Small-cap stocks along with the major indices generally turned negative in the afternoon to erase early gains, and among the biggest decliners was Exact Sciences ( EXAS).

Shares plummeted 24.3% after the Food and Drug Administration told the Marlborough, Mass., company that its DNA technology for colorectal cancer screening, PreGen-Plus, is a medical device that needs premarket regulatory approval. Shares were down $1.46 to $4.56.

Spectrum Brands ( SPC) sank 15.9% to $4.08 after the Atlanta-based maker of Rayovac batteries and other products postponed its sale of what it had called in August an "attractive strategic asset." The company cited "recent challenging conditions in the credit markets."

Massachusetts semiconductor equipment maker Axcelis Technologies ( ACLS) dropped as well, after saying it will probably take a third-quarter loss of 8 cents a share, including a 5-cent goodwill-impairment charge related to ceasing future product development in rapid thermal processing and curing. Previous guidance called for a 2-cent profit.

Revenue is also now pegged "slightly below" the previous range of $110 million to $120 million. Analysts polled by Thomson Financial are looking for a 3 cent per-share profit, excluding special items, on $115.7 million in revenue. Shares were off 24 cents, or 4.9%, at $4.70.

The Russell 2000 and the S&P SmallCap 600, which track both Spectrum and Axcelis, recently fell 0.3% to 821.79 and 0.1% to 428.48, respectively.

But TranS1 ( TSON) rocketed more than 60% after its initial public offering, which priced 5.5 million shares at $15 apiece. Underwriters have an option for another 825,000 shares in order to cover any overallotments. Shares of the Wilmington, N.C., medical device maker were up $9.05 to $24.05.

China Techfaith ( CNTF), a wireless handset maker, leapt 23.8% on news that it scored a contract with the Chinese government to develop a law enforcement-focused pocket PC phone for police in two provinces. Techfaith expects the initial shipment to occur in December. Shares were changing hands at $7.85.

Fuel-Tech ( FTEK) was also riding high on word of a new deal. The Batavia, Ill., company said an existing utility customer in the Midwest will pay it $7.2 million for the turnkey installation of a NOxOUT ULTRA system, ultimately in support of nitrogen oxide control on a coal-fired boiler. The project is slated for completion in the second half of next year. Shares were surging $4.54, or 16.3%, to $33.28.

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