On the nature of oncogenic transformation of cells

The development of a malignant tumor is due to a desperate asexual self-cloning process in which cancer stem cells develop the ability to mimic the genetic program of germline cells

To date there is no explanation why the development of almost all types of solid tumors occurs sharing a similar scenario: (1) creation of a cancer stem cell (CSC), (2) CSC multiplication and formation of a multicellular tumor spheroid (TS), (3) vascularization of the TS and its transformation into a vascularized primary tumor, (4) metastatic spreading of CSCs, (5) formation of a metastatic TSs and its transformation into metastatic tumors, and (6) potentially endless repetition of this cycle of events. The above gaps in our knowledge are related to the biology of cancer and specifically to tumorigenesis, which covers the process from the creation of a CSC to the formation of a malignant tumor and the development of metastases. My Oncogerminative Theory of Tumorigenesis considers tumor formation as a dynamic self-organizing process that mimics a self-organizing process of early embryo development. In the initial step in that process, gene mutations combined with epigenetic dysregulation cause somatic cells to be reprogrammed into CSCs, which are immortal pseudo-germline cells. Mimicking the behavior of fertilized germline cells, the CSC achieves immortality by passing through the stages of its life-cycle and developing into a pseudo-blastula-stage embryo, which manifests in the body as a malignant tumor. In this view, the development of a malignant tumor from a CSC is a phenomenon of developmental biology, which we named a desperate asexual self-cloning event. The theory explains seven core characteristics of malignant tumors: (1) CSC immortality, (2) multistep development of a malignant tumor from a single CSC, (3) heterogeneity of malignant tumor cell populations, (4) metastatic spread of CSCs, (5) invasive growth, (6) malignant progression, and (7) selective immune tolerance toward cancer cells. The Oncogerminative Theory of Tumorigenesis suggests new avenues for discovery of revolutionary therapies to treat, prevent, and eradicate cancer.

Three steps mutation model of carcinogenesis

Based on recent data, this model supposes that benign and malignant tumors arise when a specific mutation takes place in a specific protein-kinase encoded by a proto-oncogene in a pluripotent stem cell or a committed stem cell. Protein-kinases which are regulated by tissue growth stimulating factors, tissue growth inhibiting factors and differentiating factors phosphorylate specific proteins that can derepress specific genes leading to cell division and cell differentiation. Malignant tumors arise when three mutations happen in a same pluripotent stem cell or committed stem cell: positive mutation at the level of tissue growth stimulating factor; negative mutation at the level of tissue growth inhibiting factor; negative mutation at the level of tissue differentiating factor. Higher expression of oncogenes and amplification reflect the relationship between tumor and host. Chromosomal rearrangements are secondary events that can be important because they may involve genes which are normally not involved in cell division and cell differentiation.

The pathology of head and neck tumors: papillomas of the upper aerodigestive tracts, Part 18

The human papillomavirus class of DNA viruses are more than circumstantially related to oral and airway papillomas. Whether they are fully oncogenic, in the malignant sense, without other agents is questionable. Recent advances in molecular virology and the use of genus-specific (common) antigen-antibody reactions have identified papillomavirus in laryngeal and oral papillomas. Laryngeal and oral papillomas could be precancerous lesions, but they show a low-risk and long-time interval leading to malignancy unless significant iatrogenic or host variables--such as radiotherapy or immuno-incompetence--are added. Two different papillomas in the larynx can be recognized; a nonkeratinizing, papillomavirus-related lesion, and a keratinizing, usually solitary papilloma, which may or may not be related to a virus genesis and may be equated with a keratosis or clinical leukoplakia.

A model for the study of the long duration pathogenesis of cancer and its relevance to therapy

The problem of comparing human cancer, a disease of long evolution, with experimental models in short life span animals is discussed. It is suggested that malignant tumors are more common in long life span animals because of the requirement of long periods of time for tumor progression. Increased malignancy may result from the ability of tumor cells to change, coupled with the long exposure of the neoplastic cells to the selective forces of the organism and the environment. It is proposed that the dynamic nature of tumors and the time required for changes to be expressed, should be taken into account in the study of the changing biological behavior of tumor cells and their changing responses to therapy. The use of transplantable tumors which increase in malignancy during successive transfers, artificially prolongs the existence of the neoplastic cells in isogeneic hosts, permitting thereby tumor progression. Tumor progression, occurs during a period which is accessible to the therapist. This dynamic process should be of primary interest to cancer researchers and therapists.