Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Gen-Probe (Nasdaq: GPRO) dropped 13% in intraday trading today after disappointing news about the company's attempt to be acquired.

So what: Gen-Probe announced on April 28 that it was pursuing "strategic alternatives" and had hired Morgan Stanley (NYSE: MS) to seek an acquirer. Today's Wall Street Journal is reporting that Novartis (NYSE: NVS) appears to be the last remaining potential acquirer and may not go through with a deal.

Now what: Gen-Probe stock popped on the news it was seeking an acquirer and has since outperformed the market by more than 20%. Potential buyers -- Life Technologies (Nasdaq: LIFE) and Thermo Fisher Scientific (NYSE: TMO) reportedly probed the deal but are now out of the picture -- may be balking at the price. With EPS expected to grow only 15% over the next three to five years, it would take a lot of synergy and cost savings to justify the purchase at the current P/E ratio of 37 times.

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Fool contributor Cindy Johnson does not own shares of any company named above. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.