A 32-year-old woman visits the office to have a breast lump evaluated. She noticed the lump a few months ago and believes it is growing larger. The patient had a right lower limb amputation at the age of 17 due to osteosarcoma. Her mother died from an adrenal tumor, and her younger sister from leukemia. A 5-cm firm immobile mass with irregular borders is found in the left breast. Which of the following gene mutations is the most likely etiology for this patient's condition?

Question

Quizplus · Accepted Answer

Eductional Objective: Li-Fraumeni syndrome is indicated by a history of sarcoma, leukemia, adrenal, or breast cancer. Brain cancer is also fairly common. The syndrome is caused by an autosomal dominant mutation in the gene TP53, which codes for the tumor suppressor protein p53. Patients with this disorder are predisposed genetically to developing cancer at a young age. Patients with Li-Fraumeni syndrome inherit one mutated allele of TP53, but tumor development requires somatic mutation of the second allele (2-hit hypothesis).
p53 is critical for maintaining the integrity of the human genome by arresting cells with mutant DNA in the G1/S stage of the cell cycle until the damage is repaired.

A 32-Year-Old Woman Visits the Office to Have a Breast