Sperber died Tuesday night after a long battle against the disease, her publicist told "Entertainment Tonight."
Sperber most recently guest-starred on NBC's "Will & Grace," "ET" said.
She founded the weSPARK Cancer Support Center in Sherman Oaks, Calif., in 2001.
"The memory of Wendie Jo is that of a walking inspiration," Hanks said in a statement. "She met the challenges of her illness with love, cheer, joy, altruism through weSPARK, and an unstoppable supply of goodness. We are going to miss her as surely as we are all better for knowing her."
Astronomers offer more expansive view of universe
Handler slams Piers Morgan: 'You're a terrible interviewer'