To Aisha Sivakumar:

I think that Arun Biur's reply misses the point. The causes of cancer are accumulated mutations in genes that either promote oncogenesis (these genes are necessary in embryonic development but are shut down in the adult) or that suppress tumorigenesis (thus turning tumorigenesis on). This may be by point mutations, deletions, or translocations (often putting a normally supressed gene downstream of a promotor that inappropriately turns it on. One train of thought argues that it is only important when this happens in adult stem cells which are already immortal (express telomerase constitutively) as the other cells do not live long enough to still be around for the duration of the latent periods for most human cancers (10-20 years for solid tumors) -- see LG Lajtha's chapter "Stem cell concepts" in "Stem Cells, their Identification and Characterization" edited by CS Potten and published by Churchill Livingstone in 1983. This can be done by chemical mutagens and/or by ionizing radiations. For the role of ionizing radiations, I would recommend that you start looking at review articles in Radiation Research, International J Radiation Bioloogy, for articles about the Japanese atomic bomb survivors and the followup of their cancer incidences. Also articles about the Chernoble exposed population cancer incidences. David Brenner (Columbia University) is a good starting point. Then follow the papers to which he refers.

For the role of chemically induced mutations, Mutagenesis is another journal that has articles about cancer induction. There are many others, but the literature is so large that these may be good starting points.

During 1945, when Hiroshima and Nagasaki suffered ATOMIC ATTACK, temperature rose to about 3000 0 C .I was under the impression that every body who had to die, were cremated alive without any mercy. But later on also people kept on dying due to various implications including CANCER. A lot of research had been done to save them to give them few months of life. All elements of atomic number 80 and above are radio-active and created environment for creation of cancer causing genetic change in humans due to exposure to neutrons, neutrino and bombardment of protons.A researcher could safely work only under a shield of LEAD or behind 7 feet of pure concrete in order to save themselves from such atomic radiations. During recent earthquake in JAPAN as a damage,Tokyo Water Bureau officials say levels of radioactive iodine 131 in some city tap water is two times the recommended limit for infants.

The officials told reporters on Wednesday 27 March 2011 from a water treatment center in downtown Tokyo that supplies much of the city's tap water has been found to be that some water contained 210 becquerels per liter.

They said the limit for consumption of iodine 131 for infants is 100 becquerels per liter. They recommended that babies not be given tap water, although they said the water is not an immediate health risk for adults.

In order to understand the exposer due to isotopes, few years back,a crude experiment was carried out in which mice were given water which had various percentages of heavy water, which is water in which both hydrogen atoms were replaced by deuterium. Low percentages of heavy water didn’t have noticeable effects, but more than 20% heavy water did have adverse health effects and mice given 80% heavy water died within days. In another experiment, bean plants grown from seed given increasing fractions of heavy water showed stunted growth compared with control plants given normal water.

The reason for these adverse effects is that replacing hydrogen with its heavier isotope deuterium slows down the rate of any chemical reaction in which the chemical bond to the hydrogen atom is broken. This includes a great many chemical reactions occurring in biological systems, and not just those involving water; the hydrogen atoms from water end up in a number of other biomolecules, so any process involving these hydrogen atoms will also be slowed down. Thus the heavy water acts like a brake on a large number of metabolic processes.

The amount by which an isotopic substitution like this slows down a chemical reaction is called a kinetic isotope effect. Such effects are a major tool in the study of chemical reactions, including enzymatic reactions. Deuterium isotope effects can be as large as 6 or 7 times, which means that the reaction rate is 6 or 7 times slower when deuterium is substituted for hydrogen. In rare cases where a quantum mechanical effect called tunneling occurs in the reaction, deuterium isotope effects of 20 or more have been observed. The major reason for the difference in the rates of the chemical reactions involving the two isotopes of hydrogen is the difference in their masses. Deuterium atoms have an atomic mass of 2, which is double that of normal hydrogen. Of course other atoms have isotopes also, and your comment that for isotopes of other elements these effects would not be present is perceptive but not quite completely correct. Isotope effects do occur with the heavier elements but they have much smaller effects. For instance if we replaced the oxygen of water (which is normally oxygen 16) with oxygen 18 we end up with a water molecule having the same mass as in the heavy water discussed above, but in which the isotope effects on its reactions would be very small. This is because changing the oxygen atom’s mass from 16 to 18 is a much smaller fractional change than the doubling of mass of hydrogen when we go from hydrogen to deuterium. Oxygen-18 isotope effects are never more than about 1.07, or 7 % slower with the heavier. In a solid CYSTALLINE ISOTOPE STRUCTURE, CRAZING AND CRACKS would occur which would cause result from differences in atomic masses with a sufficient alteration in partition functions. For a chemical system at equilibrium statistical thermodynamics is considered. This is the procedure by which microscopic properties of individual molecules in vibrational modes, molecular configurations and atomic masses, can be converted to macroscopic properties of the system ,i.e. free energy, entropy etc. and thus the role of isotopes of higher elements ,can be evaluated which would have effect on metabolic activity less than that of deuterium atoms in water.

