Initiation phase
→ The initiating agent or toxicant will interact with the normal cell → it will cause DNA damage or alteration of DNA structure (mutation) → then it will become initiated cells
→ There are instances/ processes that the body
can initiate repair on DNA level (excision repair, nucleotide repair, recombinational repair)
→ However if it is beyond repair → The initiated
cell cannot be fixed. We cannot reverse the
initiated cells
1 REMAIN static and non-dividing state
2 possess mutation that are incompatible with normal functions → As a defense of the body, it may initiate
apoptosis or kill the initiated cells itself
3 undergo cell division resulting to proliferation → It may enter or proceed to the promotion stage
1 Promotion phase
2 Tumor promoter
→ Reversible process in term of removal of
promoting agents or tumor promoter → that
results to focal cells or focal lesions returning to a
single initiated cells