The U.S. Department of Health and Human Services' Centers for Medicare and Medicaid Services (CMS) is taking a closer look at insurance giant Humana. Humana sent alarming mass mailings to people enrolled in one or more of its plans. The Humana letters claim that health care reform proposals under consideration by Congress could hurt "millions of seniors and disabled individuals [who] could lose many of the important benefits and services that make Medicare advantage health plans so valuable." CMS demanded that Humana cease "immediately all such mailings to Medicare plan members and to remove any related materials directed to Medicare enrollees from your website." CMS also warned companies offering Medicare-related plans that official mailings on plan benefits must be reviewed by CMS, and that communications "claim[ing] to convey legitimate Medicare program information ... but instead offer[ing] misleading and/or confusing opinion and conjecture" are likely violations of federal rules. Earlier this year, the public relations firm Dewey Square Group sent fake letters to the editor in seniors' names, arguing against funding cuts for the private Medicare Advantage plan. Dewey Square was working for America's Health Insurance Plans.