Basic information about the case
Cancer genetic testing Female, diagnosed in December 2019, advanced lung adenocarcinoma in December 2019, pleural fluid test showed EGFR 19 deletion mutation 2020-2021, gefitinib ** brain metastasis after one year 2021-2022, osimertinib**, bone transfer in November 2023, tislelizumab + bevacizumab** 10 months, brain progression again in November 2023, cerebrospinal fluid could not be obtained, and blood was used for genetic testingReviews (1).After the secondary drug resistance of the third generation of EGFR, 60% and 70% can be confirmed by genetic testing, and there are more than 10 clear causes of drug resistance mutations, including EGFR C797S mutations, MET amplification, HER2 amplification, ALK fusions, RET fusions, BRAF mutations and other rare types, and the guidelines recommend the use of one or more methods combined with broad-spectrum molecular detection to clarify the mechanism of drug resistance. Consensus recommendation: When tissue samples cannot be biopsied and cerebrospinal fluid is not available, blood and other samples can be selected for testing to determine the cause of drug resistance. The patient used a blood sample to test the 96 gene of the [Jiai 3000 Huimin Test] item. The results are as follows: EGFR P. is detectedE746 A750del, EML4-ALK fusion, TP53 PR273L, where EML4-ALK fusion is the cause of osimertinib resistance. 
Reviews (2).The patient's blood detected EML4-ALK fusion after tislelizumab + bevacizumab** progression, confirming that the blood sample after drug resistance is indeed an effective supplement to tissue testing. In most cases, driver genes are considered independent molecular events and are mutually exclusive. However, in clinical practice, the proportion of patients with lung adenocarcinoma who have both EGFR mutations and ALK fusions is very low. ALK fusions were detected after EGFR-TKI**, and patients could benefit from osimertinib in combination with ALK inhibitors**. If a patient does not undergo genetic testing after a blind trial after drug resistance, there may not be an opportunity to try osimertinib in combination with an ALK inhibitor** regimen. Case summaryIn this case, genetic testing was used to guide the patient from initial diagnosis to drug resistance, and clinical standard diagnosis and treatment were carried out, so that the patient could have more evidence. Genetic testing after targeting** drug resistance is beneficial: the cause of drug resistance can be found through genetic testing, and the opportunity to benefit from the later line of targeted drugs** can be obtained for the cause of drug resistance. For patients with advanced tumors, choose a reliable high-level testing company, and accurate test results can also be obtained for blood and other samples. 