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"And the stars are projectors, yeah, projecting our lives down to this planet Earth." - Modest Mouse


5.28.2004

Advances In Tumor Research 

From The American Institute of Physics Bulletin of Physics News,
Number 686 May 28, 2004 by Phillip F. Schewe and Ben Stein:
TO STOP TUMORS, KNOW HOW THEY GROW. Stimulating the immune system in a certain way can cause immune-system cells to surround tumors and stop them from growing, researchers have found (Antonio Brú Espino, Environmental Sciences Research Center, Spanish Research Council, antonio.bru@ccma.csic.es,). Demonstrated in mice, the finding is a direct result of applying a new universal model of tumor growth developed over the last ten years in a collaboration between scientists at the Spanish Research Council and medical research centers in Spain.

The researchers have evidence to show that all tumors grow in the same way, irrespective of the tissue or species in which they develop (Brú et al., Biophysical Journal, November 2003). In a previous paper, these researchers reported that tumor growth, rather than being exponential as commonly believed, is a much slower "linear" process similar to the growth of certain crystals and other natural phenomena (Brú et al., Phys. Rev. Lett, 2 November 1998). Tumor cells, they have found, grow through the diffusion or migration of cancer cells at the tumor's outer edges. Only the cells close to the edge of the tumor proliferate--those inside the tumor do not, contrary to previous assumptions. According to the researchers' observations, cells formed at the edge of the tumor diffuse at the border of the tumor mass until they settle in curved depressions where the competition for space is lowest and where they are best protected from the immune system. In their new paper, Brú and co-workers show that the mechanical pressure exerted by immune-system cells known as "neutrophils" around mouse tumors can prevent the diffusion of these cells and thus prevent tumor growth. In 16 mice with a tumor mass in the muscle, the researchers induced neutrophil production by administering an immune system booster known as GM-CSF over two months. In a short time, they observed that GM-CSF altered the growth dynamics of the cells. The tumors of two mice regressed completely and 80-90% tumor-cell death was seen in the rest.

If the growth dynamics of tumors are universal, there is every reason to be hopeful the same result could be obtained in humans. Knowing how tumors grow, by cell diffusion at the surface, opens up the possibility of developing new and far more efficient ways of preventing their enlargement and spread. (Bru et al., Physical Review Letters, upcoming)



Comments:
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http://www.news-medical.net/?id=34242

Genetic evolution of tumours according to their growth dynamics.

Published: Friday, 11-Jan-2008

Medical Studies/Trials
A study co-directed by the Universidad Complutense de Madrid and La Paz hospital in Madrid identifies a protein of high expression in cells located at the tumour boundary that could play an essential role in the evolution of tumours and their invasive potential.
It is well accepted that tumour growth is a very complex process with many intervening factors, and in spite of being the subject of most investigations on a global scale; there are still many aspects that remain unknown, one of the most interesting of which is the relation between the dynamics of solid tumour growth and their gene expression.
The universal dynamics of tumour growth (Br?Albertos S, Luis Subiza J, Garc?Asenjo JL, Br?Biophys J. 2003) established that the growth dynamics of all tumours is similar. Such growth dynamics implied that the growth rate of the tumour follows a lineal function and that most of its activity takes place at the outer tumour boundary. This establishes a huge difference in the number of cell divisions that a cell located at the tumour boundary undergoes from the original tumour cell, when compared to the traditional model based on the Gompertzian growth pattern. Considering a tumour 2 cm3 in volume, following the previous model, a cell at the boundary of the tumour will divide 32 times from the original tumour seed, and using the new growth dynamics for solid tumour, the number of boundary cell divisions is estimated at 800 times from the original tumour seed........
 
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