study

1. Structure and Characteristics of
Normal and Cancerous cells

2. Objectives
At the end of this session students will be able to :
• Explain the normal cell structure
• Detail on cell cycle
• Enlist the characteristics of normal cells
• Define Cancer
• Describe Progression of cancer
• Explain benign and malignant tumor and their differences
• Differentiate between Normal cells and cancer cells

3. Cell Structure

4. Cell Cycle

5. Characteristics of Normal cells
• These ‘normal’ cells act as the body’s basic building blocks.
• Normal cells control their growth using external signals, meaning
they only grow and divide when required.
• They undergo programmed cell death (apoptosis) as part of
normal development, to maintain tissue homeostasis, and in
response to unrepairable damage.
• They ‘stick together’ by maintaining selective adhesions that they
progressively adjust which ensures they remain in their intended
location.
• Normal cells differentiate into specialized cells with specific
functions meaning they can adopt different physical
characteristics despite having the same genome.

6. What is CANCER?
• An uncontrolled division of abnormal cells in a part of the
body is called cancer.
• Abnormal cells divide without control and can invade nearby
tissues.
• Loss of Cell-cycle Control.
• Before a cell divides, the DNA is checked to make sure it
has replicated correctly. (If DNA does not copy itself
correctly, a gene mutation occurs.

8. Essential alterations in cell physiology that
characterized malignancy
In 2000 cancer biologists Robert Weinberg and Douglas
Hanahan published an article entitled "The Hallmarks of
Cancer.“
• Self-sufficiency in growth signals: cancer cells acquire an
autonomous drive to proliferate - pathological mitosis - by
virtue of the activation of oncogenes such as ras or myc.
• Insensitivity to growth-inhibitory (antigrowth) signals: cancer
cells inactivate tumor suppressor genes, such as Rb, that
normally inhibit growth.
• Evasion of programmed cell death (apoptosis): cancer cells
suppress and inactivate genes and pathways that normally
enable cells to die.

9. Essential alterations in cell physiology that
characterized malignancy
In 2000 cancer biologists Robert Weinberg and Douglas
Hanahan published an article entitled "The Hallmarks of
Cancer.“
• Limitless replication potential: cancer cells activate specific
gene pathways that render them immortal even after
generations of growth.
• Sustained angiogenesis: cancer cells acquire the capacity to
draw out their own supply of blood and blood vessels - tumor
angiogenesis.
• Tissue invasion and metastasis: cancer cells acquire the
capacity to migrate to other organs, invade other tissues, and
colonize these organs, resulting in their spread throughout
the body.

10. What is Tumor?
• A tumor is an abnormal growth
of body tissue. Tumors can be
cancerous (malignant) or
noncancerous (benign).
 Benign tumor : These are not
cancerous. They either cannot
spread or grow, or they do so
very slowly. If a doctor
removes them, they do not
generally return.
 Malignant: Malignant tumors
are cancerous. The cells can
grow and spread to other parts
of the body.

12. Normal Cell vs Cancer Cell – The Key
Differences
• Cell shape
cancer cells are
misshapen and
irregular in shape.
Normal cell of same
cell type will look
extremely similar,
maintaining a uniform
shape. But cancer cells
differ.

13. Normal Cell vs Cancer Cell – The Key
Differences
• Nucleus
In normal cells the
nucleus has a smooth
appearance and
maintains a uniform,
spheroid shape.
Cancer cell nuclei are
frequently misshapen
and bulges known as
“blebs” .

14. Normal Cell vs Cancer Cell – The Key
Differences
• Chromatin
The fine, evenly
distributed chromatin
found in normal cells.
coarse, chromatin are
found in cancer cells
aggregating into
irregular clumps that
vary in both size and
shape.

15. Normal Cell vs Cancer Cell – The Key
Differences
• Nucleolus
The nucleolus
becomes
increasingly
enlarged and
more irregular in
cancer cells –
cells can have
multiple nucleoli
within the
nucleus.

16. Normal Cell vs Cancer Cell – The Key
Differences
• Blood supply
 Angiogenesis is a vital process in normal cells that
occurs during development, growth, and wound
healing.
Tumors have the ability to secrete chemical signals
that stimulates angiogenesis

17. Normal cell Vs Cancer cells
Features Normal Cell Cancer Cell
Cell shape Uniform Irregular
Nucleus Spheroid shape, single
nucleus
Irregular shape, multi-
nucleation common
Chromatin Fine, evenly distributed Coarse, aggregated
Nucleolus Single, inconspicuous
nucleolus
Multiple, enlarged
nucleoli
Cytoplasm Large cytoplasmic
volume
Small cytoplasmic
volume
Growth Controlled Uncontrolled
Maturation Mature into specialized
cells
Remain immature and
undifferentiated
Blood supply Normal angiogenesis
(occurs during
development/ healing)
Tumor-induced
angiogenesis
Oxygen Usually aerobic Anerobic resp.

18. Normal cell Vs Cancer cells
Features Normal Cell Cancer Cell
Location Remain in their intended location Can spread to different
locations in the body
(metastasis)
Specialization
and maturity
Mature into distinct cell types with
specific functions; cell division stops
once they become fully
differentiated.
Do not specialize or
differentiate; divide quickly
before maturing and
remain immature and
undifferentiated.
Growth Factor
Proteins
Stop growing and dividing when they
stop producing growth factors
May produce their own
growth factors that
stimulate reproduction
Apoptosis
(programmed
cell death)
Occurs when a cell is no longer
needed, grows old or when DNA
damage cannot be repaired.
Do not repair themselves
and do not undergo
apoptosis, and thus live
longer.

19. References
1. Normal and Cancer Cells Structure: Image Details - NCI
Visuals Online. (2018). Retrieved from
https://visualsonline.cancer.gov/details.cfm?imageid=2512
2. Nandini, D.B. (2017) Cancer Cell Nucleus: An Insight. J
Mol Biomark Diagn S2:026. doi:10.4172/2155-9929.S2-
026
3. Papetti, M., & Herman, I. (2002). Mechanisms of normal
and tumor-derived angiogenesis. American Journal Of
Physiology-Cell Physiology, 282(5), C947-C970. doi:
10.1152/ajpcell.00389.2001
4. Eales, K., Hollinshead, K., & Tennant, D. (2016). Hypoxia
and metabolic adaptation of cancer cells. Oncogenesis,
5(1), e190-e190. doi: 10.1038/oncsis.2015.50
5. Cancer cells. (2018). Cancer Research UK. Retrieved from
https://www.cancerresearchuk.org/about-cancer/what-is-
cancer/how-cancer-starts/cancer-cells