OLIVE OILS AND HEALTH 168 14.1. Cancer Fundamentally, cancer is a problem of abnormal cell proliferation (division). Cell proliferation is an essential process for living beings, but when altered it can trigger diseases such as cancer. At fertilisation, a single cell is formed containing the genetic material of both parents. This cell divides many times to form the various tissues and organs of the body, in a process that, alongside cell growth, also involves cell differentiation (specialisation) so that cells acquire the specific functions of each organ (lungs, heart, kidneys, etc.), with their activity coordinated by the nervous and endocrine systems. In maturity, the cells of an organ usually stop proliferating. However, when cells age or are damaged, they die and are replaced by new cells thanks to the proliferation of healthy ones, allowing full repair of the lesion. Cell division also plays a role in tissue regeneration arising from physiological changes, such as those occurring in the female reproductive organs during the menstrual cycle, or in the formation of spermatozoa in males. Once normality is restored, proliferation ceases and the cell acquires the functional capacity of the tissue to which it belongs. Furthermore, cells can die through a genetically programmed process known as apoptosis. An adult human body is made up of trillions of cells. Cell proliferation and differentiation are essential for life. When cells proliferate abnormally, the process is called neoplasia, leading to the formation of an abnormal mass (tumour) arising from the tissue of origin. This abnormal proliferation occurs because, in certain cells, alterations take place in the structure and/ or function of the genes that control cell proliferation and differentiation. Neoplasms may be benign or malignant, with only the latter constituting cancer. Therefore, there are no benign cancers, all cancers are malignant. Benign tumours are characterised by expansive, slow, and well-circumscribed growth, with the cells remaining at their site of origin and not spreading throughout the body. Cancer appears initially in a specific organ, and a single type of cancer can manifest and evolve in different ways. Consequently, the term cancer is a generic designation for a group of around 100 related diseases involving loss of control over cell proliferation, resulting in disordered growth unrelated to the physiological needs of the affected organ. Cancerous cells can eventually invade neighbouring tissues and spread to distant sites through the blood or lymphatic system, forming new tumours known as metastases. Metastases are the leading cause of cancer-related death. Cancer is a health problem present in all societies and has been known since ancient times. However, it is only in the last one hundred years that, following the decline in mortality from infectious diseases and the general increase in life expectancy, it has emerged as one of the most important causes of death in developed countries. Each year, approximately twenty million people (19.3 million in 2020) worldwide are diag-
RkJQdWJsaXNoZXIy Njg1MjYx