What
is Cancer?
Cancer is a disease of cell where the cell grow
abnormally, continuously and relentlessly. The excess cell thus produce a
tumor which in time split off, some of
these cell spreading to other parts of the body or organ where they produce
secondary cancer and ultimately cause the vital organ dysfunction or damage and consequently cause death.
abnormally, continuously and relentlessly. The excess cell thus produce a
tumor which in time split off, some of
these cell spreading to other parts of the body or organ where they produce
secondary cancer and ultimately cause the vital organ dysfunction or damage and consequently cause death.
Carcinogenesis:
Carcinogenesis is a sequential process involving Initiation,
Promotion (Pre-malignancy), Progression (Malignancy and Metastasis) which are
primarily induced as a result of exposure to carcinogens.
Promotion (Pre-malignancy), Progression (Malignancy and Metastasis) which are
primarily induced as a result of exposure to carcinogens.
The major carcinogens that cause cancers are-
-Chemicals (soft
drinks, organic solvent, fast food)
drinks, organic solvent, fast food)
-Radiation (Sun bath,
X-ray)
X-ray)
-Viruses
Genetic
mechanism of cancer:
Chemical carcinogens such as those in tobacco, azo-dyes, aflatoxins, benzene
are clearly implicated to cancer induction in human and animals.
Certain herpes and papilloma group DNA and type C RNA viruses have also
been implicated as causative agent in animal as well as human cancers.
Oncogenic RNA viruses contain a ‘reverse transcriptase’ enzyme that
permits translation of the RNA message of tumor virus into the DNA code of the
infected cells.
A specific human T-cell leukemia virus (HTLV-1)
related to HIV-1 is the causative agent for this type of leukemia.
related to HIV-1 is the causative agent for this type of leukemia.
Development
of Cancer:
Cancers develop as a consequence of multiple changes
which activate oncogenes and inactivate tumor suppressor genes. Each human cell
contains tens of thousands of genes and a few proto-oncogenes that may be
responsible for cell proliferation. On exposure to carcinogenic influences, one
or more of the proto-oncogenes activate oncogenes. Cells carrying these
activated oncogenes become cancerous. Vital oncogenes are introduced into human
cells by virus to the development of cancers.
which activate oncogenes and inactivate tumor suppressor genes. Each human cell
contains tens of thousands of genes and a few proto-oncogenes that may be
responsible for cell proliferation. On exposure to carcinogenic influences, one
or more of the proto-oncogenes activate oncogenes. Cells carrying these
activated oncogenes become cancerous. Vital oncogenes are introduced into human
cells by virus to the development of cancers.
Absence or inactivation of anti-oncogenes or tumor suppressor genes can
also contribute to the development of cancer.
Anticancer
drug development:
1. During
the last 4 decades anticancer drug are developed by screening and
rational design of new compounds.
the last 4 decades anticancer drug are developed by screening and
rational design of new compounds.
2. By
synthesis of peptide and protein with recombinant DNA
techniques.
synthesis of peptide and protein with recombinant DNA
techniques.
3. Attempt
has been taken to produces monoclonal antibodies.
has been taken to produces monoclonal antibodies.
4. Target
of these anticancer drug is to remove all most all of the cancer cell from the
body .But none of the currently used anticancer agent is capable to remove all
of the cancer cell. That’s why, combination therapy is used to make success of
anticancer treatment. Even having so many attempt, none of these therapy is successful,
if the cancer is in metastatic state.
of these anticancer drug is to remove all most all of the cancer cell from the
body .But none of the currently used anticancer agent is capable to remove all
of the cancer cell. That’s why, combination therapy is used to make success of
anticancer treatment. Even having so many attempt, none of these therapy is successful,
if the cancer is in metastatic state.
Combination therapy are of 4 types. They are-
1. Surgery
2. Chemotherapy
3. Radiotherapy
4. Biotherapy
