Friday, October 27, 2006
brief introduction to cancer research using game theory
I gave yesterday a small and informal presentation on the research done in cancer using game theory. For whoever might be interested, the results are here.
Wednesday, October 25, 2006
Interview with mathematical biologist Luigi Preziosi
I guess it will be irrelevant for those of you that don't speak Spanish but the Spanish news paper El Pais has interviewed the mathematical biologist Luigi Preziosi. Luigi happens to be one of the coordinators of the EU Marie Curie Network in which I am involved.
In the interview he argues that biology is geting more mathematical, explains how mathematicians and life scientists and physicians collaborate, how the mathematical models can help to explain medical phenomena and hint to innovative therapies. He also says that traditional biologists are still necessary (as if that was not obvious: theoretical physicists still need experimentalist to work with so they can validate their theories, it should not be different in the life sciences, there would not be biology without people that know how to perform experiments).
In the interview he argues that biology is geting more mathematical, explains how mathematicians and life scientists and physicians collaborate, how the mathematical models can help to explain medical phenomena and hint to innovative therapies. He also says that traditional biologists are still necessary (as if that was not obvious: theoretical physicists still need experimentalist to work with so they can validate their theories, it should not be different in the life sciences, there would not be biology without people that know how to perform experiments).
Tuesday, October 24, 2006
Bach et al: An evolutionary-game model of tumour-cell interactions
L.A. Bach, S.M. Bentzen, J. Alsner and F.B. Christiansen. An evolutionary-game model of tumour-cell interactions: possible relevance to gene therapy. European Journal of Cancer 27 (2001) 2116-2120.
Bach et al have taken the work from Tomlinson and Bodmer (which I reviewed a few day ago) in which angiogenesis is studied with the help a Game Theory. In the previous case the game involved two players who could chose to produce angiogenic factors or to do nothing. As long as one of the players is willing to shoulder on the cost of producing the factor, both players get the benefit. As expected the result is a polymorphism in which both types of strategies coexist. I said that this polymorphism is to be expected since if there were only factor producing cells then non cooperating cells will have an advantage (since they get the benefits without paying the costs) whereas if the population is made of non cooperating cells then factor producing cells will have an advantage (as long as the benefit of producing the factor is higher than the cost).
The revision of the model proposed by Bach et al considers the implications of extending the game to three players if the benefits of angiogenesis appear only if two out of the three players cooperate to produce the factor.
The payoff table would look like this:
A+,A+ A+,A- A-, A-
A+ 1-i+j 1-i+j 1-i
A- 1+j 1+j 1
where A+ means factor producing and A- means that is not factor producing. Also i is the cost of producing the factor and j is the benefit.
Bach et al analyse how these cost and benefit parameters affect the equilibria and the existence of polymorphism. For this they use computer simulations and find that when the benefit is three times the cost something interesting happens. In that case the final composition of the tumour population would be a consequence of the composition of the original population. Most likely this finding has limited (if any) consequences in potential therapies since physicians have not got the ability to change the initial composition of phenotypes in a tumour. Still, the (qualitative) results can be used as a guide for gene therapies.
Bach et al have taken the work from Tomlinson and Bodmer (which I reviewed a few day ago) in which angiogenesis is studied with the help a Game Theory. In the previous case the game involved two players who could chose to produce angiogenic factors or to do nothing. As long as one of the players is willing to shoulder on the cost of producing the factor, both players get the benefit. As expected the result is a polymorphism in which both types of strategies coexist. I said that this polymorphism is to be expected since if there were only factor producing cells then non cooperating cells will have an advantage (since they get the benefits without paying the costs) whereas if the population is made of non cooperating cells then factor producing cells will have an advantage (as long as the benefit of producing the factor is higher than the cost).
The revision of the model proposed by Bach et al considers the implications of extending the game to three players if the benefits of angiogenesis appear only if two out of the three players cooperate to produce the factor.
The payoff table would look like this:
A+,A+ A+,A- A-, A-
A+ 1-i+j 1-i+j 1-i
A- 1+j 1+j 1
where A+ means factor producing and A- means that is not factor producing. Also i is the cost of producing the factor and j is the benefit.
Bach et al analyse how these cost and benefit parameters affect the equilibria and the existence of polymorphism. For this they use computer simulations and find that when the benefit is three times the cost something interesting happens. In that case the final composition of the tumour population would be a consequence of the composition of the original population. Most likely this finding has limited (if any) consequences in potential therapies since physicians have not got the ability to change the initial composition of phenotypes in a tumour. Still, the (qualitative) results can be used as a guide for gene therapies.
Tumour supressor gene involved in virus protection
Got this from mainstream media but the paper itself has been published in the EMBO journal in September. Researchers at the Madrid based Centre for Oncological Research have found a gene (for those interested in the gene itself: ARF) that is implicated in both tumour supression and protection from viral infection.
I guess this amounts to another cellular mechanism that has been successfully evolved to adopt an extra new function. The results of evolution can be messy but I'm still impressed.
I guess this amounts to another cellular mechanism that has been successfully evolved to adopt an extra new function. The results of evolution can be messy but I'm still impressed.
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