 On one day during his treatments , as his wife was <unk> him down a hospital corridor , Cullen went into cardiac arrest , requiring doctors to use a <unk> to revive him . He underwent a bone marrow transplant that briefly reduced his immune system to the point that he could have very little human contact . Another examination in April 1998 revealed that the cancer was finally gone , and Cullen immediately began training for a comeback . 
