He died in January at 57 from leukemia, the end result of a two-year struggle against myelodysplastic syndrome, a form of cancer that affects the bone marrow.

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Mrs Berger, 61, from from Harrow, north-west London, suffers from myelodysplastic syndrome and has a combination of rare tissue types, making finding a matching donor more difficult.

BBC: Caroline and Sharon Berger