One under-$10 stock that's starting to challenge some major breakout levels is biotech player SIGA Technologies ( SIGA), which specializes in infectious diseases. This stock is off to a red hot start in 2012, with shares up over 28% so far on the year. (I also featured it recently in " 5 Stocks With Notable Insider Buying.") If you take a look at the chart for SIGA Technologies, you'll notice that this stock has been uptrending strong since it hit a 52-week low in October at $1.78 a share. During that uptrend, shares of SIGA have been consistently making higher lows and higher highs, which is bullish price action. Now the stock is setting up to potentially trigger a big breakout and trend significantly higher from current levels. Market players should put SIGA on their trading radar for a long biased trade if the stock takes out some near-term overhead resistance at $3.26 and then $3.58 with heavy volume. Look for volume that hits near or above its three-month average action of 548,924 shares. At last check, volume today has already eclipsed that amount and the stock has hit a high of $3.32. That puts SIGA within range of challenging $3.58 in the coming days or weeks, so watch the volume if that level gets taken out. You could be a buyer of SIGA off any weakness and simply use a mental stop right around $3 a share. That $3 level is near-term support, so using a stop right below that would be a smart move. I would add to any long positions initiated off of weakness once the stock takes out $3.58 with volume. Target a big spike if we get that breakout back towards $5.36 to $5.90 a share or possibly much higher. Keep in mind that SIGA is heavily shorted since its current short interest as a percentage of the float is 20%. That ultra high short interest could be the fuel that ignites a giant short-squeeze once $3.58 a share is taken out with volume.