2. INTRODUCTION TO CANCER
We can define cancer as the uncontrollable growth of cells.
In normal cells, there are some factor that inhibits the over
growth.
but in cancer cells, the activity of these factor is suppressed.
We can also define cancer as a disease that involves changes
or mutations the genome.
These mutations produce protein that disrupt the delicate
cellular balance between cell division and quiescence,
resulting in cells that keep dividing to form cancers.
3. Types of cancer:
The cancer can be divided in the following types.
Breast cancer
this type of cancer affects the cells of the breasts. Males are
less likely to have breast cancer in comparison to females. Less
than 1% of the breast cancer develops in males.
Prostate cancer
the prostate cancer is the cancer of prostate gland of male.
This disease rarely occurs before the age of 40. The screening
is done by two test (commonly) DRE and PSA blood test.
4. Skin cancer
the cancer of the skin may be of two types
1. Basal cell cancer
2. Melanoma
5. Lung cancer
It is the cancer of the lungs.
We can divide it as :
1. Small cell lung cancer
2. Non small cell lung cancer
Leukemia
The blood cancer is termed
as leukemia.
In it the no. of WBCs increase
in the blood.
6. Pathophysiology of cancer:
• Immortality
• Production of growth signaling molecule
• Inhibition of the growth inhibitors
• Resistance to the apoptosis
• Angiogenesis
• Metastasis
The steps of
development
of cancer are
as follows :
7. Immortality
It means continuous cell division and limitless replication.
The chromosome of every cell is surrounded by the telomeric DNA,
which is involved in the cell growth.
With the every cell division the telomeric DNA decreases size and as it
finishes completely the cell stops dividing.
8. Production of the growth signaling molecule
The proto-oncogenes present in the cell, secrets protein which is
involved in the regulation of cell division.
Due to mutation these genes get converted in to the oncogenes. The
protein secreted by the oncogenes is highly overactive and causes the
cancer.
9. Inhibition of the growth inhibitors
The nearby cells send signals to stop cell division.
Cancer cells override the signals by secreting
inhibitors and divide continuously.
Resistance to apoptosis
The programmed cell death is inhibited by
these cancer cells.
10. Angiogenesis
The tumor cells secrets angiogenic factors by which they forms the
network of blood vessels.
It allows the entry of tumor cells in the blood circulation.
11. Metastasis
The migration of the tumor cell form the one tissue to the other
tissues of the body by the blood stream is termed as the metastasis.
