Suppression of antitumor lymphocyte mediated cytotoxicity by human chorionic gonadotropins

A proposed model of cancer as the inappropriate expression of non-body introns

An a posteriori proposal is made that cancer represents an alien non-body phenotype erupting from "silent" gene groups within actively coding regions of a normal cell's genome. Relevant empirical data is garnered from the literature and twelve premises are derived from the data. On the basis of these premises it is hypothesized that the malignant neoplastic phenotype results from interference with non-histone chromosomal proteins causing retention and expression in a body cell of non-body introns. These are asserted to be the same introns which, as exons in a trophoblast cell, direct the normal development of the fetal placenta. Development of a malignant tumor is presented as a pathological recapitulation of the development of a normal placenta. Unrestrained tumor growth is attributed to the inability of endogenous body chalones to suppress the non-body gene groups coding for neoplastic mitosis, while invasion and metastasis result from failure of the non-body genes which code for implantation and mitosis to switch off at the proper time. The hypothesis asserts that all carcinogenic agents alter phosphorylation of non-histone chromosomal proteins, that cancer and normal trophoblast cells are genetically programmed to travel through the body's vascular system to effect immunosuppression in lymphoid tissues, that malignant neoplastic tissue will regress when exposed to trophoblast-based chalones, and that mammals immunized against trophoblast-based antigen will be resistant to the development of malignant tumors.

Interaction of choriocarcinoma cells and human peripheral blood lymphocytes. Resistance of cultured choriocarcinoma cells to cell-mediated cytotoxicity by mitogen-activated lymphocytes

Cultured choriocarcinoma (Be Wo) cells exist that share many of the morphologic and bio-synthetic properties of normal human trophoblasts. In an attempt to develop a model for the immunologic relationship between a sensitized mother and fetus, we mixed Be Wo cells with mitogen-activated cytotoxic lymphocytes in vitro. Be Wo cells were resistant to the cytolytic effects of the activated lymphocytes despite 24-h exposure and intimate cell-to-cell contact as determined by microscopy. Control target cells, a line of human hepatoma cells, were readily destroyed. Cytotoxicity was measured by determining residual radioactivity of [(3)H]thymidine-labeled target cells after exposure to activated lymphocytes. Employing the quantitative assay, we confirmed the morphologic results and showed that Be Wo and a number of other choriocarcinoma cell lines were resistant to the cytotoxic effects of lymphocytes activated by phytohemagglutinin, pokeweed mitogen, and allogeneic cells in mixed lymphocyte cultures. Moreover, Be Wo cells were resistant to injury over a wide range of killer to target cell ratios. Significant killing of the Be Wo cells occurred only after prolonged exposure (48 and 72 h) to the activated lymphocytes. We suggest that one mechanism that may assist the fetus (or a choriocarcinoma) in its immunologic survival is the intrinsic resistance of trophoblast cells to lymphocyte-mediated cytotoxicity.

Alpha-fetoprotein and human chorionic gonadotropin in the management of testicular tumors

Alpha-fetoprotein and human chorionic gonadotropin levels were measured by radioimmunoassays in 260 patients with genitourinary diseases, including 93 patients with testicular tumors. Elevations of alpha-fetoprotein and human chorionic gonadotropin were associated only with non-seminomatous germ cell testicular tumors. Our 32-month experience with serial measurements of the 2 markers in patients with these tumors shows that alpha-fetoprotein and human chorionic gonadotropin must be determined and that together they serve as accurate and sensitive indicators of metastases and are helpful in determining the effectiveness of therapy. However, they have limited value in the differential diagnosis of scrotal masses.