PHILADELPHIA, Dec. 28 (UPI) -- Given how little is known about the cause of brain tumors, researchers are interested in what a Rohm & Haas Co. study of Philadelphia cases will say.

The company next month will publish an exhaustive study of 12 cases of brain tumors among the staff of its Philadelphia area plant, an incidence about twice the usual rate.

The company, the nation's sixth-largest chemical maker, has not provided a preview of its findings, but the Philadelphia Inquirer Sunday published profiles of eight of the victims.

At least four had worked in or near a laboratory that developed pesticides, part of a company unit sold in 2001.

Five had similar types of tumors but other cases appear on the surface to be unrelated, the newspaper said.

Although past studies have linked some chemicals to brain tumors, the results could not be duplicated.