Any one of a group of diseases that occur when
cells in the body become abnormal and have
the potential to spread and establish growth in nearby
tissues and other parts of the body
Carcinogenic (cancer) process:
At the beginning, a change in a
cell, tissue or
organ is necessary to initiate the
carcinogenic process. This change induced by
exposure to a carcinogen is called
'initiation'. Initiation is not necessarily sufficient to develop cancer.
A second step, called 'promotion' has to arise. Promotion itself is not
sufficient either and is the process whereby an initiated cell, tissue or organ
develops focal proliferation.
[UV radiation, for instance, is both an
initiator and a promoter of skin cancers, which means it is a complete
The carcinogenic process can be modulated positively or negatively. The
positive modulation speeds up the process, shortens the latency period between
initiation and cancer development, increases the intensity or changes the nature
of the cancer. The negative modulation slows the process down, prolongs the
latency, decreases the intensity and changes the nature of the cancer. This
negative modulation can be considered as cancer prevention. To prevent cancers
the factors capable of modifying the effect of initiation or promotion or acting
as modulators have to be known.