To collect data of any kind from the pediatric cancer community is as easy as asking for it. This community is anxious for innovation toward kinder treatments, and they are ready to help. The next step is to make it easy to do. Engage nonprofit organizations who share research, are engaged with the wider community, are trusted and can activate their members to participate. Commit to updating participants on the impact of their participation.
The most important thing is that it is easy to participate and share data (perhaps an online form requesting data/tissue from treating institution).