Due to the difficulty of sampling tissue biopsies, liquid biopsies have the potential to be used in conjunction with radiologic features in the diagnosis of PCNSL.281 Currently, ctDNA is the most frequently discussed liquid biopsy for CNS lymphomas, but several studies have failed to find a relationship between the number of ctDNAs and the diagnosis of lymphomas, etc. More attention has been paid to ctDNA mutations such as MYD88, CARD11, CD79B, etc.280,282,283. Here, MYD88 is linked to primary central nervous system lymphoma.