The dread and fear that can come with a cancer diagnosis have their roots in its killer nature: It's the No. 2 cause of death in Americans, second only to heart disease, according to the Centers for Disease Control and Prevention. Even when diagnosed early and attacked with the latest treatments, it still has the power to kill.
To help raise money to find cures and treatments for cancer patients, the "Stand Up to Cancer" telethon will air on ABC, NBC and CBS and other networks and cable stations starting at 8 p.m. ET tonight. The telethon will feature a host of celebrity guests, including George Clooney, Denzel Washington, Renee Zellweger and Will Smith.
"'Stand Up To Cancer' represents collaborative efforts" to provide funding for cancer research, Dr. Len Lichtenfeld, deputy chief medical officer of the American Cancer Society, told MyHealthNewsDaily.
"We would not be where we are if basic and clinical science wasn't funded," Lichtenfeld said. "Basic science teaches us about mechanisms, about how drugs may be effective, and we take that info and put it into a clinic to find out whether or not those new ideas work in cancer treatment."
While there are many successful treatments today that didn't exist just a couple decades ago, a wholesale "cure for cancer" remains elusive for many reasons. There are more than 100 types of cancer, characterized by abnormal cell growth. There are many different causes, ranging from radiation to chemicals to viruses; an individual has varying degrees of control over exposure to cancer-causing agents.
Cancer cells, and how they grow, remain unpredictable and in some cases mysterious. Even after seemingly effective treatments, crafty cancer cells are able to hide out in some patients and resurface.
About $200 billion has been spent on cancer research since the early 1970s, and the five-year survival rate for all people diagnosed with cancer in the U.S. has risen from about 50 percent in the 1970s to 65 percent today.

1. Lung and bronchial cancer:
Lung and bronchial cancer is the top killer cancer in the United States. Smoking and use of tobacco products are the major causes of it, and it strikes most often between the ages of 55 and 65, according to the NCI. There are two major types: non-small cell lung cancer, which is the most common, and small cell lung cancer, which spreads more quickly. More than 157,000 people are expected to die of lung and bronchial cancer in 2018.
2. Colon and rectal cancer:
Colon cancer grows in the tissues of the colon, whereas rectal cancer grows in the last few inches of the large intestine near the anus, according to the National Cancer Institute. Most cases begin as clumps of small, benign cells called polyps that over time become cancerous. Screening is recommended to find the polyps before they become cancerous, according to the Mayo Clinic. Colorectal cancer is expected to kill more than 51,000 people in 2010.

3. Breast Cancer:
Breast cancer is the second most common cancer in women in the United States, after skin cancer, according to the Mayo Clinic. It can also occur in men – there were nearly 2,000 male cases between 2003 and 2008. The cancer usually forms in the ducts that carry milk to the nipple or the glands that produce the milk in women. Nearly 40,000 people are expected to die from breast cancer in 2010, according to the NCI.
4. Pancreatic cancer: 
Pancreatic cancer begins in the tissues of the pancreas, which aids digestion and metabolism regulation. Detection and early intervention are difficult because it often progressives stealthily and rapidly, according to the Mayo Clinic. Pancreatic cancer is expected to claim nearly 37,000 lives in 2010, according to the NCI.
5. Prostate cancer:
This cancer is the second-leading cause of cancer deaths in men, after lung and bronchial cancer, according to the NCI. Prostate cancer usually starts to grow slowly in the prostate gland, which produces the seminal fluid to transport sperm. Some types remain confined to the gland, and are easier to treat, but others are more aggressive and spread quickly, according to the Mayo Clinic. Prostate cancer is expected to kill about 32,000 men in 2010, according to the NCI.
6. Leukemia: 
There are many types of leukemia, but all affect the blood-forming tissues of the body, such as the bone marrow and the lymphatic system, and result in an overproduction of abnormal white blood cells, according to the NCI. Leukemia types are classified by how fast they progress and which cells they affect; a type called acute myelogenous leukemia killed the most people – 41,714 – 
7. Non-Hodgkin lymphoma: 
This cancer affects the lymphocytes, a type of white blood cell, and is characterized by larger lymph nodes, fever and weight loss. There are several types of non-Hodgkin lymphoma, and they are categorized by whether the cancer is fast- or slow-growing and which type of lymphocytes are affected, according to the NCI. Non-Hodgkin lymphoma is deadlier than Hodgkin lymphoma, 
8. Liver and antipathetic bile duct cancer: 
Liver cancer is one of the most common forms of cancer around the world, but is uncommon in the United States, according to the Mayo Clinic. However, its rates in America are rising. Most liver cancer that occurs in the U.S. begins elsewhere and then spreads to the liver. A closely related cancer is antipathetic bile duct cancer, which occurs in the duct that carries bile from the liver to the small intestine. 
9. Ovarian cancer: 
Ovarian cancer was the No. 4 cause of cancer death in women between 2003 and 2007, according to the NCI. The median age of women diagnosed with it is 63. The cancer is easier to treat but harder to detect in its early stages, but recent research has brought light to early symptoms that may aid in diagnosis, according to the Mayo Clinic. Those symptoms include abdominal discomfort, urgency to urinate and pelvic pain.