Essentials Of Human Disease 2nd Edition by Leonard Crowley

Exercise 2

How does the body defend itself against abnormal cells that arise spontaneously in the course of cell division? What is the consequence of failure of these defense mechanisms (see Figure 1)?
Figure 1
Factors leading to neoplastic transformation of cells counterbalanced by immunologic defense against neoplasm. Conversion of a normal cell into an abnormal one requires activation of oncogenes and inactivation of tumor suppressor genes, which renders the cell unresponsive to normal control mechanisms that regulate cell growth. Generally, multiple step-by-step mutations are required to transform a normal cell into a cancer cell.