The expression of serum lactate dehydrogenase in canine oral tumors

Abstract

Lactate dehydrogenase (LDH) has been reported to be a prognostic indicator of human malignant melanoma (MM),
lymphoma, renal cell carcinoma and prostate cancer. In veterinary medicine, elevation of serum LDH has been reported
in canine lymphoma and mammary gland tumors. However, the expression of the LDH in oral tumor-bearing dogs
has not been elucidated. In this study, serum LDH levels were evaluated and compared between healthy dogs (control;
n = 20) and oral tumor-bearing dogs (n = 34). Half of the tumor-bearing dogs (17dogs) had oral MM, followed by 6
dogs with oral squamous cell carcinoma (SCC), 4 dogs with fibrosarcoma (FS), 3 dogs with benign epithelial tumors
(BET), and 1 dog each with osteosarcoma, lymphoma, histiocytoma and acanthomatous ameloblastoma. Serum LDH
was significantly higher in oral tumor-bearing dogs (P = 0.0006). Besides, serum LDH expression of MM, SCC and FS
was significantly higher than that of the control group (P = 0.0078, 0.0030 and 0.0022, respectively). The expression of
serum LDH did not significantly correlate with the location of the primary tumor or the clinical stage of the disease,
the clinical stage II revealed the highest expression of the LDH though. The results indicate that serum LDH might be
useful as an indicator for oral tumors but further study examining a larger number of patients with each tumor type
would be advantageous.