* Core CPI data points to firming inflation trends
* Crude falls 4 pct; energy, materials lead losses
* Applied Materials jumps on outlook, props Nasdaq
* Dow down 0.31 pct, S&P down 0.15 pct, Nasdaq up 0.39 pct (Updates to early afternoon)
By Abhiram Nandakumar
Feb 19 (Reuters) - The Dow and S&P 500 slipped on Friday as a renewed slide in oil prices weighed on energy and materials stocks and prospects of a rate hike this year were rekindled by data pointing to firmer inflation trends.
The Nasdaq eked out a gain, led by heavyweights Amazon and Facebook and as Applied Materials jumped 9.4 percent on the chip equipment provider's buoyant forecast.
Seven of the 10 major S&P sectors were lower. The energy sector fell 1.63 percent and the materials sector dropped 1 percent.
Still, all three major indexes were set to post their best weekly performance this year, with Nasdaq poised for its biggest weekly gain since July.
Crude prices, which have moved in lockstep with the stock market for much of the year, slid about 4 percent as U.S. crude stockpiles hit a record high.
A report showed rising rents and healthcare costs lifted underlying inflation in January, signs of a pick-up in price pressures that could allow the Federal Reserve to gradually raise rates this year.
"Right now, we're in a spot of relative uncertainty," said Gordon Charlop, a managing director at Rosenblatt Securities in New York.
"I think a lot of this action relates to "we're getting towards the end of earnings season, we've seen some macro data and we're also trying to figure out what the personality is of 2016"," he said.
At 12:39 p.m. ET (1739 GMT), the Dow Jones industrial average was down 50.54 points, or 0.31 percent, at 16,362.89
The S&P 500 was down 2.8 points, or 0.15 percent, at 1,915.03.
The Nasdaq Composite index was up 17.40 points, or 0.39 percent, at 4,504.94.
Department store operator Nordstrom dropped 6.5 percent to $49.27 after posting disappointing holiday-quarter results.
Trinity Industries slumped 25 percent after the railcar maker's forecast missed expectations. That also derailed the stocks of other rail companies.
Declining issues outnumbered advancing ones on the NYSE by 1,678 to 1,291. On the Nasdaq, 1,626 issues rose and 1,034 fell.
The S&P 500 index showed eight new 52-week highs and four lows, while the Nasdaq recorded 19 new highs and 39 lows. (Reporting by Yashaswini Swamynathan and Abhiram Nandakumar in Bengaluru; Editing by Savio D'Souza)