That's where David Wasilewski found himself. After co-founding women's apparel company Spanx and helping grow the brand to more than $150 million in sales, David set his sights on cancer research. Learn how this entrepreneur shifted from Spanx to founding WhatNext, the leading online source of firsthand insights to cancer treatments. David discusses how he built a brand and took his idea to market, as well as how to overcome the challenges of entrepreneurship.