Therefore, we isolated exosomal as well as cellular DNA from four dMMR CRC cell lines with known cMNR mutation status (Additional file 2) and examined the cMNR frameshift mutation pattern of three representative MSI target genes (TGFBR2 [A10], LMAN1 [A9], MARCKS [A11]). The gene discussed is TGFBR2; the disease is colorectal carcinoma.