Hormone receptor discrepancy and molecular subtype changes in canine mammary carcinomas and synchronous lymph node metastasis.

Mammary tumors are the most prevalent neoplasms in intact female dogs; up to 50 % are considered malignant and have the potential to metastasize to regional lymph node and distant organs. Changes in tumor molecular subtype, including its receptor status, can occur during mammary tumor progression. This study aimed to explore hormone receptor discrepancies and the relationship between molecular subtypes in primary mammary tumors (PTs) and paired lymph node metastases (LNMs).