Small stocks were mixed Wednesday and largely kept pace with the confused broader market, staying flat to negative for much of the day before climbing into positive territory.

Seattle-based biotech Dendreon ( DNDN) was the day's biggest loser overall, and one of the most furiously traded, after the Food and Drug Administration asked for additional clinical data on its prostate-cancer vaccine Provenge before granting approval. Shares plummeted 62% to $6.78.

The Russell 2000, of which Dendreon is a component, was nevertheless higher by 0.4% at 834.41. The S&P SmallCap 600 rose 0.5% to 433.32.

Another small biotech, Curis ( CRIS), got a black eye after Proctor & Gamble ( PG) decided to end its collaboration with the Cambridge, Mass., company, citing an unacceptable safety profile for the hair-growth compounds thus far developed under the agreement. Curis shares plunged 20.5% to $1.47; P&G lately added 0.7% to $62.19.

Oil-and-gas driller Toreador Resources ( TRGL) lost 15.1% to $13.13 after swinging to a steep first-quarter loss, largely blamed on a dry exploration well, against Wall Street's upside expectations from Thomson Financial. The Dallas-based company also filed for a $49.2 million shelf offering after the close Tuesday.

Also reporting lower-than-expected first-quarter bottom lines were Illinois-based TreeHouse Foods ( THS), recently sliding 9% to $29.07, and Hawaii's Hoku Scientific ( HOKU), a clean-energy-technologies developer, giving up 12.2% to $4.43.

Still, a number of small names ratcheted up on impressive earnings. California-based Trio-Tech International ( TRT), purveyor of semiconductor-testing and burn-in services, posted fiscal third-quarter earnings of $1.1 million, or 33 cents a share, compared with a nickel share last year. Revenue more than doubled to $13.6 million. Shares rocketed 28.2%, or $4.59, to $20.85.

BluePhoenix Solutions ( BPHX), an Israel-based business-software firm, jumped 14.3% to $9.70 on mounting non-GAAP profits of 13 cents a share, which skids past the only analyst's estimate for 7 cents. The company separately announced that chief financial officer Iris Yahal will resign from that position, to be replaced by Varda Sagiv.

Elsewhere, Wisconsin-based medical-equipment maker TomoTherapy ( TTPY) surged 22.7% after its initial public offering, which priced some 11.7 million shares at $19 apiece. The offering includes an underwriters' option for another 1.8 million shares to cover any overallotments.

Among others riding high on first-quarter results, St. Louis-based Stereotaxis ( STXS) pared its per-share loss to 31 cents from 47 cents last year and bested the Street's sales targets. Shares leapt 10.9% to $11.61.

Virginia-based coal miner James River Coal's ( JRCC) loss was far narrower than two analysts had forecast, sending shares higher by 10.9% to $10.76, and San Francisco's FiberTower ( FTWR), which sells services to wireless carriers, also reported a smaller-than-expected loss. Shares climbed 12% to $5.15.