The cancer burden is surging, with an estimated 20 million diagnoses and 9.7 million deaths occurring each year. Despite its prevalence, cancer continues to perplex people worldwide, with many continuing to believe myths, misinformation, or outdated, fearful perceptions. Let’s correct these misunderstandings with facts.
What Is Cancer?
Cancer is a disease. It manifests as abnormal cells that grow uncontrollably and spread to other areas of the body. Unlike healthy cells, which have a limited lifespan, cancer cells are “immortal” by multiplying indefinitely. This uncontrolled growth occurs when genetic mutations damage the systems that regulate cell division and death.
What Is Cancer at the Cellular Level?
The human body contains approximately 37 trillion cells. DNA within each cell contains genetic instructions that control cell division, protein production, and cellular metabolism.
Normal cells divide when necessary, then stop and eventually die in an orderly process. Cancer cells break these rules by dividing endlessly. With their “replicative immortality,” they resist death signals and evade immune detection. These cells also recruit blood vessels to nourish themselves, and they can travel through the bloodstream to form tumors in distant organs. This uncontrolled growth and spread is what distinguishes cancer from healthy tissue.
A Detailed Explanation of the Difference Between Normal and Cancer Cells
Normal, healthy cells divide (mitosis) when the body needs new cells to replace damaged, old, or dead ones. Once divided sufficiently, they receive signals to stop. If a cell is damaged beyond repair, it undergoes apoptosis, wherein the cell self-destructs. This cycle prevents tumors from forming.
As mentioned, cancer cells ignore these rules. They divide continuously and develop resistance to apoptosis, so damaged cells survive when they should die. Cancer cells are also notorious for evading the immune system, which normally eliminates harmful invaders before they cause problems.
In addition, cancer cells alter their environment to ensure their survival. They signal nearby blood vessels to grow toward them, ensuring oxygen and nutrient supply. Most cancer cells also gain the ability to move throughout the body, traveling through the bloodstream to establish tumors in distant locations. This process, called metastasis, transforms localized cancer into systemic disease.
How Does Cancer Develop? The Multi-Step Process
A normal cell does not transform into a cancer cell overnight. Instead, cancer develops through a series of genetic changes that happen over many years.
- In the first step, a cell acquires an oncogene. Oncogenes are mutated versions of normal genes. When they activate, they drive excessive cell division. A person might acquire one from exposure to a carcinogen, like cigarette smoke or asbestos, or they might inherit a mutated gene from a parent.
- In the second step, a cell loses a tumor suppressor gene. The TP53 gene is the most well-known tumor suppressor gene. When DNA damage occurs, it stops cells from dividing. When a cell cannot repair its damage, TP53 triggers the cell to die. However, when TP53 mutates, cells ignore these death signals and keep dividing instead.
- In the third step, genes that repair DNA become damaged. Healthy cells can detect and fix mistakes in DNA. When these repair mechanisms fail, errors accumulate and mutations build up faster, accelerating cancer development.
- In the fourth step, cancer cells reactivate an enzyme called telomerase. Telomeres are protective caps at the ends of chromosomes. Each time a cell divides, telomeres shorten. Normal cells can divide only 50 to 70 times before their telomeres become too short and stop further division. When cancer cells reactivate telomerase, it rebuilds telomeres back to their original length. Because telomeres no longer shorten with each division, cancer cells divide endlessly.
It takes years or decades for a normal cell to become cancerous. For instance, a person might acquire a mutation at age 25 from smoking or sun exposure. While that single mutation does not cause cancer, over the next 30 or 40 years, additional mutations accumulate in that cell and other cells. By age 55 and older, enough mutations have accrued that cancer may develop. Cancer mostly affects older people because mutations build up over a lifetime.
What Are the Main Types of Cancer?
Doctors classify cancers based on the type of cell where they originate:
1. Carcinoma
Carcinomas start in epithelial cells, which line the surface and cavities of the body. These are the most common cancers, accounting for 80 to 90 percent of all cases. Examples include adenocarcinoma (breast, lung, colon, prostate), basal cell carcinoma (most common skin cancer), squamous cell carcinoma (skin, lung, throat), and transitional cell carcinoma (bladder, kidney).
