Easy.
One hit theory is the hare (as in wabbit) brained idea that one molecule of a toxic substance is enough to cause cancer or the toxic effect.
It is the perfect rule for the fanatic nanny precautionary principle (no risk is tolerable) ambitious regulator set.
Since one hit originally was used for radiation it has been expanded by fiat of the science establishment without evidence.
One hit is espoused by the National Academy of Sciences and is nothing more than adopting the BEAR (biological effects of radiation committee) conclusions of the 50s.
I do real life tox–thresholds do exist. Pharmacology is about thresholds for effect, toxicology is about thresholds for harm. One hit is the toxicologist’s version of the silly homeopathic theory of pharmacology.
One hit, no threshold is “consensus” junk science but very helpful for aggressive regulators and ambitious researchers, who can follow the sensitivities of their monitors to zero, all the while claiming they are saving the world.
Wanna learn more, go to Ed Calabrese’s writings. He is a genuine heroic toxicologist who makes the EPA research and Linear modeling with no threshold what it is, a convenient policy hook that allows sensitive monitors to allow EPA to regulate the world from anything that once caused a rat or mouse to get sick at overwhelming doses.
Are you aware that the rat and mouse experiments use heroic exposures, at the level where the exposure kills half the subjects? Why sure you are, and that’s really good bench tox, isn’t it?
Make sense? Hope so.
Everything causes cancer, global warming, and species extinction. More studies are needed to find what else is caused by everything.
Read “The Apocalyptics” by Edith Efron.
This is the opening paragraph of a review:
“The Apocalyptics” has a complex title page. The main title is followed by
“Cancer and the Big Lie”, “by Edith Efron”, and “How Environmental Politics
Controls What We Know About Cancer”. That is a brief and fair summary of the book.
And one more paragraph:
What is a non-carcinogen? Again, no definition, but there is no such thing.
Everything is in one of two categories. It causes cancer or it has not yet
been evaluated fully. One sloppy study that indicates cancer is proof of
cancer, but ten careful and thorough studies of the same substance that find
no sign of cancer is proof of a need for more studies.
This was well worth the hour.
http://atomicinsights.com/calabrese-explains-hormetic-dose-response-model-to-cato-institute/
That the one-hit theory fails should be obvious from observation, in the range of intuitively obvious to the most casual observer.
Mutations are probably not the main cause of cancer, its failures in the genetic duplication/replication process.
That’s why aging increases cancer rates.
Multiploidy, polyploidy, not mutations, characterized cancer cell lines, which is why they are heavy with genetic material in the nucleus. Big nuclei overloaded with genetic material is a way to identify malignant cells.
Don’t disagree with your other points, just would warn that mutation is not the most important factor in developing malignant cell lines.
The oncologists i talk to splain it as a decline in the quality of the telomeres which are strands that control the replication mechanics that help to make duplication of chromosomes work. cancer cells end up with multiples of one, many, sometimes all of the chromosomes in the cell line that results.
Bad or short telomeres increases the rate of improper duplication, or whatever that are part of the replication and orderly splitting process.
I know, sounds like i stayed at a Holiday Inn Express. Having a bad memory helps.
It is an interesting estimate of one of the driving forces, but in real life, its effect is offset in opposite directions by unknown amounts. There is a near-perfect repair of DNA damage caused by the decay of its own atoms, thermal motion, high-energy particles and what not. Such adverse factors need to be really strong to overcome the capacity of repair mechanisms. On the other hand, there are non-genetic errors.
Apart from genetic mutations, cancer is also caused by normal development. Given what we know about how cells grow, divide, die, morph, travel, communicate, negotiate, compete and co-operate, our lives appear contingent on incredibly bizarre co-incidences. Development never stops until death, errors happen and get corrected (or not) all the time, and in most cases of “natural death” we can think of the organism as having achieved its ultimate maturity. In that state, you often find that one particular cell type has become dominant at the expense of other types, or you find important parts missing. Life is extremely haphazard. It can go wrong any moment between conception and death, in an infinite number of ways, even in the absence of mutations.
The human body contains about 10^13 cells, each with about 6 picograms (6×10^-12 g) of DNA.
That makes about 60 grams of DNA per person. About 40% of the weight of the DNA is carbon (about 24 grams) which Avogadro’s number tells us is 2 moles, or about 12×10^23 carbon atoms.
About 1 in 1 trillion (10^12) of those carbon atoms is radioactive carbon-14.
So we have about 1.2×10^12 atoms of radioactive carbon INSIDE OUR DNA.
Half of them (6×10^11) will decay in 5730 years (1.8*10^11 seconds).
That is an average of about 3.3 radioactive decays of carbon-14 in our DNA each second, EVERY ONE OF WHICH has a 100% certainty of causing a DNA mutation.
According to the ‘one hit’ theory, we should all have cancer within moments of our CONCEPTION, and are lucky to be born alive, albeit doomed.
Doc, +1 for the analogy with the silly homeopathic theory. By putting all silly stuff in the same bin, memory is freed.