"We remain willing to consider additional value if given the opportunity to enter discussions and perform due diligence," said Severin Schwan, CEO of Roche Group.

Proxy advisory firm Institutional Shareholder Services (ISS) said on Friday in its recommendation to reject the offer that Roche's $6.7 billion bid for San Diego-based Illumina undervalues the firm.

Schwan said Roche was disappointed over the recommended rejection of the bid for Illumina. But "we are pleased that ISS noted that Roche would seem to be an excellent partner for Illumina as the sequencing industry grows more intertwined with new drug development," he said.

Swiss-based Roche is the world's largest maker of cancer drugs and Illumina is a maker of machines that search the human genome for ways to defeat disease.

Roche bid $44.50 per share early in the year and bumped the offer to $51 at the end of March. Illumina, whose stock was listed at $52.33 per share at Thursday's close, rejected both offers. Roche said the latest offer represented an approximate $6.8 billion bid "on a fully diluted basis."

Roche also has nominated a slate of candidates who will seek election to Illumina's board of directors at the April 18 meeting and proposed certain other matters, the statement said.

(Reporting By Sam Nelson; Editing by Sandra Maler)

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