Came across some information from Bruce Ames, regarding mutagenesis,
carcinogenesis and the degenerative diseases of aging...

Cooking food is plausible as a contributor to cancer. A wide variety of
chemicals are formed during cooking. Four groups of chemicals that cause
tumors in rodents have attracted attention because of mutagenicity,
potency, and concentration. a) Nitrosamines are formed from nitrogen
oxides present in gas flames or from
other burning. Surprisingly little work has been done on the levels of
nitrosamines in fish or meat cooked in gas ovens or barbecued,
considering their mutagenic and carcinogenic potency. b) Heterocyclic
amines are
formed from heating amino acids or proteins. c) Polycyclic hydrocarbons
are formed from charring meat. d) Furfural and similar furans are formed
from heating sugars. Heating fat generates mutagenic epoxides,
hydroperoxides, and unsaturated aldehydes, and may also be of
importance. Epidemiological studies on cooking are difficult and so far
are inadequate to resolve a carcinogenic effect in humans.

Humans also ingest large numbers of natural chemicals from cooking food.
For example, more than a thousand chemicals have been identified in
roasted coffee; more than half of those tested (19/26) are rodent
carcinogens. There are more natural carcinogens by weight in a single
cup of coffee than potentially carcinogenic synthetic pesticide residues
in the average U. S. diet in a year, and there are still a thousand
known chemicals in roasted coffee that have not been tested. This does
not necessarily mean that coffee is dangerous, but that animal cancer
tests and worst-case risk assessments build in enormous safety factors
and should not be considered true risks.

References:
International Agency for Research on Cancer (1993) Some naturally
occurring substances: Food items and
constituents, heterocyclic aromatic amines and mycotoxins (International
Agency for Research on Cancer, Lyon, France).

Gold, L. S., Slone, T. H., Stern, B. R., Manley, N. B. & Ames, B. N.
(1992) Science 258, 261-265.

Gold, L. S., Slone, T. H., Manley, N. B. & Ames, B. N. (1994) Cancer
Lett. 83, 21-29.