Chronic inflammation in the tumor microenvironment has a prominent role in carcinogenesis and benefits the proliferation and survival of malignant cells, promoting angiogenesis and metastasis. Mammary tumors are frequently infiltrated by a heterogeneous population of immune cells where T-lymphocytes have a great importance. Interestingly, similar inflammatory cell infiltrates, cytokine and chemokine expression in humans and canine mammary tumors were recently described. However, in both species, despite all the scientific evidences that appoint for a significant role of T-lymphocytes, a definitive conclusion concerning the effectiveness of T-cell dependent immune mechanisms has not been achieved yet. In the present review, we describe similarities between human breast cancer and canine mammary tumors regarding tumor T-lymphocyte infiltration, such as relationship of TILs and mammary tumors malignancy, association of ratio CD4+/ CD8+ T-cells with low survival rates, promotion of tumor progression by Th2 cells actions, and association of great amounts of Treg cells with poor prognostic factors. This apparent parallelism together with the fact that dogs develop spontaneous tumors in the context of a natural immune system highlight the dog as a possible useful biological model for studies in human breast cancer immunology.

Background: Septicemia in human neonates frequently is complicated by activation of the coagulation system, disseminated intravascular coagulation (DIC) and multiple organ failure syndrome, which may contribute to high mortality. In adult horses with DIC, the lung has been the organ most frequently affected by fibrin deposits. In addition, in vivo studies suggest that hemostatic mechanisms may be immature in foals <1-day old. Hypothesis: Newborn foals with severe septicemia have fibrin deposits in their tissues independently of their age, and these fibrin deposits are associated with organ failure. Animals: Thirty-two septic and 4 nonseptic newborn foals euthanized for poor prognosis. Methods: Tissue samples (kidney, lung, and liver) collected on postmortem examination were stained with phosphotungstic acid hematoxylin (PTAH) and immunohistochemistry (IHC) for blind histologic examination. A fibrin score (grades 0–4) was established for each tissue sample and for each foal. Medical records were reviewed for assessing clinical evidence of organ failure during hospitalization. Results: Fibrin deposits were found in most septic foals (28/32 when using IHC and 21/32 when using PTAH), independently of the age of the foal. The lung was the most affected tissue (97% of the septic foals). Additionally, organ failure was diagnosed in 18/32 septic foals (8 with respiratory failure, 14 with renal failure), although a statistical association with severe fibrin deposition was not identified. Conclusions and Clinical Importance: Nonsurviving septic foals have fibrin deposits in their tissues, a finding consistent with capillary microthrombosis and DIC.