Final answer:
If a cell with damaged DNA loses function of both TP53 alleles, it can lead to uncontrolled cell division and cancer, as p53 is crucial for DNA repair and apoptosis.
Step-by-step explanation:
When a cell possesses damaged DNA and both of its TP53 alleles are inactivated, it can lead to serious consequences including cancer. The p53 protein, which is encoded by the TP53 gene, has several vital functions that prevent the propagation of genetic errors and maintain genomic stability. These functions include halting the cell cycle to allow time for DNA repair, activating other genes that are necessary for the repair process, and initiating programmed cell death, or apoptosis, when DNA damage cannot be repaired. Without functional p53, a damaged cell may fail to detect errors or signal for repair, and as a result, continue dividing with genetic defects. This malfunctioning p53 can contribute to tumor development as it allows cells with mutations to replicate, accumulating more errors and transforming into cancer cells.