2. Sarcoma
Sarcomas develop in connective tissues like bone, cartilage, muscle, and fat. These cancers are much less common than carcinomas. Osteosarcoma (bone cancer) and leiomyosarcoma (affects smooth muscle cells in the uterus, abdomen, or blood vessels) are examples.
3. Leukemia
Leukemias are cancers of blood-forming cells. Instead of forming solid tumors, leukemia cells multiply rapidly in the bone marrow and spill into the bloodstream, where they outnumber healthy blood cells.
4. Lymphoma
Lymphomas are cancers of lymphoid cells, which are part of the immune system. They typically form tumors in lymph nodes, the spleen, and other lymphoid tissues. Hodgkin lymphoma and non-Hodgkin lymphoma are the two main types.
Understand the difference between leukemia and lymphoma.
5. Myeloma
Myeloma is a cancer of plasma cells in the bone marrow. Plasma cells produce antibodies that fight infection. When myeloma develops, abnormal plasma cells multiply and crowd out healthy blood cells, resulting in anemia, increased infections, and bone damage.
These categories include the cancers that occur most frequently, but hundreds of other specific cancer types exist. Within these main categories and beyond them, cancers behave differently, spread through different pathways, and require different treatment approaches.
What’s the Difference Between Cancer Grade vs. Cancer Stage?
Cancer grading and cancer staging help oncologists determine how serious a cancer is. Many people mistake these terms for one another. Understanding the difference helps patients grasp their diagnosis.
What Does Cancer Grade Mean?
Cancer grade describes how cancer cells look under a microscope compared to healthy cells. It ranges from 1 to 4.
- Grade 1 cancers resemble healthy cells. The cells are well-differentiated, meaning they retain characteristics of normal cells. They grow slowly and have the best outcomes.
- Grade 2 cancers look moderately different from healthy cells. The cells exhibit some abnormal features but still have some resemblance to normal cells. They grow at a moderate rate.
- Grade 3 cancers look very different from healthy cells. The cells are poorly differentiated and have significant chromosomal mutations. They grow rapidly, generate toxic compounds that damage neighboring cells, and may enter the bloodstream. They have worse outcomes than Grade 1 or 2.
- Grade 4 cancers are completely undifferentiated. These primitive cells look nothing like healthy cells and divide very rapidly. Grade 4 cancers are the most aggressive and have the poorest prognosis.
How Do Doctors Determine Cancer Stage?
While grade describes what cancer cells look like, stage describes where cancer is located and how far it has metastasized (spread)..
- Stage I cancer remains localized to the area where it started. It generally responds well to treatment.
- Stage II cancer has grown larger or begun spreading to nearby lymph nodes, but distant spread has not occurred. It is still in the region where it originated.
- Stage III cancer or locally advanced cancer has grown deeper into surrounding tissues and reached nearby lymph nodes, but not yet to distant organs.
- Stage IV cancer has metastasized to distant organs or parts of the body far from the original cancer site. Also referred to as metastatic cancer, it is the most advanced form of the disease, accounting for over 90 percent of all cancer deaths.
How Do Cancer Grade and Stage Affect Diagnosis?
These two factors work differently but are equally important. For example, patients with Grade 1, Stage IV cancer have slow-growing cells that have metastasized to distant organs. In many cases, these patients have a better chance of living longer if they receive treatments that aim to manage the disease and improve quality of life (QoL) rather than trying to “cure” it. Remission is still possible with alternative cancer treatments and precision oncology approaches that target the specific mutations.
To cite another example, cancer patients with Grade 4, Stage I disease have aggressive cells in one location. These patients typically undergo more conventional treatments, such as surgery and chemotherapy, to prevent the cancer from spreading. Doctors may also suggest alternative approaches, including immunotherapy and precision oncology, depending on the patient’s health and specific tumor characteristics.
In other words, why two patients receive different treatment plans depends on the grade of their cancer cells and how far the cancer has spread.
What Causes Cancer? Understanding Cancer Risk Factors
In many cases, cancer occurs through a combination of the following:
1. Lifestyle
Tobacco
Smoking damages the DNA in lung cells, yet 1.25 billion adults continue to smoke despite being one of the leading, preventable causes of cancer.
