Background

Primary testicular tumors occur commonly in aged dogs. The principal tumors of canine testes are seminoma, Sertoli cell tumor, and Leydig cell tumor, occurring with almost equal frequency. Although testicular tumors are common in dogs, there are not enough studies on tumor markers in these.

Aims

In this study, we seek to determine that the combined tumor markers for human testicular tumors, placental alkaline phosphatase (PLAP), OCT-4, CD30, alpha-fetoprotein (AFP), inhibin, vimentin are also useful to detect the canine testicular tumors.

Methods

A total of 13 canine testicular tumors were obtained from surgical specimens. The 12 canine testicular tumors comprised 7 seminomas, 4 Sertoli cell tumors, and 1 Leydig cell tumors. HE staining and immunohistochemistry was performed. Primary antibodies of PLAP, OCT-4, CD30, AFP, inhibin, and vimentin were applied. The antibodies are commonly used to differentiate germ cell tumors from sex-cord stromal tumors in human.

Results

AFP expression was observed in 1/7 (14.3%) seminomas, 4/4 (100%) Sertoli cell tumors, and 1/1 (100%) Leydig cell tumors. Inhibin was found in 1/7 (14.3%) seminomas, 4/4 (100%) Sertoli cell tumors, and 0/1 (0%) Leydig cell tumors. Vimentin was expressed in 2/7 (28.6%) seminomas, 4/4 (100%) Sertoli cell tumors, and 0/1 (0%) Leydig cell tumors. Unfortunately, PLAP, Oct-4, and CD30 were not expressed.

Discussion

In this study, AFP, inhibin and vimentin are tumor markers having specificity and sensitivity for canine testicular tumors. These markers can function as ones for differential diagnoses of canine testicular tumors.