-Mutated Lung Adenocarcinoma With Li-Fraumeni Syndrome: The Imperative for Germline Testing in Patients With a Family History, a Case Report.

Comprehensive genomic profiling (CGP) has progressed rapidly and plays an important role in advancing precision medicine in oncology. However, CGP provides opportunities for molecular-targeted therapy, but it also unveils incidental germline findings, posing challenges and opportunities in patient care. We present the case of a 32-year-old female patient, diagnosed with stage IVB lung adenocarcinoma harboring an p.L746_A750del, who was also subsequently diagnosed with Li-Fraumeni syndrome (LFS) through CGP testing. Remarkably, despite the presence of mutation, the response to EGFR-tyrosine kinase inhibitor was poor, whereas the response to cytotoxic anticancer drugs and immunotherapy was favorable. After the diagnosis of LFS, she underwent genetic counseling and has been screened for the development of a second cancer based on the Toronto protocol. This case highlights the importance of family history interviews and considering the practice of germline genomic testing for optimal management of lung cancer patients with a hereditary cancer syndrome such as LFS. Further research is warranted to delineate the impact of germline variants on treatment outcomes and secondary cancer prevention in lung cancer.