A suggested mechanism for changing tumor cell phenotype: transfection of host cells with DNA sequences of dead tumor cells.
In observing the phenomenon of alterations of tumor cell phenotypes, one may envision a mechanism that induces the change in tumor cell characteristics and the appearance of metastasis. Schirrmacher (1) has suggested that the effect of the microenvironment on tumor cells influences the control of gene expression and that together with a selective process it may result in a newly arising phenotype. I suggest that in certain tumors the phenotypic change is the result of transfection of a mitotically active cell with certain DNA sequences arising from the tumor cells. Indirect evidence of support this suggested mechanism may be found in experimental results either interpreted differently or that happened to be by-products of experiments designed for other purposes. The appearance of tumors that acquire the allogeneic markers of their new allogeneic hosts suggests in vivo transfection with transforming DNA sequences (2, 4, 5, 6 7, 8). Experimental transfection of cells with DNA sequences resulting in transformation (19) strengthens this hypothesis. According to this hypothesis the immune system has a dual role in tumor alteration, it carries out the selection and it also induces the transformation of future new tumor phenotypes due to its potential to increase the availability of DNA breaks in the microenvironment.
D000818:Animals; D001483:Base Sequence; D004273:DNA, Neoplasm / Q000235:genetics*; D006801:Humans; D007940:Leukemia L5178 / Q000235:genetics / Q000276:immunology; D051379:Mice; D009368:Neoplasm Transplantation; D009369:Neoplasms / Q000235:genetics* / Q000276:immunology; D010641:Phenotype; D014162:Transfection; D014185:Transplantation, Isogeneic
D004273:DNA, Neoplasm