Methods
ONCOLOGY
The study was approved both by the University of Milan Ethical Committee (CE_26_21 and CE 84/21) and the Institutional Review Board of the European Institute of Oncology (R90/14-IEO102), in accordance with the relevant guidelines and regulations, and individual written informed consent was obtained from all the study participants after appropriate information concerning the study was provided. Eligible participants were people of either gender, older than 7 years; in the case of minors, written informed consent was provided by a legal tutor. Participation to provide a sweat sample or to be sniffed by trained dogs was volunteer. Anti-COVID-19 vaccination was not an exclusion criterium. Whenever possible, the type, number of dose and date of vaccine administration were also recorded after the information was provided on a voluntary basis.)