32989_Lecture-2 The Molecular Basis Of Cancer Part-1.ppt

The Molecular Basis Of Cancer

1. Molecular Basis Of
Cancer

Non-lethal genetic damage lies at the
heart of carcinogenesis

Genetic hypothesis of cancer implies
that a tumor mass result from the
clonal expansion of a single
progenitor cell that incurred the
genetic damage

2. Types of Normal Cellular
Genes
3 Normal regulatory genes;
- Growth promoting protooncogene
-Growth inhibiting tumor suppressor
gene
-Gene regulate apoptosis
4
th
-- DNA repair gene

3. Normal cell growth

Any external stimuli leads to stimulation of
growth by growth stimulating gene called
Proto-oncogene

This should be stopped by gene which will
control the growth called
Tumor suppressor gene

Any mutated gene will be either repaired
by DNA repair gene or killed by gene
called apoptosis gene

5. Principles of
Carcinogenesis

Neoplastic transformation is a
progressive process involving
multiple “hits” or genetic changes.

Alterations in DNA cause changes in one
or more of the following types of genes:

Proto- oncogenes

Tumor suppressor genes

Genes regulate apoptosis

DNA repair genes

7. Tumor Development and
Growth

Transformation

Growth of transformed cells

Invasion of tumor cells into the
surrounding tissues

Metastasis of tumor cells to distant sites

8. Hallmarks of Cancer
1.Self sufficiency in growth factors
2.Insensitivity to growth-inhibitory signals
3.Evasion of apoptosis
4.Limitless replicative potential
5.Sustained angiogenesis
6.Ability to invade and metastasize
Six fundamental changes of cell PhysiologySix fundamental changes of cell Physiology

11. 30% OF ALL TUMORS