Shares of Seattle Genetics (NASDAQ:SGEN) have traded progressively higher this year, but tonight the rubber could meet the road if reported sales of lead cancer treatment Adcetris do not support guidance. The company will report earnings after the close today, and even if sales are in-line with expectations, any caution by the company on sales in future quarters could indicate that lofty long-term expectations for Adcetris are at risk. Since May’s low of $18.77, when the company first missed earnings expectations by a wide margin, SGEN has climbed 27.9% to Tuesday’s $24.33 closing price. Now the company’s market cap is approximately $2.85 billion, which may significantly overstate the true value of the business. The rise in SGEN over the past couple of months has been driven by reset sales expectations and the hope of future indications for Adcetris. Should expectations need to come down again post earnings, SGEN could fall sharply. (more…)