Progranulin (PGRN) is a pluripotent growth factor that has shown promise as a diagnostic and prognostic biomarker for various neoplastic conditions in humans. This study aims to explore the PGRN as a novel biomarker for diagnosing and predicting the prognosis in canine tumors. Dogs ( = 104) with tumors as the chief complaint were selected and classified based on clinical categorization, malignancy, and metastasis. The control group ( = 30) consisted of healthy dogs with no evidence of neoplastic diseases. Serum PGRN levels were quantified using enzyme-linked immunosorbent assay (ELISA). Dogs with tumors exhibited significantly elevated PGRN levels compared to control dogs ( < 0.0001), with a high sensitivity of 90.91%. Malignant tumors demonstrated markedly higher PGRN levels relative to the control group ( = 0.0012), while no significant difference was found between benign tumors and the control group. Additionally, serum PGRN was identified as a significant marker for differentiating metastatic tumors from non-metastatic ones ( = 0.0264). PGRN exhibited high sensitivity for tumor detection, suggesting that it may serve as a screening biomarker. Prognostically, increased PGRN correlated with unfavorable outcomes, notably linked to malignancy and metastasis. This study underscores the potential of PGRN as a novel biomarker with early diagnostic and prognostic value in canine oncology.