Tobacco smoke contains more than 7,000 chemicals, including at least 70 known carcinogens. Secondhand smoke also increases cancer risk, especially for lung cancer.
Alcohol Consumption
Alcohol consumption increases the risk of several life-threatening cancers, including liver, colon, esophageal, breast, and rectum. The more someone drinks, the higher their risk becomes. Even moderate drinking raises cancer risk.
Obesity
Obesity is a leading, preventable cause of cancer, ranked alongside smoking as a top risk factor. Excess fat tissue produces hormones and inflammatory molecules that stimulate cell growth. It increases the risk of numerous cancers, including but not limited to breast cancer, endometrial cancer, colon cancer, and pancreatic cancer.
Poor Diet and Physical Inactivity
Diets high in processed food and added sugar, while lacking vegetables and whole grains, raises cancer risk by promoting inflammation and damaging cells. Poor nutrition also contributes to obesity, which itself increases cancer risk.
Regular exercise paired with a diet rich in plant-based foods can strengthen the immune system, reduce inflammation, and minimize the risk of cell damage.
2. Occupational and Environmental Exposures
Asbestos
Asbestos exposure can lead to mesothelioma or lung cancer development. Workers in construction, shipbuilding, insulation manufacturing, and automotive repair are some of the most at risk. Military veterans are also vulnerable, particularly Navy personnel who worked in shipyards, engine rooms, and with insulation, boilers, or brakes.
When asbestos deteriorates, tiny fibers become airborne. Inhaled asbestos fibers lodge in lung tissue and cause chronic inflammation. This inflammation can lead to mesothelioma or lung cancer decades after exposure. Even low-level environmental exposure near asbestos mines or in old buildings constructed before asbestos was regulated can pose risks.
Radon and Industrial Chemicals
Radon is a radioactive gas that accumulates in basements and crawl spaces. It increases lung cancer risk, especially among smokers. Exposure to certain industrial chemicals like benzene and vinyl chloride also heightens cancer risk.
Air Pollution
Fine particulate matter, or PM2.5, penetrates deep into the lungs and triggers inflammation. This chronic inflammation injures cells and can lead to DNA damage over time.
People living in areas with high air pollution breathe these particles every day. The cumulative exposure increases the risk of lung cancer.
Ultraviolet Radiation
Ultraviolet (UV) radiation from natural sunlight and artificial tanning beds damages DNA in skin cells. They are the main cause of certain types of melanoma and skin cancer. The damage accumulates over a lifetime of exposure.
3. Infections
Infections from certain viruses and bacteria increase cancer risk. To be specific:
- Human papillomavirus (HPV) causes most cervical cancers
- Chronic Hepatitis B and hepatitis C viruses cause liver cancer
- Helicobacter pylori bacterium increases stomach cancer risk
- Human immunodeficiency virus (HIV) weakens the immune system and increases the risk of several cancers
4. Inherited Genetic Factors
Some people inherit mutations that raise their cancer risk. For example, mutations in the BRCA1 and BRCA2 genes increase the risk of breast and ovarian cancer. Another example involve men and women with Lynch syndrome, stemming from mutations in DNA repair genes, who have a high lifetime risk of colorectal cancer and other malignancies. Families with BAP1 mutations also have higher rates of uveal melanoma and renal cell carcinoma. These examples show the link between inherited cancer syndromes and multiple cancer types.
However, inherited mutations account for only 5 to 10 percent of cancer diagnoses. Most result from acquired mutations during a person’s lifetime.
What if the Cause of Cancer Is Unknown?
Not all cancers have an identifiable cause.
Some people develop the disease without any known risk factors. They may have never smoked, avoided sun exposure, ate nutritiously, and exercised regularly, yet cancer still developed.
Researchers do not fully understand why this phenomenon happens in some cases. Cancer can result from random mutations that occur during normal cell division. These spontaneous errors happen by chance and are inevitable. This unpredictability is one reason cancer is so difficult to prevent, and why screening tests and early detection are so important, even for people with low risk factors.
What Are the Signs and Symptoms of Cancer?
