The ability of the City of Hope National Medical Center to win hundreds of millions of dollars in disputed royalties from Genentech Inc. probably will hinge on a trial jury's interpretation of competing clauses in the parties' contract that each side has invoked to make its case.

Jury selection started last week in the Los Angeles County Superior Court trial to hear the 1999 suit, which will decide whether the company owes additional royalties to City of Hope (Duarte, Calif.). The medical center is asking for compensatory damages that could approach $500 million in royalties from DNA (South San Francisco, Calif.).