Funding for this research was provided by:
Cancer Research Foundation in Northern Sweden (LP 16 2139)
Received: 13 December 2019
Accepted: 30 April 2020
First Online: 24 May 2020
Ethics approval and consent to participate
: The study protocol and data handling procedures were approved by the Regional ethical review board at Umeå University, Umeå, Sweden (DNR 02–455). As the cohort is more than 20–30 years old and most of the patients have passed away, the mentioned ethics committee approved the study without consent from the patients or their relatives.
: Not applicable.
: The authors declare that they have no competing interests.