Mississauga ON-based YM Biosciences Inc is being acquired by Gilead Sciences Inc, Foster City CA, for $510 million — the latest promising Canadian biotech firm to be purchased by a foreign buyer. Founded in 1994, YM Biosciences has developed CYT387, a therapeutic treatment for myelofibrosis — a progressive chronic bone disorder — and has reported positive results for the compound in a Phase I/II clinical trial. Gilead will buy the company with cash on hand, with the deal expected to close in Q1/13. Gilead has been expanding its oncology R&D expertise in recent years through acquisitions, external scientific partnerships and the appointment of leading cancer researchers and clinicians. YM had $125.5 million in cash as of September 30/12....