PMS2 positivity indicates the presence of genetic defects, indicating the presence of microsatellite instability and insensitivity to fluorouracil, which is of some significance in guiding postoperative targeted therapy as well as chemotherapy for colorectal cancer. PMS2 is a genetic test that can be used together with mlh1, msh2 and msh6 to determine the condition of colorectal cancer, and is one of the tests in immunohistochemical examination of colorectal cancer. Generally speaking, a positive pms2 indicates the existence of genetic defects, which means that microsatellites are unstable and less sensitive to fluorouracil, and then doctors can make suitable treatment plans for patients according to the specific test results, such as targeted therapy or chemotherapy. However, when choosing drugs, it is better not to use fluorouracil drugs, so as not to affect the therapeutic effect. It is recommended to treat and use the medication under the guidance of a doctor.