KCL553 (Fig. 2c) showed a polyphyletic pattern of metastatic seeding with ovarian metastasis seeding from the founding clone of the primary tumour containing ARID1A frameshift mutation (clone 1) and BCLM (CSF cfDNA) seeding after a clonal sweep in the primary tumour comprising TP53 frameshift mutation (clone 2). The gene discussed is ARID1A; the disease is neoplasm.