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PALB2, CHEK2, ATM, and TP53 (other inherited breast cancer genes) testing: what it means for you

Waiting on test results can feel like one more hard thing, for you and the people who love you. Here's what the PALB2, CHEK2, ATM, and TP53 (other inherited breast cancer genes) test looks for and how it can help your care team pick the treatment most likely to work for you.

ℹ️ General information to help you and your loved ones talk with your care team, not medical advice. Read our disclaimer.

Matters most in: Breast cancer

Why it matters

Finding one of these changes can feel like a lot to take in, and it's okay to give yourself time. It doesn't mean your cancer was your fault, and it doesn't mean everyone in your family will get cancer. It does give you and your loved ones useful information. Each gene raises breast cancer risk by a different amount. For example, PALB2 and TP53 changes are linked with a higher risk, while CHEK2 and ATM changes are usually linked with a more moderate risk. TP53 changes (Li-Fraumeni syndrome) can also raise the risk of several other cancers. Depending on the gene and your family history, your team may suggest earlier or extra screening (such as breast MRI), talk with you about ways to lower risk, and plan care for your other breast. Because these changes run in families, parents, brothers, sisters, and children can choose to be tested too. A genetic counselor can explain what your result means for you and your family, before and after testing.

Treatments it can point to

• For advanced breast cancer with an inherited PALB2 change, some experts consider a PARP inhibitor such as Lynparza (olaparib). PARP inhibitors are FDA-approved for inherited BRCA1 or BRCA2 changes, not PALB2, so ask your oncologist whether it fits you (Lynparza (olaparib))
• CHEK2 and ATM changes are not currently a reason to use a PARP inhibitor in breast cancer. Your treatment is still guided mainly by your ER, PR, and HER2 results
• With a TP53 change, your team may talk with you about limiting radiation when there are other good choices, because people with Li-Fraumeni syndrome can be more sensitive to it
• Results can also shape surgery choices, such as whether to consider removing both breasts, which is a personal decision to make with your team

Only your care team can say which treatment fits you. Drug approvals depend on cancer type, stage and prior treatment.

Tissue vs. blood testing

Blood or saliva (a germline test). If a gene change is found only in a tumor test, ask whether a blood or saliva test is needed to see if it's inherited. NCCN recommends inherited BRCA1, BRCA2, and PALB2 testing for everyone with metastatic breast cancer. Genetic counseling before and after testing is recommended.

Most tests use a piece of tumor tissue from a biopsy or surgery. Some can also use a blood sample (a 'liquid biopsy') that looks for tumor DNA floating in the blood. Blood tests are easier and faster, but they can miss a change that a tissue test would find, so a negative blood test is often followed by a tissue test.

❓ Questions you and your loved ones can ask

• Should I have a multigene panel test, not just BRCA1 and BRCA2?
• What does my PALB2, CHEK2, ATM, or TP53 result mean for my risk and screening?
• Could a PARP inhibitor help me?
• Should my family members see a genetic counselor or be tested?
• When will my results be back, and will treatment wait for them?
• Will my insurance cover this test?

Written by the Cancer Side Effects Guide team from FDA labels and leading cancer centers. Not medical advice. · Last updated: October 15, 2026 · How we write