywords: Canine gastric carcinoma, histopathology, immunohistochemistry, integrins,
metastasis