Cancer start-up Grail added one of Silicon Valley's best-known biotech VCs to its board

Grail, a start-up that's raising over $1 billion to work on early cancer detection, has just brought on veteran venture capitalist Brook Byers to its board of directors, according to an SEC filing.

The filing on Wednesday also revealed that Grail's total amount raised in its current round has increased to $973 million from $914 million in mid-March.

Byers, a co-founder of Silicon Valley venture firm Kleiner Perkins Caufield & Byers, previously invested in companies including GHDX ,Foundation Medicine, Pacific Biosciences and Electronic Arts. He is no longer an active partner at the firm.

Grail's aim is to develop so-called liquid biopsies for spotting cancer in the earliest stages by detecting circulating fragments of tumor DNA in the blood. 

The company, led by former Google executive Jeff Huber, was originally an offshoot of Illumina, which develops supercomputers for genomic sequencing.

Huber, who led the teams in charge of Google Maps and its ad software, joined Grail after losing his wife to colon cancer.

Grail now sits just shy of its stated goal to raise over $1 billion in the round. The company is using the capital for research and development, as well as for large-scale clinical trials to prove that its technology is both sensitive and accurate.

Ken Drazan, Grail's chief business officer, confirmed that Byers joined the board on his own -- not on behalf of Kleiner Perkins -- and said the company has not yet closed its Series B funding round. Byers didn't immediately respond to a request for comment.

Drazan said the additional came from new investors, such as family offices, professional investors and crossover investors.

Byers' son Blake Byers, who works for Alphabet's venture arm GV, is backing a rival start-up. GV recently participated Freenome's $65 million funding round that was led by Andreessen Horowitz through its new bio fund.