(the following is from the ACS website)
The American Cancer Society Relay For Life^® offers the opportunity to remember people who have lost their lives to cancer and honor those who have won their battle. One of the most moving parts of the event is the Luminaria Ceremony of Hope. As the sun sets over campsites and darkness falls, the night is brightened by the glow of illuminated bags called luminaria, each of which has a special meaning. Some celebrate the lives of those who have battled cancer and have lived to tell their stories. Many remember the lives of those who have been lost to this disease. All represent someone special who has been profoundly affected by cancer and the family and friends who continue to fight back in their honor.