Personalis, Inc. announced that John West, co-founder, CEO and member of the board of directors of the company, notified the Company of his decision to retire as CEO and a director at the end of the calendar year. Mr. West has served in the DNA sequencing field for over forty years, and co-founded Personalis with four Stanford professors in 2011. Effective December 31, 2022, Aaron Tachibana, Personalis Chief Financial Officer, will serve as interim CEO and Christopher Hall, Personalis SVP and Head, Diagnostics Business, will be promoted to President.

Mr. West will continue to serve as an advisor to the Board.