Personalized treatment based on mini patient-derived xenografts and WES/RNA sequencing in a patient with metastatic duodenal adenocarcinoma

Background:Treatment guidelines for a variety of cancers have been increasingly used in clinical practice,and have resulted in major improvement in patient outcomes.However,recommended regimens(even first-line treat-ments)are clearly not ideal for every patients.In the present study,we used mini patient-derived xenograft(mini-PDX)and next-generation sequencing to develop personalized treatment in a patient with metastatic duodenal adenocarcinoma.Methods:Resected metachronous metastatic tumor tissues were implanted into SCID mice to determine the sensitivity to a variety of drug regimens.Mutation profiles were assessed using both DNA whole-exome sequencing(DNA-WES)and RNA sequencing.The results of the analyses were used to select optimal treatment for the patient with metastatic duodenal adenocarcinoma.Results:Assessment with mini-PDX models took only 7 days.The results showed high sensitivity to S-1 plus cis-platin,gemcitabine plus cisplatin and everolimus alone.The patient received gemcitabine plus cisplatin initially,but the treatment was terminated due to toxicity.The patient was then switched to treatment with S-1 alone.The overall disease-free survival was 34 months.DNA-WES and RNA sequencing identified KRAS mutation(A146T),TP53(C229Yfs*10)and RICTOR amplification in the metastatic duodenal adenocarcinoma.These findings provided further support to the results of the mini-PDX,and suggest mTOR inhibitors should be used if and when relapse eventually occurs in this patient.Conclusions:Mini-PDX model combined with WES/RNA sequencing can rapidly assess drug sensitivity in cancer patients and reveal key genetic alterations.Further research on this technology for personalized therapy in patients with refractory malignant tumors is warranted.