When you’re in high school, selecting a prom dress can feel like one of the most important decisions you’ll ever make. But for one group of friends, the blue dress they’ll wear symbolizes much more than just an iconic teenage experience.

Catherine Malatesta — the first girl to wear the dress — rowed crew, sang in her high school choir, served as president of her student council, played field hockey and was generally loved by all who knew her, according to the Boston Globe. At just 16 years old, Catherine noticed a sharp pain in her shoulder. That pain turned out to be a symptom of a rare, aggressive form of cancer that had spread to her lungs and spine.

Even though her prognosis was grim, Catherine refused to lose hope. Throughout her brutal treatments, which included chemotherapy and radiation, Catherine passed her AP tests, acted in the school play, donated her hair to Locks of Love and toured colleges,