At the age of 29, she first found a lump in her breast but was misdiagnosed in 2016. One and a half years later, new symptoms began to emerge including she couldn't lift her arm and had a strong cough, which she can't treat by drug. Her condition has worsened steadily, she often had vomit. It turns out she had stage IV breast cancer with metastases in her lymph, liver, lung and bone. One doctor told her not to expect a healing. Koller, however, persisted for six months for chemotherapy, and finally four CT tests showed negative results. It seemed that her metastases had disappeared from the body. Her three last CT examinations were negative, but the killer's disease had revived and defeated him. She died in her mother's hands in April 2018 at age 34.