TGF-ß1, EGF and FGF4 synergistically induce differentiation of the seminoma cell line TCam-2 into a cell type resembling mixed non-seminoma.

Malignant germ-cell tumours arise from a neoplastic precursor, the carcinoma in situ, and develop into seminomas and/or non-seminomas (embryonal carcinomas, teratomas, yolk-sac tumours and choriocarcinomas). Based on histological and clinical findings, it has been postulated that seminomas can eventually transform into non-seminomas. Here, we used the cell line TCam-2 as model for seminomas and interrogated their differentiation potential. We demonstrate that TCam-2 cells are able to differentiate into mixed non-seminomatous lineages after supplementing the media with TGF-ß1, EGF and FGF4. On a molecular level, the differentiation is initiated by repression of BMP/SMAD signalling. As a consequence, BLIMP1, a molecule known to inhibit the differentiation of murine primordial germ cells, is down-regulated and differentiation-inhibiting histone modifications are lost. The appearance of multinucleated giant cells and the expression of marker genes indicate that cells differentiate predominantly into extra-embryonic choriocarcinoma-like cells. This is most likely due to the presence of components of the Hippo pathway, TEAD4 and YAP1. These molecules have been described to trigger extra-embryonic fate determination in the murine system. This study supports the model that seminomas indeed have an intrinsic ability to transform into a non-seminoma. In addition, the data suggest that the transformation does not require an additional mutation, but can be triggered by changes in the tumour microenvironment.

Choriocarcinoma in infant and mother.

A 2-month-old female baby was noticed to have liver tumor. A hemangioma of the right lobe was suspected from the findings by celiac angiography. Histologic findings of the surgically resected material revealed choriocarcinoma of the liver. At autopsy, multiple metastatic nodules were found in the lungs, but remnant liver, ovaries, uterus, mediastinum, and sacrococcygeal region were free of tumor. The ovary had several thecalutein cysts, and the endometrium of the uterus showed pseudodecidual change of the stroma. The mother died two months later. Although histologic materials were not available, the clinical findings including a high value of serum HCG seemed to show that she had been affected by choriocarcinoma. The most probable origin of the choriocarcinoma in the infant from the mother is discussed.

Pathogenesis of teratoid tumors of the ovary and testis.

Based upon a representative sample of testicular tumors studied at the Armed Forces Institute of Pathology, several testicular and ovarian tumors observed in Denver, pertinent papers in the literature, and the singular thesis of Chevassu on tumors of the testis, the pathogenesis of such neoplasms is elaborated. The findings are philosophical, speculative, and established. Man is a multicellular individual to be regarded as a vehicle for the transmission of unicellular organisms or germ cells from one generation to the next. These cells remain distinct from somatic and trophoblastic cells. The mature human female not only tolerates the normal expression of the fertilized ovum during pregnancy (sex cells, blastoderm, and trophoblast) but also seems capable of greater differentiation of immature somatic cells resulting from parthenogenesis of one or more ova into cells of the three germ layers, as well as the suppression of the growth of neoplastic sex cells and trophoblast cells, with benign cystic teratoma as the most common culmination. The preponderance of malignant teratoid tumors before sexual maturity is a corollary. In contrast, the human male is not equipped with organizers postulated for the human female and thus is unable to differentiate malignant immature somatic cells, the most common cancerous element in testicular tumors. The explanation for such neoplasms must be on the basis of segregation of such cells and abnormal spermatogonia or less often trophoblastic cells in the embryo, with later expression as neoplastic cells, since spermatogonia and progeny are unable to form a new individual. To paraphrase Wilms, the statement may be made that malignant testicular and ovarian tumors of teratoid type are related, despite their different microscopic appearance, to a common form. They differ only in the quality, not in the quantity, of the different tissues comprising them. These tumors contain neoplastic blastodermic cells and differentiated cells of the three germ layers, neoplastic sex cells, and neoplastic trophoblastic cells. The cells of these tumors and the tissues they form resemble very nearly the tissues of the human embryo with nonaxial formation of alimentary and respiratory structures in many instances. The notable frequency of variably differentiated neural elements in the teratoids tumors of the ovary is in sharp contrast to their uncommon occurrence in like tumors of the testis. Dysgenesis of the ovaries and the testes of testicular feminization syndrome should be regarded as likely soil for the development of teratoid tumors.