Roberto L. Alves, the mayor of Danbury and Democratic state chair, announced Tuesday that he has a form of blood cancer. “After a series of recent medical tests, I have been diagnosed with Large B-Cell Lymphoma, a serious but treatable form of cancer,” Alves said in a statement. Alves, who could not be reached for comment, indicated in his statement a desire to strike a balance between transparency and privacy. Alves won his rematch with Republican Dean Esposito in 2023. Ned Lamont named him in November 2024 as his choice to succeed Nancy DiNardo as state party chair when her term ended in January 2025.