A reflection on the work of Gianni Bonadonna from the viewpoint of the global challenge of adolescents and young adults with cancer.

Adolescents and young adults (AYAs - ages 15 to 39) constitute approximately 40% of the world's population and contribute an estimated one million new cases of cancer annually, the great majority in low- and middle-income countries (LMICs). In high-income countries (HICs) cancer is the commonest cause of disease-related death in AYAs, though overall 5-year survival rates now exceed 80%. A very different circumstance likely holds in LMICs, but accurate assessments are not readily available.Breast cancer accounts for 40% of tumours in female AYAs and this age group includes the peak incidence of Hodgkin lymphoma. The late Professor Gianni Bonadonna contributed importantly to improved survival in patients with these two diseases. Accordingly, he would be justifiably proud of the advances in AYA oncology that are being made in Italy, especially the impact of his colleagues at the Istituto Nazionale dei Tumori (INT). The initiatives of the Associazione Italiana Ematologia Pediatrica and the Società Italiana Adolescenti con Malattie Onco-ematologiche are particularly noteworthy, with the accomplishment of productive collaboration between paediatric and adult cancer care providers serving as a model for other countries to emulate.Exporting these advances can be successful through the vehicle of "twinning": establishing sustainable cooperation between institutions in HICs and partners in LMICs. Colleagues in Monza and at INT have been leaders in such programmes for decades. Cancer in AYAs remains a global challenge to which Gianni Bonadonna surely would have risen with enthusiasm and leadership while securing measurable achievements.