Some warning signs apply across many cancer types:
- Persistent fatigue
- Unexplained loss of appetite and weight loss
- Persistent fevers or infections
- Persistent pain without an obvious cause
- Persistent cough, hoarseness, or difficulty swallowing
- Persistent abdominal discomfort
- Persistent diarrhea or constipation
- Blood in stool, urine, or vomit
- Unusual bleeding or bruising
- Lumps or swelling in the neck, armpit, or groin
- Changes in skin appearance, including new moles or changes to existing moles
- Persistent heartburn or difficulty eating
These signs and symptoms vary depending on the cancer type and location. For instance, lung cancer may cause persistent coughing and chest pains, while colon cancer may cause changes in bowel habits.
Different cancers have different warning signs. Some may not even cause symptoms until the disease is in an advanced stage. Screening tests help detect cancer early, often before symptoms appear, when it is easiest to treat, boosts survival rates, and may prevent cancer by identifying pre-cancerous cells.
Why Cancer Requires Personalized Treatment Plans
Specialized cancer treatment centers have access to cutting-edge technology and multidisciplinary teams including oncologists, surgeons, pathologists, and supportive care specialists. For example, here at New Hope Unlimited, we implement immunotherapy, precision oncology, and supportive care strategies to address the physical and emotional sides of cancer. Unlike many institutions that still classify immune-based treatments as “emerging” or “experimental,” we use established research and international clinical data to apply these treatments safely and effectively.
Taking the Next Step: Talk to a Precision Oncology Provider Near You
Receiving a cancer diagnosis changes your life. Fear, anger, sadness, and anxiety are all normal responses.
However, a cancer diagnosis is not a death sentence. Survival rates have improved dramatically in the last decade. Many cancers, when found early, are highly treatable. Even advanced cancers respond to modern treatments, allowing patients to live longer with good quality of life.
The most important steps after diagnosis are seeking medical evaluation at a qualified cancer center, understanding your cancer type and its severity, developing a comprehensive treatment plan, and prioritizing your quality of life.
If you have cancer, or perhaps researching treatments for a loved one, let New Hope Unlimited guide you through evidence-based treatment options tailored to your cancer type, grade, stage, symptoms, and other factors. Schedule a consultation today.
FAQs About Cancer
What is the difference between benign and malignant tumors?
Benign tumors are noncancerous, slow-growing, and do not spread to other parts of the body, while malignant tumors are cancers that grow rapidly and can metastasize to distant organs.
Is cancer hereditary?
It can be, but inherited mutations are responsible for only 5 to 10 percent of all cancer diagnoses.
Does everyone exposed to carcinogens develop cancer?
No. While carcinogens increase the risk of developing cancer, exposure does not mean a person will definitely get the disease. One’s risk also depends on factors like the amount and duration of exposure, genetics, and individual cell repair capabilities.
How many types of cancer are there?
More than 200 different types.
What is the difference between cancer screening and cancer diagnosis?
Screening tests help detect cancer, often before symptoms appear. A diagnosis confirms cancer through biopsy and imaging, after symptoms or screening results raise suspicion.
Do all cancers respond to the same treatments?
No. Cancer is an umbrella term for 200+ different diseases, each with unique genetic mutations, behaviors, and treatment needs.
Is cancer preventable?
Some cancers can be prevented by avoiding risk factors like smoking, excessive sun exposure, and alcohol consumption. However, some cancers develop regardless of lifestyle choices.
What does remission mean?
Complete remission means cancer is no longer detectable through tests and imaging, while partial remission means some cancer persists but has shrunk significantly.
Is cancer always fatal?
No. Many cancers are highly treatable, especially when caught early.
What causes cancer to spread?
Cancer cells can evolve and gain the ability to separate from tumors, travel through blood and lymph vessels, and settle in distant organs. This process is called metastasis.
Can cancer come back after treatment?
Unfortunately, it can. Cancer can recur in the same location or in distant organs, which is why ongoing monitoring with imaging and blood tests continues after treatment ends.
Can you catch cancer from someone else?
No. Cancer is not contagious. However, some infections that increase cancer risk, like HPV and hepatitis, can spread between people.
What should I do if I have cancer symptoms?
See a healthcare provider immediately. Do not wait for symptoms to resolve. Early evaluation and diagnosis improve treatment outcomes significantly.