CANCER STEM CELLS: Redefining the Paradigm of Cancer Treatment Strategies

Table 2.

Genetic Aberrations Involved in Cancers Originating from Stem Cells

Stem cell Activatior	Agent Involved	Tumor suppressor Gene Inactivation	Premalignancy	Oncogene Activated	Malignancy
For five of the most common cancers, an environmental agent causing stem cell activation is shown along with an agent contributing to tumor suppressor gene inactivation and/or oncogene activation (a few examples of which as shown). These events lead to the formation of a pre-malignant lesion that is at risk to progress to malignancy. The second, fourth, and fifth entries are incorporated from Figure 2.
Tobacco smoke →	Tobacco smoke	P53,RB1  →	Bronchial Dysplasia	→	Lung Cancer
Inflammation →	Mutagens	APC  →	Colon Polyps	→	Colon Cancer
Hepatitis B, C viruses →	Aflatoxin	?  →	?	MYC  →	Liver Cancer
Estrogens →	Mutagens	P53  →	Hyperplasia	→	Breast Cancer
UV →	UV	PTCH  →	Solar Keratosis	→	Basal Cell Carcinoma