The same year, he was awarded the university prize with the special mention for the curriculum vitae and doctoral thesis.
After his return to Italy, he became Group Leader of the Molecular and Cellular Biology Laboratory at the University of Palermo.
In 2009, he was awarded the 'L’Altra Italia – Vite da Premio', a prize to honor Italian scientific researchers for outstanding achievements.
In 2010 years, he became a pioneer in isolating and characterizing human cancer stem cells from solid tumors and in elucidating their remarkable apoptosis resistance mediated by interleukins.
Professor Stassi was Director of the Cellular and Molecular Oncology Department at the S. Maugeri Foundation, IRCCS, in Pavia, Italy until June 2012.