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Understanding the difference between normal body cells and cancer cells


Normal cells vs Cancer cells

Cancer is known as abnormal growth of normal cells of our body. This transformation of normal to an abnormal cell can happen due to many reasons. Genetic changes like DNA break, DNA damage or genetic defects in a cell are the major cause of the cancer1.

Irrespective of the reason, when cells lose control over its growth or its own repair system and start growing uncontrollably then they become cancer cells. Unlike normal cells which can stop its growth through their own cell signaling process and also repair themselves in the case of damage, cancer cell lacks these two properties. 

In the case of Blood cancer, the cancer cells produce many of these faulty cells and spread throughout the body1,2. It has been enormous challenges for researchers to find out what caused the normal body cells turn in to cancer cells.

How they become cancer cells?

To understand the difference between normal cells and cancer cells, researchers have investigated around 45,000 genes inside the cells and identified around 500 genes are significantly different in cancer cells compared to normal cells. Therefore, any of these changes in the genes or combination of genes can cause cancer 3.
The changes inside in the DNA of cells can happen for many reasons. It can be inherited from the parents or it can happen because of certain chemical exposure during the life time of an individual. It is also possible even due to some viral or bacterial infection2. Viral infection contributed almost 15-20% of total human cancers 4. These viruses are called oncogenic viruses.

There are total five human viruses that are majorly involved in more than twenty types of cancers in the patients with weakened immune system. 

These viruses are; Human T-cell leukemia virus (HTLV-1) Hepatitis C virus (HCV) Human papillomavirus (HPV), Hepatitis B virus (HBV), Epstein–Barr virus (EBV), Kaposi's sarcoma-associated herpesvirus (KSHV)/human herpes virus 8 (HHV8) and Human immunodeficiency virus type 1 (HIV-1)4,5.
On the contrary, bacterial infection is not generally considered as a cause of cancer. However, there is some increasing amount of evidence showed that some bacteria such as Helicobacter pylori can cause mucosal-associated lymphoid tissue (MALT) lymphomas.

In addition, there are few other bacteria in the gut and other regions like Escherichia coli, Citrobacter freundii, Chlamydia trachomatis etc have shown some evidence of causing cancer in the gut region and reproductive system respectively 6. Nonetheless, more evidence is required to establish this theory. Depending on the type of cancer, all these transformations inside the cells do not happen in few days, the genetic changes that affect many generations of cells which eventually present cancer2,7.

Do they look different?

Cancer cells also look very different than normal cells under the microscope. Structurally they look bigger or smaller than normal cells depending on the type of cancer8,9. Additionally, nucleus inside the cells also looks very different in cancer cells compared to normal cells1. These structural changes affect the morphology and behavior of the cell.

It has also been observed that cancer cells lose some of the important receptor molecules on the outer surface of the cell which gives a necessary signal to the neighboring cells when to control their growth and replication. Therefore, cancer cells grow without any control and repair system2. Through investigation, it is found that cancer cells are more acidic than normal cells and that could be one reason why normal cells cannot survive the cancer environment10.

How can we treat them?

There are a couple of options to treat these cells. Depending on the size of the tumor, it can be removed through surgery to get rid of a major mass of cells. However, it does not assure the complete removal of all the cells from the body.

There is also radiation or chemotherapy available which will help to kill the cancer cells with different dosage of radiation or drugs with some side effects 11. There are quite a few treatment options that have become increasingly popular depending on the type of cancer.

They are immunotherapy, targeted therapy, hormone therapy, stem cells therapy and precision medicine based on the genetic makeup of the patients 11,12. Most of the cases, patients are treated with the combination of these treatments13. However, it is also possible to be treated with only one type of treatment.

Like the disease, cancer treatment is also evolving and different new treatment options are also been investigated by cancer researcher. In this regard, please refer to our website Our website will provide more articles and videos related to the most recent and advanced treatment options for different types of cancer. 

Writer: Dr. Roy Upal




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4. McLaughlin-Drubin ME, Munger K. Viruses associated with human cancer. Biochim Biophys Acta. 2008 Mar;1782(3):127-50. doi:.1016/j.bbadis.2007.12.005. Epub.2007 Dec 23. Review. PubMed PMID: 1820157




8. Kolch W, Halasz M, Granovskaya M, Kholodenko BN. The dynamic control of signal transduction networks in cancer cells. Nat Rev Cancer. 2015 Sep;15(9):515-27.doi: 10.1038/nrc3983. Epub 2015 Aug 20. Review. PubMed PMID: 26289315.

9. Suresh S. Biomechanics and biophysics of cancer cells. Acta Biomater. 2007Jul;3(4):413-38. Epub 2007 May 30. Review.PMID: 17540628.

10. Griffiths JR. Are cancer cells acidic? British Journal of Cancer. 1991;64(3):425-427.


12. Scott AM, Wolchok JD, Old LJ. Antibody therapy of cancer. Nat Rev Cancer. 2012 Mar 22;12(4):278-87. doi: 10.1038/nrc3236. Review. PubMed PMID: 22437872.

13. Bang YJ, Van Cutsem E, et al . Trastuzumab in combination with chemotherapy versus chemotherapy alone for treatment of HER2-positive advanced gastric or gastro-oesophageal junction cancer (ToGA): a phase 3, open-label, randomized controlled trial. Lancet. 2010 Aug 28;376(9742):687-97. PMID: 20728210.

Topics: cancer

Dr. Upal Roy

Written by Dr. Upal Roy

Upal Roy is a part time faculty at James Madison University, Virginia USA, and an entrepreneur. He has obtained his Ph.D. in Microbiology and has been doing research on infectious diseases and drug discovery for last twelve years. His research has shown how drug formulation can be improved to be more sustained and therapeutically effective than the conventional drug that are available in the market.