Jessica Whelan was diagnosed with Stage 4 Neuroblastoma in September 2015. She has since undergone months of chemotherapy.
This Saturday, officers will go head-to-head with their colleagues from the fire, ambulance and prison service for a night of boxing at BAE in Salmesbury.
Sixteen novice fighters will take to the ring after months of training in a bid to raise thousands of pounds to help improve the quality of life for Jessica, who lives in Oswaldtwistle.
PCSO Tom Archer of Highercroft policing team has helped to organise the event.
He said: “I am privileged to have the chance to fundraise for a cause which is extremely close to my heart.
“I am also very thankful to friends, family and colleagues who have got involved to try and make a real difference for Jessica and her family.”
To make a donation, visit htttps://crowdfunding.justgiving.com/jessicas-fight