AIM To establish the expermental model in vitro for the study of mechanism of antitumor drug resistance and the screening of antitumor drug. METHODS By continuously exposing cells to gradually increasing concentration of drug and agar cell colony forming technique, using dye exclusive method for determing cytotoxic effect, a murine leukemia L1210 cell subline were established,which exhibited 40 fold resistance to Cis diamminedichloro platinum(DDP). RESULTS The doubling times, plate efficiency, cell cycle, DNA index and cell morphology of DDP resistant L1210 subline were similarto those of its parant cell line. When the cell subline was stored with DDP at -196℃ for 6 months and then was recovered, its characterization of antitumor drug resistance was still maintained to a period of 5 months without DDP. DDP resistant L1210 subline was characterized with cross resistance to Carboplatin, Mitomycin, Thio Tepa, Methotrexate, Vincristin and Mustine Hydrochloride, but with no cross resistance to Harringtonine and Adriamycin. It was seemed more sensitive to Cytarabine and Fluorouracil. CONCLUSION DDP resistant L1210 subline is a good experimental model in vitro for the study of mechanism of antitumor drug resistance and the screening of antitumor drug.

Objective:To investigate the clinicopathological features, treatment programs and prognosis of patients with primary diffuse large B-cell lymphoma (DLBCL) in cavernous sinus.Methods:The clinical data of a patient with primary DLBCL in cavernous sinus who were admitted to Wuhan No.1 Hospital in December 2020 were retrospectively analyzed, and the relevant literature was reviewed.Results:The patient was a 63-year-old female who underwent resection of the cavernous sinus lesion, and the pathological diagnosis was DLBCL. The patient received 6 courses of R-CHOP regimen chemotherapy, lumbar puncture + intrathecal injection of chemotherapy drugs, and twice additional rituximab immunochemotherapy, and no tumor cells were found in the results of liquid-based thin layer cytology for cerebrospinal fluid exfoliated cells; twice magnetic resonance imaging (MRI) re-examination after the operation showed no recurrence and adjacent metastasis of the tumor. The patient's symptoms were significantly improved without residual neurological sequelae.Conclusions:Primary DLBCL in cavernous sinus is rare in clinical practice, early diagnosis is crucial for the prognosis of patients, and different protein expression may indicate the prognosis. Biopsy, complete resection of the tumor under the premise of preserving important anatomical structures and functions, and standardized chemotherapy combined with intrathecal injection local chemotherapy can effectively prolong the survival time of patients and improve the quality of life.