When HE4 is elevated during chemotherapy for ovarian cancer, the reasons to be considered include chemotherapy resistance or insensitivity, local recurrence of the disease, metastasis of ovarian cancer, etc. Generally, according to different causes of the disease, other anti-tumor therapeutic measures, such as replacement of chemotherapy regimen, surgical treatment, targeted drug therapy, etc., will be taken. HE4 is a sensitive tumor marker used for early detection or auxiliary diagnosis of ovarian cancer. 1. If ovarian cancer is resistant or insensitive to chemotherapy, and the lesions of ovarian cancer are not effectively controlled after treatment, thus causing HE4 elevation, other chemotherapy treatment can be considered. 2. Ovarian cancer patients’ lesions recur, thus causing HE4 elevation during chemotherapy, and the recurrent lesions shall be treated by surgical resection. 3. For HE4 elevation caused by metastatic lesions, genetic testing can be considered to select targeted drug therapy, or if there is no targeted drug available, other systemic chemotherapy regimens can also be used.