Which statement correctly differentiates germline testing from somatic tumor testing and gives an example of how each informs management?

Which statement correctly differentiates germline testing from somatic tumor testing and gives an example of how each informs management?

• A. Germline testing detects inherited variants present in all cells and informs overall cancer risk, surveillance, and risk-reducing options; somatic testing analyzes tumor DNA for mutations that guide targeted therapies, such as PARP inhibitors in BRCA-mutant tumors, without implying inherited risk.
• B. Germline testing detects somatic mutations in tumor tissue; somatic testing detects inherited variants, informing only family risk.
• C. Germline testing informs treatment decisions; somatic testing informs risk assessment.
• D. Germline testing and somatic testing are the same and interchangeable.

Answer: (A)

Testing distinguishes inherited risk from tumor-specific changes. Germline testing looks for variants present in all cells and passed through the germline, so a pathogenic finding informs the patient’s overall cancer risk, guides enhanced surveillance, and triggers cascade testing for relatives along with possible risk-reducing options. For example, a germline BRCA1/2 pathogenic variant means higher lifetime risk for breast and ovarian cancer and can lead to discussions about earlier, more intensive screening and procedures to reduce risk, as well as testing family members. Somatic tumor testing, by contrast, analyzes mutations that exist only in the tumor DNA. These results help choose targeted therapies for the cancer itself—such as using PARP inhibitors when the tumor harbors BRCA mutations—even if those mutations are not present in the germline. Importantly, somatic findings do not imply inherited risk for relatives. So the best statement captures that germline findings affect patient and family risk management, while somatic findings guide tumor-directed treatment, with PARP inhibitors given as an example for BRCA-mutant tumors. The idea that germline testing detects somatic changes, or that both tests are interchangeable, does not fit the distinction.

Testing distinguishes inherited risk from tumor-specific changes. Germline testing looks for variants present in all cells and passed through the germline, so a pathogenic finding informs the patient’s overall cancer risk, guides enhanced surveillance, and triggers cascade testing for relatives along with possible risk-reducing options. For example, a germline BRCA1/2 pathogenic variant means higher lifetime risk for breast and ovarian cancer and can lead to discussions about earlier, more intensive screening and procedures to reduce risk, as well as testing family members.

Somatic tumor testing, by contrast, analyzes mutations that exist only in the tumor DNA. These results help choose targeted therapies for the cancer itself—such as using PARP inhibitors when the tumor harbors BRCA mutations—even if those mutations are not present in the germline. Importantly, somatic findings do not imply inherited risk for relatives.

So the best statement captures that germline findings affect patient and family risk management, while somatic findings guide tumor-directed treatment, with PARP inhibitors given as an example for BRCA-mutant tumors. The idea that germline testing detects somatic changes, or that both tests are interchangeable, does not fit the distinction.