Genentech ( DNA) blows away consensus estimates, raises its guidance ... and its stock still sells off.To understand just why that is, one must understand that, as our own Justin Ferayorni put it, the key to Genentech's stock is Avastin, Avastin and Avastin. Quite simply, the drug is vital to Genentech's existing and future revenue. After all, there are currently 130 clinical trials being conducted involving 25 tumor types, according to the company. But for investors to focus only on Avastin is misguided. U.S. sales of the colorectal-cancer fighter were short of expectations -- $423 million vs. the $439 million estimate. However, sales of the anticancer drugs Rituxan and Herceptin both came in above the consensus predictions, at $526 million and $320 million, respectively, compared with expectations of $503 million and $309 million. Seemingly lost in the examination of the earnings report was the fact that Genentech boosted its full-year guidance to what would be the equivalent of roughly $1.98 to $2.05 a share. The previous consensus on Wall Street was $1.96. That's a 55% to 60% increase in earnings over last year's $1.28 -- not bad for a nearly 30-year-old company with expected revenue of almost $9 billion.