Final answer:
The statement is false as genetically engineered mice are used for in vivo experiments, not in vitro. GEM allows researchers to study the effects of TSG mutations and cancer development in a living organism.
Step-by-step explanation:
The statement that genetically engineered mice (GEM) allow for restructuring the tumor-promoting effects of heterozygous mutation of TSGs (tumor suppressor genes) and their LOH (loss of heterozygosity) "IN VITRO" is False. Genetically engineered mice are used for in vivo studies, not in vitro. These mice can be engineered to study the effects of specific genes on cancer progression, including the function of TSGs. Examples of this include engineering T-lymphocytes to express chimeric antigen receptors (CARS) to target cancer cells and observing the effects of gene mutations on tumor development in vivo.
It is crucial to differentiate between in vitro (test tube or culture dish) and in vivo (within a living organism) methods in genetic and cancer research. While GEM can be used to mimic human disease conditions in vivo, creating a similar environment in vitro does not involve the use of live animals.