LOS ANGELES (Reuters) – One after another, shortly after a diagnosis of breast cancer, each of the women learned that her health insurance had been canceled. First there was Yenny Hsu, who lived and worked in Los Angeles. Later, Robin Beaton, a registered nurse from Texas. And then, most recently, there was Patricia Relling, a successful art gallery owner and interior designer from Louisville, Kentucky. None of the women knew about the others. But besides their similar narratives, they had something else in common: Their health insurance carriers were subsidiaries of WellPoint, which has 33.7 million policyholders -- more than...