Cancer cell

Cancer cells are cells that divide continually, forming solid tumors or flooding the blood or lymph with abnormal cells. Cell division is a normal process used by the body for growth and repair. A parent cell divides to form two daughter cells, and these daughter cells are used to build new tissue or to replace cells that have died because of aging or damage. Healthy cells stop dividing when there is no longer a need for more daughter cells, but cancer cells continue to produce copies. They are also able to spread from one part of the body to another in a process known as metastasis.^[1]

Classification

There are different categories of cancer cell, defined according to the cell type from which they originate.^[2]

• epithelial
  in origin, beginning in a tissue that lines the inner or outer surfaces of the body.
• blood cells, most commonly in the bone marrow
  .
• myeloma, derived from cells of the immune system
  .
• Sarcoma, originating in connective tissue, including fat, muscle and bone.
• Central nervous system, derived from cells of the brain and spinal cord.
• Mesothelioma, originating in the mesothelium; the lining of body cavities.

• 
  Carcinoma
• 
  Leukaemia
• 
  Lymphoma
• 
  Myeloma
• 
  Sarcoma
• 
  Mesothelioma

Histology

Cancer cells have distinguishing

Main article:

Malignant tumors can invade other organs, spread to distant locations (metastasis

) and become life-threatening.

More than one mutation is necessary for carcinogenesis. In fact, a series of several mutations to certain classes of genes is usually required before a normal cell will transform into a cancer cell.[5]

Damage to

DNA transcription, making age another risk factor. Oncoviruses can cause certain types of cancer, and genetics are also known to play a role.^[6]

Stem cell research suggests that excess

stem cells into cancer cells.^[7] However, a lack of particular co-stimulated molecules that aid in the way antigens react with lymphocytes can impair the natural killer cells' function, ultimately leading to cancer.^{[8][failed verification}

]

DNA repair and mutation

When a cell is deficient in the capacity to

germ-line. However, DMC1 is also expressed in various cancer cell lines including cervical, breast, and lymphoma cancer cell lines.^[9] Expression of meiotic DNA repair genes such as DMC1 may promote tumor cell growth by dealing with endogenous DNA damage within the tumor, and may also diminish the effectiveness of anticancer therapy, such as radiation therapy.^[9]

Pathology

Cells playing roles in the immune system, such as

macrophages detect and kill cancer cells.^[10]

Discovery

Early evidence of human cancer can be interpreted from

hominin cancer.^[12]

The understanding of cancer was significantly advanced during the

skull).^[17][18]

Telomerase

Cancer cells have unique features that make them "immortal" according to some researchers. The enzyme telomerase is used to extend the cancer cell's life span. While the telomeres of most cells shorten after each division, eventually causing the cell to die, telomerase extends the cell's telomeres. This is a major reason that cancer cells can accumulate over time, creating tumors.

Cancer stem cells and drug resistance

Scientists have discovered a molecule on the surface of tumors that appears to promote drug resistance—by converting the tumor cells back into a stem cell-like state.

When the tumor cells began to exhibit drug resistance, the cells were simultaneously transforming into a stem cell-like state, which made them impervious to the drugs. It appeared that the treatment itself was driving this transformation by activating a specific molecular pathway. Luckily, several existing drugs, such as Bortezomib for example, can attack this pathway and reverse the cellular transformation, thus 're-sensitizing' the tumor to treatment.^[19][20][21]

Treatment

In February 2019, medical scientists announced that

cancer cells and, after being irradiated with light (a process called photodynamic therapy), destroy the cancer cells.^[22][23]

See also

• Apoptosis
• BRCA1
• Carcinogen
• Carcinogenesis
• Epidemiology of cancer
• Oncology
• Tumour heterogeneity

References

1. ^ "National Cancer Institute: is this cancer?". 2007-09-17. Retrieved 1 August 2016.
2. ^ "Histological types of cancer - CRS - Cancer Research Society". www.crs-src.ca. Archived from the original on 2017-08-27. Retrieved 2016-08-02.
3. ^ Baba AT, Câtoi C (2007). "Comparative Oncology". Tumor Cell Morphology. The Publishing House of the Romanian Academy.
4. S2CID 29052588
   .
5. S2CID 22975880
   .
6. ^ What causes cancer? : Cancer Research UK : CancerHelp UK. Cancerhelp.org.uk (2010-07-15). Retrieved on 2010-12-01.
7. ^ Too much SP2 protein turns stem cells into 'EVIL TWIN' cancer cells. Sciencedaily.com (2010-10-27). Retrieved on 2010-12-01.
8. ^ ^{a b} "The Innate Immune System: NK Cells". Community College of Baltimore County. Archived from the original on 2010-07-27. Retrieved 2010-12-01.
9. ^
   PMID 35251135
   .
10. ^ The Adaptive Immune System: Ways That Antibodies Help to Defend the Body - Antibody-Dependent Cellular Cytotoxicity (ADCC) Archived 2010-07-27 at the Wayback Machine. Student.ccbcmd.edu. Retrieved on 2010-12-01.
11. S2CID 10492262
    .
12. ISSN 1996-7489
    .
13. ^ "History of cancer" (PDF). University of Bergen. 23 March 1999. Archived from the original (PDF) on 2012-03-14. Retrieved 2010-11-30.
14. PMID 11920227
    .
15. PMID 22033191
    .
16. ISBN 978-1-4391-0795-9
    . Retrieved 6 September 2011.
17. doi:10.1001/jama.1923.02640460019007
    .
18. PMID 9269106
    .
19. PMID 33588867
    .
20. ^ Holden A (23 April 2014). "Tumor Cells Become Drug Resistant by Reverting to a Stem Cell-Like State".
21. PMID 24747441
    .
22. EurekAlert!
    . Retrieved 3 February 2019.
23. PMID 30552796
    .

Further reading

• Schwarzer, K.; Foerster, M.; Steiner, T.; Hermann, I. M.; Straube, E. (2010). "BCG strain S4-Jena: An early BCG strain is capable to reduce the proliferation of bladder cancer cells by induction of apoptosis". Cancer Cell International. 10: 21.
  PMID 20587032
  .

External links

• The History of Cancer Archived 2015-12-12 at the Wayback Machine. Cancer.org. Retrieved on 2010-12-01