Relationship between mast cell density and microvascular density with pathological features in canine mammary gland carcinomas

Canine mammary gland tumors (CMGTs) are among the most common neoplasms in female dogs, and serve as valuable models for human breast cancer in terms of histopathology and biological behavior. This study aimed to investigate the relationship between mast cell density (MCD) (total, peritumoral, and intratumoral) and microvascular density (MVD), and to determine their association with clinicopathological features in 40 canine mammary carcinomas (CMCs). The mast cells (MCs) assessment was conducted by utilizing standard Giemsa staining. To evaluate angiogenesis, the immunohistochemical expression of CD31 was assessed. Results revealed that peritumoral MCD was significantly higher than intratumoral MCD (P < 0.001). Higher histological grades (Grade III) exhibited increased MVD (P = 0.09) and total/intratumoral MCD (P = 0.031 and P = 0.020, respectively). Necrosis was associated with elevated MVD (P = 0.04) and intratumoral MCD (P = 0.027). However, no correlation was found between MVD and MCD, nor were significant differences observed among histological subtypes and lymphovascular invasion. These findings indicate that mast cells might play a role in tumor progression, potentially by promoting angiogenesis. Additionally, their distribution could serve as an extra histopathological marker that, when combined with traditional grading, may enhance prognostic accuracy for CMCs. Further studies with larger cohorts are needed to highlight the complex role of mast cells in the tumor microenvironment.