Tumors can present with symptoms of low-grade fever, but low-grade fever is not necessarily a tumor. The causes of low fever are: 1. Non-infectious factors: such as hyperthyroidism, autonomic nervous system dysfunction, immune system diseases, etc. 2. Infectious diseases: such as tuberculosis, chronic viral hepatitis, chronic focal infection, typhoid fever, paratyphoid fever and so on. After suffering from tumor, the body resistance will be reduced, which will lead to bacterial or viral infection and low fever symptoms; in addition, the tumor will also release inflammatory mediators to trigger oncogenic fever, which will lead to low fever symptoms. Therefore, the symptoms of low fever are not necessarily tumors, and the symptoms of low fever need to go to the hospital in time for relevant examinations to find out the causes of low fever and carry out targeted treatment.