What’s the difference between cancer cells vs. normal cells in the human body? Cancer cells do not act the same as normal cells. They do not develop into mature cells with specific tasks. Everyone has trillions of cells within their bodies, and cancer can start in any of them.

Cancer Cells vs. Normal Cells

Cancer occurs when some cells in the body grow uncontrollably and spread. Under normal circumstances, cells grow and multiply forming new cells as necessary. Old or damaged cells die and are replaced by new ones. Cancer cells are damaged or abnormal cells that do not follow this normal process. Here’s a deeper look into cancer cells vs. normal cells and how they compare.

Cellular Growth

Growth is a major factor in the difference between cancer cells vs. normal cells. Due to gene mutations, cancer cells do not receive the signals or communication that normal cells do. Normal cells receive signals that they should cease dividing or expire. Cancer cells ignore these signals, continuing their growth. They grow so quickly that cells cannot mature.

Normal cells stop dividing when coming into contact with other cells. That is not the case with cancer cells. Normal cells stay within their own areas of the body and do not move around. They secrete substances causing them to stick together. Cancer cells do not make these sticky substances. So, they move around the body.

Cell Lifespan

Normal cells have a standard lifespan. That is not the case with cancer cells. Rather than die off as a normal cell does after reaching its lifespan, cancer cells continue to grow and spread. That spread is referred to as metastasis.

Keep in mind that metastatic cancer always refers to the site of the original cancer. For example, breast cancer cells may spread to the bone or brain. While other parts of the body are affected, it is still breast cancer.

Blood Supply

Cancer cells have the same needs as normal cells, in that they require a blood supply to provide oxygen and nutrients for growth. However, some cancer cells do not rely on the same kinds of nutrients as normal cells. Certain cancer cells derive energy from nutrients differently than normal cells.

Tumor Growth

Continuously growing cancer cells eventually form a tumor. Nearby blood vessels supply the tumor with the oxygen and nutrients needed for growth. That growth requires more blood to supply the tumor which the cancer cells provide by signaling the tumor to produce more blood vessels. This process is known as angiogenesis.

Not all types of cancer involve tumors. There are cancer cells affecting the blood such as leukemia.

Immune System Function

It is the immune system’s job to rid the body of damaged or abnormal cells and replace them with normal, healthy cells. Cancer cells try to evade the immune system. These cells may fool the immune system into helping them survive.

Cancer cells might get the immune system to protect them by “persuading” it not to attack tumors. They can also secrete chemicals that make immune cells coming to the site of the tumor ineffective.

How Are Cancer Cells Identified?

Pathologists identify the type of cancer by viewing these cells under a microscope. Types of cancer cells have a different appearance.

For instance, small cell cancers — such as small cell lung cancer or prostate cancer — are smaller than normal cells. Large cell cancers — such as lymphoma or lung cancer — look bigger. Some uterine, kidney and ovarian cancers have cells in which the inside appears clear.

A squamous cell is flat while an adenocarcinoma resembles a gland. An anaplastic cell looks so abnormal that determining exactly where the cancer cells originated is often difficult.

Normal cells look like the cells of their specialization. A pathologist would not mistake a kidney cell for a colon cell. When cancer cells are poorly differentiated, that means they do not resemble normal cells at all.

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For more than 70 years, Yosemite Pathology and Precision Pathology has advanced anatomic pathology in the Western United States. Today, our practice encompasses more than 20 board-certified anatomic pathology specialists serving hospitals and patients with a broad range of specialties in both anatomic and clinical pathology, supplemented by targeted subspecialty training.

We have the training and experience to help you. For more information about our services, contact us today.

Jane Meggitt’s work has appeared in dozens of publications including USA Today, Zack’s, Financial Advisor, nj.com, The Houston Chronicle and The Nest. She is a graduate of New York University.


Canadian Cancer Society – How cancer starts, grows and spreads

National Cancer Institute – What is Cancer?

Cancer.net – What is Metastasis?

Mayo Clinic – Small cell, large cell cancer – What this means