Final answer:
Defective DNA repair mechanisms in cancer lead to an accumulation of mutations, which may result in unregulated cell proliferation or tumors. These mutations can affect key cellular proteins, disrupting normal cell cycle control and preventing apoptosis, thereby contributing to cancer progression. Option C is correct.
Step-by-step explanation:
The consequence of defective DNA repair mechanisms in cancer is Accumulation of mutations. Defective or impaired DNA repair processes lead to the persistence of DNA damage, which over time can result in a buildup of mutations.
These mutations can alter the function of critical proteins, including tumor suppressor genes and those involved in the cell cycle control, leading to unregulated cell division and the potential formation of malignant tumors. Furthermore, defective DNA repair mechanisms can also interfere with the function of the p53 protein, which is responsible for detecting DNA damage and initiating repairs or signaling for apoptosis if the damage is beyond repair.
When this system fails, it can result in the survival and proliferation of cells with genomic errors, contributing to the progression of cancer.