In today's episode we're not answering any questions. Instead, we're going to talk with 11-year-old twins Isabelle and Sophie Posner-Brown. When Sophie was two, she was diagnosed with a malignant brain tumor. She's had three surgeries and lots of chemotherapy, but she's been on a break from chemo for the last four years. The twins talked with But Why about what it's like to live with Sophie's illness.