[Location - Date:][Source:][VO:][VOICE-OVER]TRACK#1 "GOOD MORNING AMERICA" ANCHOR ROBIN ROBERTS IS FACING A NEW MEDICAL CHALLENGE. THE 51-YEAR-OLD TELEVISION PERSONALITY SAYS SHE'S BEEN DIAGNOSED WITH A BLOOD AND BONE MARROW DISEASE ONCE KNOWN HAS PRE-LEUKEMIA. ROBERTS SAYS SHE'LL UNDERGO CHEMOTHERAPY... AND SHE'LL NEED A BONE MARROW TRANSPLANT THIS FALL. ROBERTS SAID THAT HER SISTER IS A GOOD MATCH AND HAS AGREED TO DONATE BONE MARROW. THE ABC NEWS ANCHOR TOLD VIEWERS ON MONDAY THAT SHE CONTRACTED THE DISEASE THROUGH HER TREATMENT FOR BREAST CANCER FIVE YEARS AGO ROBERTS SAID "MY DOCTORS TELL ME I'M GOING TO BEAT THIS AND I KNOW IT'S TRUE." SHE HAS BEEN ON THE ABC MORNING SHOW FOR A DECADE. MOST RECENTLY, ROBERTS TEAMED UP WITH GEORGE STEPHANOPOULOS AS CO-ANCHOR.[SIGOUT/REPORTER, LOCATION, ASSOCIATED PRESS]