Copyright © 1996, 1997, 2001 by Galen Daryl Knight and VitaleTherapeutics,
Possible Explanations for Tolerance
Large, rapidly-growing tumors are thought
to outstrip the blood supply and result in the death of tissues from a
lack of oxygen and other nutrients. Large numbers of tumor cells dying
and breaking away from a growing primary mass might be mistaken by the
immune system distal to the primary tumor as a signal that the existing
responses are sufficient to eliminate the tumor, resulting in a premature
attenuation of the immune response. This is particularly problematic when
any viable tumor cells being released are strongly adherent.
Accurate gauging of the needed response also is dependent upon the relative
numbers of released cells that are metastatic. When the vast majority of
cells succumbing to anoxia are normal, an additional erroneous signal might
be sent, i.e., that too violent of an immune response is already underway,
resulting in further attenuation of the immune response.