The incidence of seminoma and expression of cell adhesion molecule CD44 in cryptorchid boys and infertile men.

PURPOSE

The incidence of seminoma in men with cryptorchid testes is a contentious issue among physicians. Nevertheless, a positive correlation has been shown between the susceptibility for seminoma in patients with the oligo-asthenoteratospermia syndrome and in those with cryptorchid testes.

MATERIALS AND METHODS

We histologically examined 5,231 biopsies from 3,867 patients, including 1,121 men with the oligo-asthenoteratospermia syndrome, 218 men with azoospermia and 2,528 boys with cryptorchidism. Testicular tissue embedded in Epon was analyzed by light microscopy, fluorometry, electron microscopy and immunohistochemistry. Cell adhesion molecule CD44 was detected using a monoclonal antibody in all biopsies of patients suspected of having carcinoma in situ.

RESULTS

The incidence of seminoma was identical in boys with cryptorchidism and infertile men with the oligo-asthenoteratospermia syndrome but it was significantly higher than in the normal population. All biopsies were analyzed by a single investigator, including 2,528 from 2,403 cryptorchid boys and 2,322 from 1,339 infertile men. Seminoma was found in 4 cryptorchid boys of whom 3 had intra-abdominal testes. The incidence of seminoma in infertile men with the oligo-asthenoteratospermia syndrome was 6/1,121 (4 stage I and 2 stage II). Overall 10 seminomas were noted in 3,867 patients, including 1 in whom seminomas subsequently developed in both testes. Before the onset of puberty primordial germ cells persisted in 7 of the 2,528 cryptorchid patients, although no invasive seminomas were detected. An anti-CD44 monoclonal antibody was found to bind selectively to seminoma cells in the earliest stages of malignant transformation and metastasis, which to our knowledge represents the first reported incidence of CD44 expression associated with seminoma cells.

CONCLUSIONS

The incidence of carcinoma in situ in patients with the oligo-asthenoteratospermia syndrome or cryptorchidism was 0.27%. If the occurrence of primordial germ cells is considered, the overall incidence was 0.46% (17 of 3,659 cases). CD44 was expressed in all seminoma cells as well as in all primordial germ cells. Because CD44 adhesion molecules are expressed in the earliest stages of seminoma development, anti-CD44 monoclonal antibody is an important new tool for positively identifying this type of neoplasm in all cases.