. . . " diagnosed with breast cancer, Poirier poured his heart out on an online message board.???It is very difficult living with the tought that i took part in this ground polution and facing death from this cancer,??? he wrote, his fingers stumbling over the keys. ???I joined the USMC to serve and protect, not to harm.???Mike Partain, one of the men who appeared in the NBC piece, tried to reassure Poir" .