Table 1.

Important features of old and new cancer model [19].

Old cancer model	New cancer model
(i) All tumor cells are equally tumourigenic (ii) Unregulated growth is due to the accumulation of multiple mutations that promote cell proliferation with concomitant silencing of growth inhibitory genes and blunting of cell death (iii) Cancer is a proliferative disease	(i) Only a minority of cells can form new tumors (ii) Unregulated cell growth is due to a disruption in the regulatory mechanism in stem cell renewal