Biology of cancer: Nursing

Cancer is a group of malignant conditions characterized by uncontrolled and unchecked cell division and growth. Now, cancer can involve any organ in the body, with the most common ones being breast cancer, prostate cancer, lung cancer, and colorectal cancer, in addition to melanoma, leukemia, and lymphoma.

Now, let’s quickly review the physiology of cell division and growth, which takes place as a cell cycle in multiple phases: G1, S, G2, and M. During the G1 phase, the cell grows and prepares for DNA replication. In the S phase, the cell doubles its DNA content through DNA replication. This is followed by the G2 phase, during which the cell produces proteins and cellular components to be used in the next phase, called the M phase. Here, the cell divides through mitosis to produce two identical daughter cells.

Now, there are two types of genes that control the cell cycle, called tumor suppressor genes and proto-oncogenes. Tumor suppressor genes suppress uncontrolled cell division by preventing cells from entering the S phase; whereas proto-oncogenes stimulate cell division by encoding proteins involved in regulating the cell cycle.

Now, the main cause of cancer is gene mutation, or changes to the DNA sequence. These changes can be inherited from a parent, called germline mutations, or acquired throughout the client’s life, called somatic mutations. In addition, there’re epigenetic mutations, where tumor suppressor genes can be methylated and thus silenced, while proto-oncogenes can be unmethylated to activate their expression.

Mutations may arise due to a variety of risk factors. Non-modifiable risk factors include advanced age, in addition to personal or family history of cancer. On the other hand, modifiable risk factors include smoking, alcohol, obesity, excessive sun exposure, and certain occupations, as well as exposure to carcinogens, which are typically grouped into chemical, radiation, and viral carcinogens.