Twist is inversely associated with claudins in germ cell tumors of the testis

Abstract

We investigated the expression of claudins 1, 3-7 and transcriptional factor twist in a set of testicular germ cell tumors. The material consisted of 17 seminomas, 13 teratomas, 9 teratocarcinomas, 20 embryonal carcinomas and 9 mixed germ cell tumors. They were immunostained with antibodies to claudins 1, 3-7 and twist. As expected, all claudins were variably present in germ cell tumors with epithelial elements or differentiation, but the intensity of expression varied depending on the claudin type. Mesenchymal elements in teratomatous tumors remained negative for claudins. Expression of different claudins was less intense and inconsistent in other types of germ cell tumors. Choriocarcinomatous elements in germ cell tumors expressed relatively strongly claudin 4 and weaker positivity for claudins 5-7, while claudins 1 and 3 were negative. Seminomas showed expression only for claudins 5 and 7. The transcriptional factor twist was most strongly expressed in seminoma followed by embryonal carcinoma. Twist expression was inversely associated with several claudins (claudins 1, 3, 4 and 6). Germ cell tumors vary in their expression of claudins 1-7. Twist expression was inversely associated with several claudins, suggesting that it takes part in the downregulation of claudins in testicular tumors.

Claudins and germ cell tumors

“…Claudin expression in these tumors is analogous to the expression found in tissues of the comparable non-neoplastic tissues in human body (43). Thus expression of claudins 1, 2, 3, 4, 5 and 7 is usually amply found but expression is different in squamous or glandular epithelia (43). Squamous epithelium expresses strongly claudin 1 and 4 but claudin 3 is weakly or negatively expressed (43).…”

“…Of benign germ cell tumors a good example is teratoma which contains full developed components of epithelial, mesodermal and/or neural elements (54,58). Claudin expression in these tumors is analogous to the expression found in tissues of the comparable non-neoplastic tissues in human body (43). Thus expression of claudins 1, 2, 3, 4, 5 and 7 is usually amply found but expression is different in squamous or glandular epithelia (43).…”

“…Thus expression of claudins 1, 2, 3, 4, 5 and 7 is usually amply found but expression is different in squamous or glandular epithelia (43). Squamous epithelium expresses strongly claudin 1 and 4 but claudin 3 is weakly or negatively expressed (43). On the other hand, glandular epithelia express claudin 3 strongly in teratomas (43).…”

“…In human testicular tissues claudin 1, 6 and 7 protein expression has been found in seminiferous tubules (43). In rete testis epithelium, claudins 1 and 7 are strongly expressed while claudin 4 is weak and claudins 3, 5 and 6 are negative (43).…”

“…In rete testis epithelium, claudins 1 and 7 are strongly expressed while claudin 4 is weak and claudins 3, 5 and 6 are negative (43). Claudin 11 is present in Sertoli cells and takes part in formation of the blood testis barrier (44).…”