CURRENT CONCEPTS OF CANCER.

Because the cancerous change in cells appears to be a permanent alteration, handed on to daughter cells through innumerable divisions, it seems probable that it reflects an abnormality in the transfer of information from cell to daughter cells. Transfer of information in cells is believed to depend on their genetic apparatus, and transfer of abnormal information implies that the genetic apparatus is not functioning normally. Abnormalities in genetic material, whether induced by ionizing radiation, chemical compounds or viruses, would, if reproduced at cell division, reappear in daughter cells. If such abnormalities lead to cancerous change in cells, any one of these primary incitants might be effective. Under such circumstances, the nature of the primary incitant may not be the most important question, and definition of the nature of the abnormality in the genetic material may become the central problem. It may ultimately be feasible to explain the cancerous change in cells in chemical terms and to find that it represents a molecular disease which takes its origin from the emergence of abnormal nucleotide sequences in the genetic material. In biological terms this would correspond with an induced mutation which is heritable at the level of the somatic cell.