Justin Bieber mourns cancer death of six-year-old 'wife'

WASHINGTON (AFP) - Teen idol Justin Bieber on Wednesday mourned the death of a six-year-old cancer patient who snagged his heart after she became his make-believe wife.

"One of the greatest spirits I have ever known is gone... RIP Avalanna. I love you," said Bieber on his Twitter account after the family of Avalanna Routh announced her passing on the microblogging site.

Routh, a native of Merrimac, Massachusetts, was nine months old when she was diagnosed with atypical teratoid rhabdoid tumour, or AT/RT, a rare brain disorder that usually kills its victims within a year.

Doctors at the Dana-Farber Cancer Institute in Boston, using a multi-prong therapy regimen that in some cases has overcome the tumour, succeeded in prolonging the child's life.