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TP53 Sequencing and Deletion/Duplication

Test code(s) 92560

Question 1. What is the clinical application of this test?

This test is used to assess the risk of certain cancers and guide follow-up. It detects point mutations, deletions, and duplications in the TP53 gene that are associated with Li Fraumeni syndrome. Li Fraumeni syndrome includes an increased risk for breast, bone, and other cancers, as well as early-onset cancers, including those diagnosed during childhood.

Question 2. Who may be appropriate for TP53 mutation testing?

The following individuals may be appropriate for this test:

  • Individuals with a personal history of breast cancer diagnosed before the age of 31
  • Individuals with a personal history of adrenocortical carcinoma, choroid plexus carcinoma, or rhabdomyosarcoma of embryonal anaplastic subtype
  • Individuals with a personal history of a tumor associated with Li Fraumeni syndrome diagnosed before the age of 46, and a family history of tumors associated with Li Fraumeni syndrome
    • Li Fraumeni syndrome associated tumors are:
      • Soft tissue sarcoma
      • Osteosarcoma
      • CNS tumor
      • Breast cancer
      • Adrenocortical carcinoma

Informed consent following genetic counseling is strongly recommended. The person in the family with the earliest diagnosis of a Li Fraumeni syndrome-related cancer should be tested first whenever possible.

Question 3. Whom can I ask for help regarding a specific case?

You can ask one of our genetic counselors. Please call Quest Genomics Client Services at 866.GENE.INFO to talk with a genetic counselor.

Question 4. What is the cancer risk associated with a positive result (pathogenic or likely pathogenic variant detected)?

Both women and men with a TP53 gene mutation have a higher risk of cancer. The overall risk of cancer for men is 69% to 95% by age 70. The overall risk for women is 83% to 95% by age 70. Cancer can occur at any age, even in infancy.

Question 5. When is the right time to test a patient?

The right time is different for every patient. A patient’s current medical status, personal experience with cancer, and general readiness for genetic information all influence the decision to be tested. Having an open dialogue about these topics between healthcare providers and patients can assist with shared decision making.

Question 6. My patient has a positive result. What does this mean?

Patients with a positive result (pathogenic or likely pathogenic mutation detected) have an increased risk for developing certain cancers relative to that of the general population.

The National Comprehensive Cancer Network (NCCN) provides up-to-date surveillance and management recommendations (http://www.nccn.org). Patient referral to an oncology center experienced in treating patients with a hereditary predisposition to cancer may be considered. Such a center can discuss available options with the patient. These options may include increased surveillance and prophylactic surgery. Genetic counseling for family members is advised.

Question 7. My patient has a negative result. What does this mean?

A negative result means that a pathogenic or likely pathogenic mutation was not found in the TP53 gene. Implications of this result depend on the situation:

  • Patients previously diagnosed with cancer: The risk of recurrence or a related new cancer is based on the patient’s personal and family histories of cancer. In some instances, it may be appropriate to test for other hereditary forms of cancer. Please call Quest Genomics Client Services at 866.GENE.INFO to discuss possible additional studies with a genetic counselor.
  • Patients not previously diagnosed with cancer, but with a family history of cancer: Testing an affected family member is recommended for proper risk assessment. A patient’s risk of cancer is based on his/her personal and family histories of cancer. In some instances, it may be appropriate to test for other hereditary forms of cancer. Please call Quest Genomics Client Services at 866.GENE.INFO to discuss possible additional studies with a genetic counselor.

Question 8. My patient has a variant of unknown clinical significance (VUS). What does this mean?

A VUS result means that the variant has not been previously described in the literature or that the clinical significance is unclear based on currently available evidence. Medical management decisions should be based on personal and family history. Family studies may be indicated to better understand the clinical significance of this variant. If you have questions, please call Quest Genomics Client Services at 866.GENE.INFO to speak with a genetic counselor.

References

  1. Bougeard G, Renaux-Petel M, Flaman JM, et al. Revisiting Li-Fraumeni Syndrome From TP53 Mutation Carriers. J Clin Oncol. 2015;33:2345-2352.
  2. National Comprehensive Cancer Network (NCCN Guidelines®). NCCN Clinical Practice Guidelines in Oncology. Genetic/Familial High-Risk Assessment: Breast and Ovarian. Version 2.2017. www.nccn.org. Accessed March 24, 2017.
This FAQ is provided for informational purposes only and is not intended as medical advice. A physician’s test selection and interpretation, diagnosis, and patient management decisions should be based on his/her education, clinical expertise, and assessment of the patient.
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Effective 04/17/2017 to present