MPPE1 and colorectal neoplasm: In addition, another study found that colorectal tumors can be further sensitized to immune checkpoint therapy using a combination of low-dose chemotherapy and oncolytic HSV-1 in a mouse model of dMMR CRC, mainly through the mechanism of making tumors sensitive to immunotherapy by promoting high levels of cDC1 infiltration in tumors after treatment, and the therapeutic effect depends on the presence of cDC1s (57).