Maureen Reagan, 60, the daughter of the former president and his first wife, actress Jane Wyman, is in a California hospital, where she is battling melanoma, a deadly and aggressive form of skin cancer, according to a statement issued by the Alzheimer's Association, for which she is national spokeswoman. (Ronald Reagan suffers from that disease.) Doctors found a "metastatic malignant" tumor the size of a ping-pong ball inside Reagan, said the statement, which added that the lymph nodes between her right knee and groin have been surgically removed. This is Reagan's second fight with this form of cancer. In 1996 she was treated. This occurrence resurfaced last October.