Skip to 0 minutes and 15 secondsBefore we can treat disease, we need to know what we're dealing with. So working out the correct disease name or diagnosis is important. In this video, we'll learn about how tumours develop and behave. Then, we'll talk about how we name or classify tumours into benign and malignant, and by tissue type and site. Such tumour classification has, for over a century, formed the main basis of predicting how cancers will behave and how best to treat patients. As you will learn in the next weeks, knowledge about the underlying molecular and genomic changes is driving a revolution in cancer classification, predicting patient outcome, and in treatment. First, we will revise some important concepts presented earlier this week.
Skip to 1 minute and 7 secondsYou have already learned about cells and that similar cells are organised into tissues, then into organs, and then into integrated systems. Cells are controlled by DNA in the nucleus, which transmits its message via RNA to the cytoplasm. There, much of the RNA acts as a template to make the proteins which enable the cell to do its particular job. This is known as the cell's function or differentiation. Most normal body cells have the same DNA, with the exception of germ cells and some blood cells but their RNA and protein are different and specific to each cell type. What does that mean for us in terms of disease diagnosis and pathology?
Skip to 1 minute and 57 secondsNormal tissues do different things and look different from each other and different cells look different down the microscope. That means we can tell them apart. This is what pathologists do every day. The categories we use to classify normal tissues are similar to how we classify tumours. So we need to understand how normal tissues are classified. There are four broad tissue types, each composed of specific cells. The first tissue category is epithelium, which covers surfaces, lines tubes and hollow organs, and forms solid organs. Covering epithelia are usually squamous like skin. Lining epithelia are made of glands and line our gut, our lungs, and the male and female reproductive systems. Our liver and kidneys are made up of solid epithelia.
Skip to 2 minutes and 57 secondsThe second category is connective tissue, which supports us. This includes bone, cartilage, fat, blood vessels, and fibrous tissue. The third category includes blood, lymph nodes, and bone marrow. And the fourth category is nervous tissue, which includes the brain and nerves. Other cell types include melanocytes, which are brown and form moles on the skin; and germ cells in the ovary and testes. Now you know about normal cells and their functions. In real life, cells have to maintain their structure and do their job in an ever changing environment. Normal cells are aiming for a steady state, or homeostasis and have mechanisms to achieve this as described in the hallmarks of cancer. Usually, normal cells sense and easily adjust to mild changes.
Skip to 3 minutes and 54 secondsChanges can include a bigger or smaller functional demand on the tissue. Environmental changes or stresses can be external or internal. External factors include physical factors like radiation from the sun or too much heat or cold, chemicals, including food and infections. Internal factors include hormones and the immune response. More or less functional demand often causes a reversible abnormality of cell growth. Thus, we may get more cells or bigger cells, called hyperplasia or hypertrophy, or fewer cells or smaller cells, known as atrophy. A change in functional demand may cause cells to change from one type into another. This is called metaplasia. Metaplasia is common in the epithelium lining the airways in smokers.
Skip to 4 minutes and 53 secondsMetaplastic cells are more likely to keep changing and eventually may develop into lung cancer. These reversible changes can also be caused by environmental stresses. These can also cause disease under certain circumstances-- for example, if the environmental change is more intense or longer lasting, or if the cell is more sensitive than usual. Some stresses cause more severe cell injury and structural damage, with cell swelling and uncontrolled cell death, known as necrosis. This damage may, in turn, provoke a reaction from the body called inflammation. Inflammation is discussed again later in the course. Finally, and usually caused by injury over many years, cells may develop neoplasia. Cancer is one form of neoplasia.
Cancer pathology: what's in a name? Part one
Dr Karin Oien introduces the role of pathology in cancer. This is part one of a two-part video.
© University of Glasgow