Amber Cliff died of cervical cancer aged 25.
She worried there was something wrong with her four years ago, because she had bleeding and abdominal pains, but her family say she was told she was too young to be tested.
Joanna Gosling spoke to Amber’s brother Josh and sister Cameron on the Victoria Derbyshire programme.
The Ashburn Medical Centre in Sunderland said they were unable to comment on individual cases, but were deeply saddened to hear of Amber’s death.
The Victoria Derbyshire programme is broadcast on weekdays between 09:00 and 11:00 on BBC Two and the BBC News channel.