Osborn & Barr, an advertising firm based in St. Louis, Missouri, is facing more than 130 lawsuits over the link between its former client, Monsanto, and cases of cancer associated with Monsanto’s best-selling herbicide, marketed as Roundup.

The lawsuits were filed last week in the 22nd Circuit Court in St. Louis against Creve Coeur-based Monsanto, naming Osborn & Barr as a co-defendant, for its role in promoting the glyphosate-based herbicide.

According to the filings, Monsanto’s Roundup is carcinogenic—a designation the company adamantly disputes–and connected to non-Hodgkin lymphoma, which many of the plaintiffs were diagnosed with.

“While existing lawsuits focus on holding Monsanto liable for cancer allegedly linked to glyphosate, the inclusion of the advertising agency that helped market Roundup is a different approach in the legal battle,” St. Louis Today reports.