  We introduce an in silico model for the initial spread of an aberrant
phenotype with Warburg-like overflow metabolism within a healthy homeostatic
tissue in contact with a nutrient reservoir (the blood), aimed at
characterizing the role of the microenvironment for aberrant growth. Accounting
for cellular metabolic activity, competition for nutrients, spatial diffusion
and their feedbacks on aberrant replication and death rates, we obtain a phase
portrait where distinct asymptotic whole-tissue states are found upon varying
the tissue-blood turnover rate and the level of blood-borne primary nutrient.
Over a broad range of parameters, the spreading dynamics is bistable as random
fluctuations can impact the final state of the tissue. Such a behaviour turns
out to be linked to the re-cycling of overflow products by non-aberrant cells.
Quantitative insight on the overall emerging picture is provided by a spatially
homogeneous version of the model.
