The Post’s Nikita Stewart reports what members of the D.C. Council apparently already knew, but the public did not: Ward 3 D.C. Council member Mary Cheh was diagnosed with breast cancer last fall. Cheh has already undergone radiation treatment and a lumpectomy at Sibley Memorial Hospital, and told Stewart that her doctors have said her prognosis is good (she’ll continue to be treated with drugs for the next five years). The Council member said she is disclosing her illness to draw attention to the need for women to be tested often. “I want to be a poster child for early detection,” she told the Post.