To Aisha Sivakumar:

I think that Arun Biur's reply misses the point. The causes of cancer are accumulated mutations in genes that either promote oncogenesis (these genes are necessary in embryonic development but are shut down in the adult) or that suppress tumorigenesis (thus turning tumorigenesis on). This may be by point mutations, deletions, or translocations (often putting a normally supressed gene downstream of a promotor that inappropriately turns it on. One train of thought argues that it is only important when this happens in adult stem cells which are already immortal (express telomerase constitutively) as the other cells do not live long enough to still be around for the duration of the latent periods for most human cancers (10-20 years for solid tumors) -- see LG Lajtha's chapter "Stem cell concepts" in "Stem Cells, their Identification and Characterization" edited by CS Potten and published by Churchill Livingstone in 1983. This can be done by chemical mutagens and/or by ionizing radiations. For the role of ionizing radiations, I would recommend that you start looking at review articles in Radiation Research, International J Radiation Bioloogy, for articles about the Japanese atomic bomb survivors and the followup of their cancer incidences. Also articles about the Chernoble exposed population cancer incidences. David Brenner (Columbia University) is a good starting point. Then follow the papers to which he refers.

For the role of chemically induced mutations, Mutagenesis is another journal that has articles about cancer induction. There are many others, but the literature is so large that these may be good starting points.

Dear Coleagues,

I transfer you the response I maid to a young researcher who asks me rather similar questions.

I hope it will help you.

Best regards

Didier J

"I have well notice your request.

So, I'll go to give you some advices and I hope it will help you:

- for your future carrier, if you want to continue your formation by a PhD in foreign countries, you have to connect you to different web site as Naturejobs or jobs published in Lancet reviews. You have offers for Phd progams and after post-doc programs and according to the subject (cancer) or localisation (France or over country) you can select it by keywords in field "location" or "subject",

- I give you some reference books also:

*Encyclopedia of Cancer

Schwab, Manfred (Ed.) - 2nd Edition., 2009, LXXXVII, 3235 p. 979 illus. Springer.- print (book), Hardcover, ISBN 978-3-540-36847-2 (inconvenient: expensive; to be bought by your institution)

*The Genetic Basis of Human Cancer, Bert Vogelstein, Kenneth Kinzler 2ème edition-ISBN-13: 9780071370509, MacGraw Hill Pages: 821 (the best book in genetic of cancer, to my mind)

- to have discoveries in real time, you have to connect you to cancer reviews (cancer, cancer research ...) through medline website, and you can have free of charges the abstract (search by keywords). Best articles for you are the review articles that synthetises researches in a particular field.

- finally, in France, the website of national research institutions (CNRS, INSERM) have a particular page for international relations to announce the different international possibilities in real time (see link to website here: https://dri-dae.cnrs-dir.fr)"

sir,metabolic activity varies differently.however ,I appreciate your reply and I will read this aspect also.What I have said that microscopic and macroscoptc aspects get related through thermodynamics.

@ Dr. Jambou: The Genetic Basis of Human Cancer by B. Vogelstein is indeed the best and down to earth book on cancer which can teach cancer to a researcher, a medicine person and to a considerable extent to a layman as well.

Hey....thank you all for the help...and Christopher, I shall look up your references....Dr. Jambou, thanks for the books....The one that you mentioned in particular...The Genetic Basis of Human Cancer, I am thinking of buying it. I am sure it is going to be of great help.

I agree with Abhishek.. Vogelstein's book or even papers are best to understand the basic of cancer biology...