[MUSIC] Hello and welcome to the Johns Hopkins School of Medicine course on the Introduction to Cancer Biology. My name is Ken Pienta and I'm a professor or Urology, Oncology, and Pharmacology at the Johns Hopkins School of Medicine. And I've been a cancer researcher and physician for over 25 years. We put this course together because cancer is one of the most devastating diseases that strikes men, women, boys and girls in the US and as we will show you worldwide. It is a disease that is increasing, it is a disease that's increasing in incidents as well as every year it kills more and more people. We hate cancer, we want to find ways to find cancer and treat cancer. We are hoping that this introduction will give you a sense of the problem. Not only how it affects people and their families, but the biology of how it starts, and what many of the questions are in learning how to try to understand cancer better, and to treat cancer better. So we are offering this course as a way to attract you to the field. To understand cancer better, to contribute to understanding cancer better. To contributing to diagnosing it. To contributing to treating it. To hopefully finding a cure someday for this devastating disease. This first lecture is going to be on the Incidence and Etiology of Cancer. At the end of this module you will be able to define cancer, understand where cancer starts, identify the most common types of cancer and identify the risk factors for the common types of cancer. The lecture outline we're going to go through the cancer terms and definitions, the incidence in men and women, globally in the US of cancer overall, and then we're going to talk about the six most common cancers worldwide, lung cancer, colon cancer, breast cancer, prostate cancer, and stomach, and liver cancer. Let's start with cancer terms and definitions. What is cancer? In it's simplest form, it means uncontrolled growth. It's the disease caused by an uncontrolled division of abnormal cells in the part of the body. It's often also referred to as a tumor. Tumor is defined as a swelling of a part of the body, generally without inflammation, caused by an abnormal growth of tissue whether benign of malignant. Cancer is also sometimes referred to as a neoplasm. Which is defined as a new and abnormal growth of tissue in some part of the body. At its heart, cancer is a genetic disease. It is caused by an accumulation of detrimental variations in the genome over the course of a lifetime. These are a lot of terms that are new, and will be described in subsequent lectures. It's important to remember that most of the time a single mutation in your genes is not sufficient to induce cancer formation. Where does the word cancer come from? The origin of the word cancer is from the Greek karkinos, or crab. And it was termed this because the Greek physicians Hippocrates and Galen, among others, noted how a cancer looked like a crab as tumors had swollen veins along the skin. It then evolved to the Latin term cancer which also means crab or later, malignant tumor. Interestingly enough in the old English, cancer meant spreading sore or cancer. The study of cancer is oncology, and where does the word oncology come from? It literally means a branch of science that deals with tumors and cancers. The word onco means bulk or mass or tumor, while logy means study. So it's the study of a bulk or a tumor. An important word in cancer is metastasis. Metastasis is the spreading of cancer from a primary site to distant organs and it literally comes from the Greek word metastasis, which is removing, removal or migration, a changing, a change, or revolution. So again the metastasis, which means the spread of cancer from primary site, to distant organs is an important to learn early in the study of cancer. Where does cancer start? Cancers are classified according to the tissue where they originate. There are four main types. Carcinomas arise in epithelial tissue that is found in the internal and external linings of the body. Adenocarcinomas, which are the most common form of cancer develop in an organ or gland. For example, prostate cancer, breast cancer, liver cancer. Squamous cell carcinomas develop in the squamous epithelium of organs, including the skin, bladder, esophagus, and lung. Sarcomas, which account for less than 10% of all cancers, arise from connective tissue that is found in bones, tendons, cartilage, muscle, and fat. Leukemias are cancers of the blood that originate in the bone marrow and Lymphoma refers to cancers that develop in the lymph system. This is a schematic of what cancer looks like. In this case, cancer of the cervix. On the left hand side, you can see normal cells lining an organ and you can see that each cell looks the same. And each nucleus, inside the cell which contains the DNA, looks the same. The first step towards cancer is hyperplasia, where you get a growth in the number of cells. It's a proliferation in the number of cells, and they start to look a little bit atypical. As cancer progresses you get mild dysplasia where the cells start to bunch up on each other and they start to have abnormal nuclei and abnormal shapes. This gets more severe and you develop carcinoma in situ or cancer in place. This is where the cells are growing in an uncontrolled fashion, they look abnormal and their nuclei look abnormal. When cancer starts to invade in metastasis that's when we refer to it as a carcinoma. Let's look at some examples. Here's a histology slide of prostrate cancer or a carcinoma. Prostate cancer is an adenocarcinoma. Here in the slide you can see large, normal glands with an epithelia lining. As you develop low-grade cancer you see that the glands get smaller and bunched up. And then as the cancer gets worse and becomes high-grade, on the right hand side you see lose all the gland architecture. And you just have bunched up cells. This is even clearer in this example of sarcoma. Which in this particular case is a Ewing sarcoma. On the left you see normal connective tissue, with lots of space between the cells. And, on the right, you see how the cancer is just uncontrolled growth. A proliferation of cells. You can see big nuclei there. Cells that don't look normal. There's just a huge difference that is very obvious between the left and the right hand side of the slides. Here is leukemia which again starts in the bone marrow and circulates into the blood. This is an example of acute lymphobastic leukemia. The red blood cells that carry your oxygen are the small doughnuts that you see in the background and they're carrying iron and oxygen to oxygenate your blood. The leukemia cells are just a proliferation of what we call blasts, over growth of cells with big nuclei, big cytoplasm and this is what acute lymphoblastic leukemia looks like. Again, it's a proliferation uncontrolled growth of a certain type of cell that then takes over the blood in body. This is an example of a mantle cell lymphoma. Again, all you see in this picture is an over-growth of cells that are out of shape. They're different shapes and different sizes. And the lymph node, the normal lymph node is totally effaced in this picture. It is nothing but cancer cells. And they start in the lymph node so they are called lymphoma. This ends our section on cancer terms and definitions where we explained what cancer is, where it starts, and gave you some examples of what cancer looks like as it starts in those various organs. We are now going to move on and talk about the instance of some of these cancers.
