CHARACTERISTICS OF MALIGNANT CELLS
Despite their individual differences, all cancer cells share some common cellular characteristics in relation to the cell membrane, special proteins, the nuclei, chromosomal abnormalities, and the rate of mitosis and growth. The cell membranes are altered in cancer cells, which affects fluid movement in and out of the cell. The cell membrane of malignant cells also contains proteins called tumor-specific antigens (for example, carcinoembryonic antigen and prostate-specific antigen), which develop as they be-come less differentiated (mature) over time. These proteins dis-tinguish the malignant cell from a benign cell of the same tissue type. They may be useful in measuring the extent of disease in a person and in tracking the course of illness during treatment or relapse. Malignant cellular membranes also contain less fibro-nectin, a cellular cement. They are therefore less cohesive and do not adhere to adjacent cells readily.
Typically, nuclei of cancer cells are large and irregularly shaped (pleomorphism). Nucleoli, structures within the nucleus that house ribonucleic acid (RNA), are larger and more numerous in malignant cells, perhaps because of increased RNA synthesis. Chromosomal abnormalities (translocations, deletions, additions) and fragility of chromosomes are commonly found when cancer cells are analyzed.
Mitosis (cell division) occurs more frequently in malignant cells than in normal cells. As the cells grow and divide, more glu-cose and oxygen are needed. If glucose and oxygen are unavail-able, malignant cells use anaerobic metabolic channels to produce energy, which makes the cells less dependent on the availability of a constant oxygen supply.