Selinexor Combined With BEAM for ASCT in R/R DLBCL With MYC Positive

Inclusion Criteria: 1. According to world Health Organization (WHO) classification of disease, diffuse large B-cell lymphoma was confirmed by histology, CR or PR after second-line and above treatment; 2. The subjects tested positive for MYC in primary or pre-transplant lymphoma lesions; 3. 18≤ age ≤65 years old, male or female; 4. ECOG score 0-2; 5. No serious organic lesions in the main organs, meeting the requirements of the following laboratory examination indicators (conducted within 7 days before treatment) : 1. White blood cell count ≥3.0×109/L, absolute neutrophil count ≥1.5×109/L, Hemoglobin ≥90g/L, platelet ≥75×109/L; 2. Total bilirubin ≤1.5× upper normal value (ULN); 3. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) ≤2.5× ULN; Bilirubin ≤1.5× ULN 4. Creatinine clearance was 44-133 mmol/L; 6. No cardiac dysfunction; 7. Life expectancy over 3 months; 8. The subject or his/her legal representative must provide written informed consent prior to conducting a special study examination or procedure. Exclusion Criteria: 1. Previously received autologous hematopoietic stem cell transplantation; 2. Suffering from serious complications or severe infection; 3. Previous treatment with selinexor; 4. Central nervous system lymphoma was excluded; 5. A history of other malignant tumors within 5 years, excluding early tumors treated for curative purposes; 6. Patients with uncontrolled cardiovascular and cerebrovascular diseases, coagulation disorders, connective tissue diseases, serious infectious diseases, etc.; 7. HBsAg, HCV or HIV positive. Positive HBV and HCV serology is allowed, but DNA/RNA testing must be negative; 8. Left ventricular ejection fraction ≦ 50%; 9. Laboratory test value during screening; ① Neutrophils \<1.5×109/L; Platelet \<75×109/L; ② Bilirubin was 1.5 times higher than the normal upper limit, transaminase was 2.5 times higher than the normal upper limit; ③ The creatinine level is higher than 1.5 times the upper limit of normal value; 10. Other concurrent and uncontrolled medical conditions considered by the investigator would affect the patient's participation in the study; 11. Psychiatric patients or other patients known or suspected to be unable to fully comply with the study protocol; 12. Pregnant or lactating women; 13. The researcher judged that the patients were not suitable for this study.