**2. What is cancer?**

buccal cavity, pharynges, oropharyngeal, laryngeal, nasopharyngeal, hypopharyngeal, etc., and respiratory tract and finally lung cancers. It was Professor Ross of London University who developed oral cancer drug called melphalan (phenylalanine moiety is the carrier for the nitrogen mustard) to treat pharyngeal carcinoma [1]. Melphalan cross-links both strands of DNA shutting off genes. Statistics is worst for smokers. Over 155,700 Americans died of lung cancer last year and over 222,500 will be diagnosed this year. Compare the US mortality, the worldwide figure is ten times as high. While squamous cell carcinoma is responsible for causing oral cancer, adenocarcinoma is one of the deadliest forms of lung cancers. Most patients

For years, we have been trying to answer three important questions: What is cancer? What causes cancer? And how could we diagnosed treat and prevent cancer. For this chapter, I have divided my presentation in three parts. First, I will provide some historical background; second, I will describe how efforts are being made to develop novel drugs to treat cancer; and

Today, we must tell all smokers in the world that tobacco smoking whether it is the regular cigarette or e-cigarette or nicotine patch or the use of smokeless tobacco, and all tobacco modifications contains nicotine, and it is the nicotine which causes oral and lung cancers. If you are diagnosed with lung cancer, you are most likely to die within 5 years. Tobacco companies have known this fact for more than half a century. In the late 1930s*,* German scientists discovered the fact that tobacco tar causes lung cancer [2]. When Adolf Hitler was elected as the Chancellor of Germany, he authorized 100,000 Deutsch Marks to a science research institute in Munich to isolate and identify all components of tobacco tar which causes lung cancer. He ordered all his uniform officers including pregnant women not to smoke tobacco. These facts are still available in the National archive. Tobacco companies are aware of these facts. For the past 60 years, tobacco companies have lied to us. No one was spending more money on tobacco research than tobacco companies themselves and yet when they confirmed German's finding in early 1960s that smoking causes lung cancer, they hid the fact from general public. For almost 50 years, the greedy tobacco companies exposed millions of smokers around the world with thousands of deadly chemicals with disastrous consequences. Up to this time, more than 6000 toxic chemicals have been isolated and identified from tobacco tar and 60 of those chemicals are deadly and known to cause cancer. The main constituent of tobacco tar nicotine is one of the most addictive chemicals isolated and is probably more addictive than opium. In India, the second most populous nation on Earth, last year, of the 1 million people who died of cancer, almost a quarter million died of lung cancer. Last year alone, about 3 million people died of lung cancer around the world. By the year 2020, smoking will most likely kill about 10 million people worldwide. Most smokers will prematurely die in their middle ages, cutting 20–25 years from their life expectancy. If we examine the death rate during the last 48 years, from 1950 to 1998, you will be shocked to learn that about 50 million men and

die within 5 years of their diagnosis. Tobacco smoking kills faster.

34 Prevention, Detection and Management of Oral Cancer

finally, I will share some ethical problems we are facing today.

10 million women died of cancers by tobacco smoking and related illnesses.

The tobacco companies have flooded so much money in the Congressional and Senatorial election campaign, in the US alone, the US senate had voted not to ban tobacco sale to schoolaged teenagers. Greedy tobacco executives won the day and needy millions around the world lost the day. Now, tobacco companies will be exporting over 150 billion cigarettes per year to Cancer is a very ancient disease. The early Greek coined the term cancer. They thought that this unusual disease spread like a crab so they were the first to call it a cancer or crab. The answer to the first question is that cancer is the abnormal growth of the normal cells due to accumulation of mutations over lifetime.

Our body is made of about 100 trillion cells. These cells are constantly being replaced by similar young fresh cells. For example, your white blood cells (WBCs) live for about 120 days. They are replaced by other white blood cells. Liver cells make more liver cells and replace old liver cells with new liver cells; lung cells make new lung cells. When this normal cell regulation breaks down, liver cells do not produce liver cells; they produce altered cells called mutant cells. Mutation is caused by exposure to radiations, chemical pollutions, viral infection, or genetic inheritance. The changed cells grow much faster than the normal cells and they form a lump, we call it a tumor. As tumor grows, it spreads over to the nearby blood circulating vessels. When tumor grows over these vessels, it draws more nourishment than the normal cells. Some of the tumor cells break off and split and plunge in the blood stream. These live tumor cells flow in the blood stream and travel wherever the blood goes. If the blood goes to the brain, the free floating tumor cells deposit in the brain and start growing as the brain tumors called metastasized cells. Although the cancer may have started in the lungs from smoking, it may spread to the brain or to other organs of our body. Only cancer cells spread this way; we call these migratory deposits metastasized cells, and only metastasized cells invade neighboring organs causing spread of cancer. We have no cure against metastasized cancers.

How many kinds of cancers do we have? There is a cancer for every tissue type in our body. There are 220 types of tissues in our body. Every tissue type in our body can suffer from cancer because every tissue in our body is replaced cells by cells with younger cells; they can either be replaced by normal cells in healthy people or they can also be replaced by abnormal or mutated cells when we get cancer. Would you believe that even your bones are being replaced? You could also get bone cancer.
