APPLICATION OF COMPETITION THEORY TO TUMOR-GROWTH - IMPLICATIONS FOR TUMOR BIOLOGY AND TREATMENT

To assess critical parameters controlling tumour growth and response t o therapy, competition theory models the tumour-host interface as a ne twork of interacting normal and malignant cell populations using coupl ed, non-linear differential equations. When the equations are analysed under conditions which simulate tumour development, three phases of t umour growth, each with different critical parameters, can be predicte d. Transitions between these phases correspond to the initiation, prom otion and invasion stages demonstrated in experimental models of carci nogenesis. Critical cellular properties for each transition are predic ted including phenomena already demonstrated experimentally such as th e linkage of invasive tumour growth with acquisition of angiogenesis. The model also predicts the previously unknown phenomenon of ((functio nal equivalence)) in which disparate tumour traits can play identical roles in tumour growth and invasion. This approach allows the diverse but inconsistent properties of transformed cells to be understood acco rding to their specific contribution to tumorigenesis. The models have significant implications for treatment strategies. (C) 1996 Elsevier Science Ltd