BMJ Open 2022;12:e055742. doi:10.1136/bmjopen-2021-055742Open access By analysing the whole exome and transcriptome sequencing- specific somatic mutations of fresh blood samples and tumour tissues of the enrolled patients, 20 antigen peptides sequences of 25- 31aa with the highest mutation scores will be screened out. According to the above- mentioned designed individualised neoantigen polypeptide sequence, the Fmoc solid- phase method will be used to synthesise the polypeptide. Ninhydrin colour reaction will be used for quality control. The crude peptide will be purified by high- performance liquid chro- matography (HPLC) method, then the quality of peptide will be checked by mass spectrometer (MS) and HPLC. Qualified peptides should meet two criteria: correct MS and HPLC purity above 95%. Individualised neoantigen tumour peptides for the treatment of genomic unstable solid tumours use 20 peptide mixtures. According to the Good Manufacturing Practice standard of the raw mate- rial drug, the peptides will be separated and frozen for subsequent trials. Inclusion criteria 1. Gender is not limited. 2. Patients range in age from 18 to 70 years old. 3. Patients who have progressed after comprehensive treatment and diagnosed with grade 3/4 (WHO) ge- nomic unstable (tumour mutational burden >10 or mi- crosatellite instability- high (MSI- H)) solid malignant tumours, and lack further effective treatment, or the guidelines at the time of diagnosis of the patient have no corresponding recommended treatment plan are eligible.4. There is at least one lesion that can be evaluated.