Early detection of ovarian cancer is key in fighting that fatal disease...researchers have made a breakthrough in that early detection...Randall Pinkston has that story and more in today's health watch report.NEW RESEARCH MAY ONE DAY OFFER A BETTER WAY OF DETECTING OVARIAN CANCER.SCIENTISTS AT YALE UNIVERSITY HAVE DISCOVERED A NEW GENETIC MARKER THEY SAY IS PRESENT IN 25 PERCENT OF ALL OVARIAN CANCER PATIENTS.FINDING THE NEW MARKER IS IMPORTANT BECAUSE IT COULD ONE DAY HELP DOCTORS SPOT THE DISEASE SOONER.RIGHT NOW IT IS DIFFICULT TO DIAGNOSE AND ISN'T DISCOVERED UNTIL AN THE ADVANCED STAGE.SCIENTISTS BELIEVE A CERTAIN GENE MAY HELP ALZHEIMER'S PATIENTS . EXPERIMENTS ON MICE SHOW THAT WHEN THE GENE, KNOWN AS SIRT 1, IS OVERPRODUCED IN THE BRAIN, LEARNING AND MEMORY IMPROVED. RESEARCHERS BELIEVE THAT DRUGS THAT ACTIVATE THE SIRT 1 GENE MAY SOMEDAY BE ABLE TO ALLEVIATE ALZHEIMERS.PEOPLE WHO ARE FEELING BLUE MAY BE SEEING GRAY. RESEARCHERS HAVE DISCOVERED THAT VICTIMS OF DEPRESSION HAVE TROUBLE DETECTING THE CONTRAST BETWEEN BLACK AND WHITE.APPARENTLY, RETINAS OF DEPRESSED PEOPLE ARE LESS SENSITIVE TO CHANGING LIGHT PATTERNS. -THE DISCOVERY COULD LEAD TO MORE ACCURATE DIAGNOSIS OF DEPRESSION.AND THOSE ARE SOME OF THE DAY'S TOP MEDICAL STORIES. I'M RANDALL PINKSTON, CBS NEWS, NEW YORK.