Introduction:
The etiology of cryptorchidism is still not fully elucidated, but several hypotheses have been proposed. One of the latest concerns is the involvement of metalloproteinase ADAMTS16 in testis descent. The aim of this study was to evaluate both expression and occurrence of selected polymorphisms of metalloproteinase ADAMTS16 in patients diagnosed with cryptorchidism.

Material and methods:
The study group consisted of 158 boys (mean age: 4.1 ±2.04 years) who underwent surgery due to undescended testis. Tissue samples from patients with cryptorchidism were obtained from the cremaster muscle, gubernaculum and hernial sac. The reference group consisted of 123 age-related subjects (mean age: 4.1 ±2.41 years) who had no cryptorchidism and underwent surgery for other reasons. Tissue samples from controls were obtained from the cremaster muscle and hernial sac.

Results:
The obtained data indicate that patients with undescended testis have significantly lower expression of Adamts16, especially in the gubernaculum. We also demonstrated a tendency that Adamts16 expression depends on the age of patients; the older the patient was, the higher was the observed expression of Adamts16. These studies also established that polymorphisms rs16875319, rs16875122, and rs58353460 in the Adamts16 gene are not a major determinant to develop cryptorchidism while rs16875054 is associated with increased risk.

Conclusions:
These studies highlight ADAMTS16 involvement in cryptorchidism and confirm data obtained in animal models.