subject: The Meaning Of Cancer Gene [print this page] If the cancer gene is a confusing and imprecise meanings, the anti-cancer gene is ambiguity as well. The authors believe that the so-called oncogenes and anti-cancer genes are a large class of genes that control cell growth and differentiation. For their single gene, its product has the function of the different types of cell and can even the stage of cell developments. The relative meanings of oncogene and the anticancer gene are the exactly opposite effects of the same cancer gene and its product in different cells. The most typical example is the ras gene and its product of p21. There is sufficient evidence in the fibroblasts that the microinjection of the p21 protein can cause cells to S phase rapidly and began to split. The human ras gene can make some deterioration of fibroblasts and the epithelial cells. But for the professor pheochromocytoma pc12 cells, which is the point mutations, it stops dividing and begins to differentiate by introducing ras gene or microinjecting the p21 malignant cells. There is no doubt that the src gene can make a carcinogenic effect of the fiber cells of the chickens. But in the process of embryonic development, there is a closely relation of the differentiation of the nervous system of the src gene expression. It is estimated that this example may not be the only one. According to the biological significance, ras gene is the cancer gene for the fiber cell, but for the pc12 and it is the anticancer gene. The same gene product, whether it is the promotion of the growth or inhibition of the growth, whether it is an anticancer or carcinogenic, it does not seem to depend on the gene itself, but it depends on the differences of the cell category. Also it prompts different cells to the effects of the ras gene product system. Therefore, the final biological functions is different. The double meaning of the promotion and the inhibition of the growth substances. Suggesting the name, the growth factor should be included in the category of oncogenes and the growth inhibitory factor column should be classified as anti-cancer gene. In fact, there is great difference of the growth factor on the role of different cells. In addition to the factors receptors, not only the growth factors can promote cell growth, but also inhibit the cell growth can do it. Similarly, the growth inhibitory factor not only can inhibit cell growth, but also can promote cell growth. Therefore, it is clearly unreasonable that you determine which genes promoting or inhibiting the growth before distinguishing the types of cells.
