Hybrid cancer cells have been recently discovered. They have greater ability to form metastasis. Here a simple mathematical
model is given for this phenomenon. Some comments about the possibility of their reaching brain are given.
Metastasis comprises a sequence of linked steps leading to the
dissemination of cancer cells from a primary tumor to other distant
tissues the overwhelming majority of cancer-related deaths still
result from the progressive growth of metastasis that are resistant
to conventional therapies [1,2].
Motivated by this the following model is presented for the
metastasis of hybrid cancer cells:
Let T1, H1 be the ordinary and hybrid tumor cells respectively
of the first tumor. Let N=T1+H1. The second tumor is assumed
to contain ordinary tumor cells T2. Hence the model can be
represented by
where a1,b1,b2,c2 are positive constants. The metastasis term
is c2H1.
The reason for the power 2/3 is that ordinary tumor cells grow
due to surface cells [3,4].
The equilibrium solution for the coexistence of both tumors is:
H1eq=T1eq/(a1-c2-1)
T1eq= [b1(a1-1-c2)/(a1-c2)]^3 (2)
T2eq=c2H1/(1-b2)
It is locally asymptotically stable if:
b2<1,
[1-(2/3)(a1-c2)/(a1-c2-1)][1+c2-a1]-1>0 (3)
[1-(2/3)(a1-c2)/(a1-c2-1)]+[1+c2-a1]>0
Since hybrid cells have a greater ability to invade other cells, it
is expected that they will invade brain cells. Hence brain tumors can
be a good source for identifying them. Moreover trying to attract
them to less important sites can be a feasible strategy to deal with
them. It may be difficult to test this idea experimentally, because the
hybrid state, in general, is unstable [5].