Normally, human cells grow and divide to form new cells and as the cells grow old or are damaged, they are replace with new cells. When this order of cell cycle breaks down and cells proliferate abnormally, they form tumors that can be cancerous or non-cancerous. Cancer is still a significant concern for public health as it can start anywhere in the human body, where it grows and spreads uncontrollably. Cancer cells are invasive and can invade nearby tissues or travel to distant places in the body to form new tumors, also called metastasis (1).
This article covers key points in which normal cells differ from cancerous cells (2,3).
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Cancer cells
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Normal cells
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| Cell division |
| Uncontrolled and deregulated growth |
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| Cell division and growth is tightly regulated |
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| Cell death/repair |
| Damaged cells that cannot be repaired remain alive and proliferate abnormally |
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| Cell damage leads either to repair or cell death |
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| Cell communication |
| Cells behave irresponsively of regulating signals coming from other cells |
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| Cell behaviour is regulated by cell-cell contact and communication |
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| Appearance under the microscope |
| Higher variability in cell size, darker appearance of the nucleus |
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| Uniform appearance within the same cell type |
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| Spread |
| Capacity to leave the tissue of origin, enter blood or lymphatic vessels to reach other tisseues and colonize them |
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| Adhesion molecules prevent cells from detaching from their designed place and leave their tissue of origin |
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| Maturation |
| They are rather undifferentiated or less differentiated that their normal counterpart |
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| They reach maturity and differentiate |
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| Immune system invasion |
| They escape immune detection and inhibit immune response |
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| The immune system recognizes and removes damaged and dead cells |
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| Blood supply |
| The formation of new vessels called neoangiogenesis is a hallmark of cancer |
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| Angiogenesis usually occurs as part of the normal development of a tissue |
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References
- Breitenbach M, Hoffmann J. Editorial: Cancer Models. Front Oncol. 2018 Oct 3;8:401. doi: 10.3389/fonc.2018.00401. PMID: 30338241; PMCID: PMC6178941.
- Zhu S, Wang J, Zellmer L, Xu N, Liu M, Hu Y, Ma H, Deng F, Yang W, Liao DJ. Mutation or not, what directly establishes a neoplastic state, namely cellular immortality and autonomy, still remains unknown and should be prioritized in our research. J Cancer. 2022 Jul 4;13(9):2810-2843. doi: 10.7150/jca.72628. PMID: 35912015; PMCID: PMC9330459.
- Chen P, Hsu WH, Han J, Xia Y, DePinho RA. Cancer Stemness Meets Immunity: From Mechanism to Therapy. Cell Rep. 2021 Jan 5;34(1):108597. doi: 10.1016/j.celrep.2020.108597. PMID: 33406434; PMCID: PMC7839836.
