50 Cent postpones European tour

US rapper 50 Cent has "temporarily postponed" his European tour, prompting questions over whether he has retired from making music.The star is currently poised to lose a chart battle with rival Kanye West. He vowed to quit if his album, Curtis, was outsold by West's Graduation.West topped the UK charts on Sunday, and he is expected to win the race to number one in the US later this week.A