By the time Laura Tasheiko discovered the lump in her left breast, it was larger than a grape. Tasheiko, 61, an artist who makes a living selling oil paintings of Maine's snowy woods, lighthouses and rocky coastline, was terrified: She had no health insurance and little cash to spare. But that was nearly six years ago, and the state Medicaid program was generous then. Tasheiko was eligible because of her modest income, and MaineCare, as it is called, paid for all of her treatment, including the surgery, an $18,000 drug to treat nerve damage that made it impossible to hold a paintbrush, physical therapy and continuing checkups.