Final answer:
Option a.
The most often mutated oncogene in human tumors is TP53, encoding the p53 protein, which is vital for cell cycle control and apoptosis. These mutations are implicated in about 50% of all human cancers and are associated with a high risk of cancer in individuals with Li-Fraumeni syndrome.
Step-by-step explanation:
The oncogene that is most often mutated in human tumors is TP53, which encodes the p53 protein. P53 is classified as a tumor suppressor protein which plays a critical role in controlling cell division and apoptosis.
Mutations in the TP53 gene are found in about half of all human cancers across various types (pancreatic, lung, renal cell, breast, etc.).
These mutations can lead to unregulated cell proliferation and suppression of normal apoptotic processes.
Individuals with a condition known as Li-Fraumeni syndrome, who carry at least one mutated p53 allele, have a dramatically increased risk of developing cancer.
In cancer cells, a mutated p53 gene cannot properly fulfill its role as a guardian of the cell cycle, leading to the propagation of mutations and accumulation of additional genetic damage, contributing to tumorigenesis.
Therefore, please mention the correct option in your final answer: the correct option is (a) TP53, which encodes the p53 protein.