May 10 (Reuters) - U.S. cash differentials slipped onTuesday on thin volumes, dealers said. The move came after American Petroleum Institute data showedthat U.S. crude stocks rose last week by nearly 1.5 millionbarrels into Cushing, Oklahoma, while overall inventories roseby 3.45 million barrels. * Light Louisiana Sweet for June delivery fell12.5 cents to a midpoint of $2 and traded between $2.00 and$2.05 a barrel premium to U.S. crude futures. * Mars Sour fell 5.5 cents to a midpoint of -$3.28and traded between $3.20 and $3.25 a barrel discount to U.S.crude futures. * WTI Midland fell 7.5 cents to a midpoint of-$0.2 and traded between 15 and 25 cents a barrel discount toU.S. crude futures. * West Texas Sour fell 7 cents to a midpoint of-$1.17. It was bid at $1.35 and offered at $1.00 a barreldiscount to U.S. crude with no reported trades. * WTI at East Houston traded at $1.55 a barrel over WTI. * ICE Brent July futures rose $1.89 to settle at$45.52 a barrel. * WTI June crude futures rose $1.22 to settle at$44.66 a barrel. * The Brent/WTI spread narrowed by 57.0 centsto settle at -$0.17 (Reporting By Catherine Ngai; Editing by David Gregorio)