Roche Holding AG Tuesday said it has made an offer of about $5.7 billion in cash for Illumina Inc in order to strengthen research in the biomarkers of diseases that will yield better targeted therapies, the news reports said.

The world’s biggest cancer drug maker proposed $44.50 a share for San Diego-based Illumina or 18% more than yesterday’s closing price.

Switzerland-based drugmaker The Basel will begin a tender offer to buy all the outstanding shares after Illumina was not ready to participate in discussions about a deal, the company said. 

It also said it will nominate candidates to Illumina’s board of directors to be considered at the company’s 2012 AGM. The cancer drug maker will benefit from the buyout of Illumina .

Roche will also be able to strengthen its position in the lifescience and diagnostics market. Severin Schwan, Chief Executive of Roche said, “ The Swiss drugmaker was open to a deal of as much as $3 billion and is ready to seize the right opportunities for acquisitions.”

Citigroup Inc and Greenhill & Co are the financial advisors of Roche and Davis Polk and Wardwell LLP is providing legal advice. Roche focuses on developing medicines and diagnostics that will help patients live longer and better lives.

The company addresses the unmet medical needs through excellence in science from early detection and prevention of diseases to treatment, diagnosis and treatment monitoring.