The disappearance of the crescent on the nail has nothing to do with cancer,. Cancer is a tumor, a malignant tumor. The disappearance of the crescent moon is due to the lack of vitamins, malnutrition or anemia, and the disappearance of the crescent moon can also occur when you are recovering from a serious illness. You can go to test the trace elements. Eat more vegetables and fruits, and eat more protein-containing foods, such as eggs, lean meat, and milk. Diet must be balanced, to maintain a happy mood, do not stay up late, to ensure that sleep time and sleep quality. You can take vitamins such as: 21 gold vitamins, good survival tablets and so on to regulate.