BOSTON ( TheStreet) -- Did you catch Jim Cramer's excellent Mad Money segment Wednesday on Exact Sciences ( EXAS)? If not, a question from Paul P. on the colon cancer diagnostic stock kicks off this week's Biotech Stock Mailbag: "Have you followed and/or have any thoughts on Exact Sciences? I've been following it and am hearing that it may be overhyped. Your thoughts would be appreciated."Exact Sciences has been one of my top small-cap picks for most of this year, ever since I met CEO Kevin Conroy in January and walked away very impressed by the way he was transforming the company. I spend nearly all my time writing about companies developing drugs to treat disease, including cancer. Exact is a great story because it's working on a non-invasive, genetic test that will help doctors discover and diagnose colon cancer at its earliest stages. That's so important because colon cancer, when caught in the precancerous stage, is entirely treatable and curable. The problem today is that existing, noninvasive tests aren't sensitive enough to catch early-stage colon cancer. Colonoscopy can do the job well, but the procedure is painful, invasive and as a result, underutilized. Only about 40% of the approximately 148,000 new cases of colon cancer diagnosed in 2008 were caught early. If Exact is successful developing its genetic test, the percentage of colon cancer cases diagnosed at an early-stage and treatable stage should rise dramatically. That's great for patients, of course, but because we talk about stocks and market value here, an accurate, noninvasive genetic test that catches precancerous lesions in the colon will be embraced by insurers that would rather pay a relatively small amount for a test than dole out wads of cash for expensive cancer treatments. So, no, I don't believe Exact Sciences is being overhyped. I recognize the stock has had a great run from $4 to $8 in the past eight weeks, so I won't be surprised if we see a breather or profit-taking, especially once the independent (external) validation studies are presented on Oct. 29. If the results from those validation studies are strong, however, Exact is going to garner even more attention from large institutional buyers who aren't necessarily price sensitive with the stock still under $10. Be mindful, also, that Exact will be looking to raise more money to fund the large clinical studies needed to get its colon cancer test approved and marketed, so a better entry point in the stock may be around the corner. Regarding the Oct. 29 presentation, what we want to see Exact Sciences' test achieve is at least 85% sensitivity to cancers and 50% sensitivity to precancerous lesions. The latter number is especially important for the reasons stated above.