Canaccord Genuity analyst Mark Massaro recommends using the selloff today in shares of Exact Sciences as a buying opportunity. Investors were likely surprised by the celebrity choice for the marketing campaign given some investors' expectations for an "Oprah Winfrey" like celebrity, Massaro tells investors in a research note. However, after watching the promotional activities, the analyst thinks Harry and his wife, who have both been touched with cancer, are a "solid choice, particularly in the age 50-75 bracket." He reiterates a Buy rating on Exact Sciences with a $55 price target.