Answer:
As APC is indicated as a tumor suppressor, lack of APC would lead to tumor development in the mutated mice.
Step-by-step explanation:
The wnt signaling pathway plays an important role in controlling stem cell proliferation. Stem cells are present in the gut and other locations where they are required to be replenished after short intervals. In the gut, the gut epithelial is exposed to a very tough environment i.e. digestive acids. Thus it is replenished where the new stem cells originate from underlying stem cells.
Axin binding is the major component of this process. However, the unaffected axin leads to binding with a component termed TCF. TCF4 genes include cell cycle factors (such as myc) that encourage cell regeneration.
When the ligand is absent and APC is present, the axin bound with APC to form a team that directs and controls the cell regeneration.
Thus, if APC is not expressed in a cell, beta-catenin in the axin is available to bind to TCF inducing wnt response element genes that stimulate cell proliferation.
The result in tissue level is an enhanced rate of cell growth which leads to tumor.