Asian shares held recent gains but lost momentum on Tuesday as investors remained cautious ahead of the release of the U.S. inflation data and mid-term elections, which will determine control of Congress. London and New York are set to open lower with FTSE futures and E-mini futures for the S&P 500 index down 0.55% and 0.18%, respectively, after Wall Street's buoyant Monday close. MSCI's gauge of Asia Pacific stocks outside Japan narrowed gains to rise 0.12% at 0517GMT. "The thing to watch ... will be the U.S. midterms today and the CPI data tomorrow," said Redmond Wong, Saxo Markets' market...