Overview of the Cancer
“Structure
and Characteristics of Normal and Cancer Cells”
1.
Cancer
·
Tumors, which in the past has been used as a non-neoplastic term as used by
Celsus in describing the cardinal signs of Inflammation to mean swelling
but its use now is equated with Neoplasm
2.
Neoplasia
·
It derived from 2 Greek words
Neos = New
Plasia = Thing Formed
o
Hence, Neoplasia in simple terms means the
process of forming new things or simply, new growth.
“A neoplasm is an abnormal mass of tissue, it’s
growth exceeds and is uncoordinated with that of the normal tissue and persist
in the same excessive manner after cessation of the stimuli which evoke the
change.”
(Dr. RA Willis)
3.
Features
of Neoplasm
·
Excessive cellular proliferation
·
Autonomous growth - uncoordinated
·
Derived from cells with proliferative capacity
(active cell cycle)
·
Results from alterations in DNA
·
Some resemblance to cell of origin
Epidemiology of Cancer
4.
Introduction
Cancer is a group of more than 200 diseases characterized
by uncontrolled and unregulated growth of cells.
Cancer is often considered a disease of aging, with the majority of cases (77%) diagnosed in those over age 55 years, it occurs in people of all ages.
Cancer is often considered a disease of aging, with the majority of cases (77%) diagnosed in those over age 55 years, it occurs in people of all ages.
5.
The global
burden of cancer
6.
Global Cancer
Incidences 2018
7.
Global Cancer
Mortality 2018
8.
Percentages of
new cases
by type, region and sex
9.
Five Most
commonly diagnosed cancer
10.
Global Cancer
Incidences in Male 2018
11.
Global Cancer
Incidences in Female 2018
12.
The National
burden of cancer
·
Estimated number of people living with the
disease: around 2.25 million
·
Every year, new cancer patients registered: Over
11,57,294 lakh
·
Cancer-related deaths: 7,84,821
o
Men: 4,13,519
o
Women: 3,71,302
13.
The National
burden of cancer
·
Cancers of oral cavity and lungs account for over 25% of cancer deaths in
males and
·
Cancer of
breast and oral cavity account for 25% cancers in females.
·
The top five cancers in men and women account for
47.2% of all cancers;
·
these cancers can be prevented, screened for
and/or detected early and treated at an early stage.
14.
The National
burden of cancer
15.
The National
burden of cancer
·
One woman dies of cervical cancer every 8 minutes
in India.
·
For every 2 women newly diagnosed with breast
cancer, one woman dies of it in India.
·
Mortality due to tobacco use in India is
estimated at upwards of 3500 persons every day.
·
Tobacco (smoked and smokeless) use accounted for
3,17,928 deaths (approx) in men and women in 2018.
Biology of Cancer
“The adult human body contains over 100 trillion
cells.”
About three billion of those cells die—and most are
replaced—every minute.
16.
Cell
·
Cells are the simplest units of all living
matter.
o
Some exist as independent organisms. (such as
microscopic amoeba and bacteria)
o
Others function only when part of a larger
organism. (such as the cells of the human body)
·
These tiny forces of life do more than give the
body structure.
·
They also orchestrate all of the processes that
make life possible: respiration, movement, reproduction, digestion, and
excretion.
·
The body employs a vast array of cell types to
accomplish these varied tasks.
· In fact, the human body consists of about 200 different types of cells. These cells vary greatly in size and shape, both of which are dictated by the cell’s function.
17.
The Basic
Structures of the Cell
18.
Cell Growth
and Reproduction
19.
Biology of
Cancer
·
The body normally functions within an orderly
system of cell division and cell death.
·
When cells multiply faster than they die,
abnormal growths (tumors) result.
·
Two major dysfunctions in the process of cancer
development are
o
Defective cell proliferation (growth) and
o
Defective cell differentiation
20.Defective cell proliferation (growth)
·
The normal body’s cells proliferation (growth)
are controlled by-
o
An intracellular mechanism that determines the necessity of cell proliferation
§
Under normal conditions, a state of dynamic
equilibrium
·
i.e., cell proliferation equals cell degeneration
or death.
·
So, process of cell division and proliferation is
activated only in the presence of cell degeneration or death.
§
Under physiologic need, Cell proliferation also
occurs.
·
For example, a normal increase in WBC count in
case of infection.
o
Contact Inhibition
§
Normal cells respect the boundaries and territory
of the cells surrounding them.
§ inhibit cell growth through the physical contact of the surrounding cell membranes.
21.
Defective cell
proliferation (growth)
·
The cancer cells Defective proliferation (growth)
-
·
Pyramid effect
o
In most situations, cancer cells multiply at the
same rate as the normal cells from which they originate but respond differently
to intracellular signals regulating equilibrium
o
Proliferation is indiscriminate and continuous.
o
Each cell division creates two or more offspring
cells.
o
Because of this there is continuous growth of a
tumour mass
·
Loss of contact inhibition
o No regard for cell boundaries and Grow on top of one another and on top of or between normal cells
22.
Defective cell
differentiation
·
Cell differentiation
o
all body cells are derived from the fertilized
ova,
§
all cells have the potential to perform all body
functions.
§
As cells differentiate, this potential is
repressed, and the mature cell is capable of performing only specific
functions.
o
there is a stable and orderly phasing out of cell
potential.
o
Under normal conditions the differentiated cell
is stable and will not dedifferentiate.
o
Two types of normal genes that control the
differentiation and proliferation, those are protooncogenes and tumor
suppressor genes.
23.
Defective cell
differentiation
·
Protooncogenes
o
Normal cellular genes that are important
regulators on normal cellular processes, that promote growth.
o
Mutations that alter their expression, can
activate them to act as oncogenes (tumor-inducing genes)
o
It works as the genetic lock that keeps the cell
in its mature functioning state.
o
When this lock is “unlocked,” due to exposure to
carcinogens and mutations occur. The abilities and properties that the cell had
in fetal development are again expressed and cell regains a fetal appearance
and function.
24.Defective cell differentiation
·
Tumor suppressor genes
o
Regulate cell growth by ‘growth
Suppression’.
§
i.e. prevent cells from going through the cell
cycle.
o
Mutations render them inactive
o
Examples of mutation in tumor suppressor genes
that increase the risk of cancer -
§
BRCA1 and BRCA2 - breast and ovarian cancer.
§
APC gene - colorectal cancer.
§
p53 - bladder, breast, colorectal, esophageal,
liver, lung, and ovarian cancers.
Cancer Cells and Normal Cell
Characteristics
25.
Development of
Cancer
·
Chemical, environmental, genetic, immunologic,
viral, or spontaneous in origin
·
Initiation
o
Mutation of genetic structure
o Has potential to develop into clone of neoplastic cells
26.Development of Cancer
·
Promotion
o
Characterized by the reversible proliferation of altered cells
o
Activities of promotion (e.g. obesity, smoking, alcohol) are reversible
o
Latent period
o Initial genetic alteration to clinical evidence of cancer
27.
Development of
Cancer
·
Progression
o
Characterized by increased growth rate of tumor as well as its
invasiveness and metastasis
o
Metastasis = spread of cancer from primary (initial) site to distant
site
§ Metastasis process begins with rapid growth of
primary tumor
§ Tumor angiogenesis - formation of blood
vessels within the tumor; critical for tumor survival
28.Development of Cancer
The pathogenesis of cancer metastasis.
Great Blog!Thank you for sharing and explaining.
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