Marshall made history in May this year by becoming Britain's first female boxing world champion on her 21st birthday.
It was her second successive World Championship final after taking a silver medal as a teenager in 2010.
She won 30 of her 33 bouts as a welterweight before moving up to the middleweight division in 2011 with immediate success, earning a bronze medal at the European Championship.
She began 2012 by beating two-time middleweight world champion Anna Laurell in her own backyard in Sweden.
At the age of 12 she turned up to Hartlepool's Headland gym on her own, taking owner and trainer Tim Coulter by surprise as he was not used to girls turning up.
Coulter admits: "I put her in with a tough lad and hoped if she took a few whacks I wouldn't see her again. But within a few minutes of getting in the ring for the first time, I saw the aggression and desire in her."