Susan Wojcicki, the former YouTube chief executive officer and longtime Google executive, has died, her husband said. She was 56.

“My beloved wife of 26 years and mother to our five children left us today after 2 years of living with non small cell lung cancer,” Dennis Troper said in a social media post late Friday.

“Susan was not just my best friend and partner in life, but a brilliant mind, a loving mother, and a dear friend to many,” Troper said.