Oro Valley-based Ventana Medical Systems, part of the Roche Group, has signed an agreement to acquire Mtm Laboratories AG, a privately held German company that markets an early-detection test for cervical cancer.

Roche will pay Mtm shareholders an upfront payment of about $180 million and up to $85 million for reaching certain performance milestones, Roche said in a news release.

The transaction is expected to close in the coming weeks. Mtm is headquartered in Heidelberg, Germany, with U.S. headquarters in Westborough, Mass.

Mtm’s tests, which identify and diagnose pre-cancerous cervical lesions, are based on a gene known as p16 that is involved in tumor suppression.

The company’s CINtec Plus Cytology kit, used to analyze Pap smears and liquid samples, is approved for clinical use in Europe but only for research in the U.S. Roche said it will seek pre-market U.S. approval of the test based on planned clinical trials. The company also is planning for pre-market approval of CINtec Histology, a similar test for biopsy tissue samples.

Mtm’s products are “highly complementary” to Roche’s Human Papilloma Virus (HPV) test for cervical cancer screening, which was launched in the U.S. in April, Roche Diagnostics Chief Operating Officer Daniel O'Day said in prepared remarks.

The use of the Mtm test could help identify significant pre-cancer or cancer conditions in patients with abnormal Pap or positive HPV results, reducing unnecessary biopsies and ensuring appropriate treatment, Roche said.