An office building being developed at the corner of East Main Street and Rider Avenue on the eastern end of downtown Patchogue is being acquired by New York Cancer & Blood Specialists from New York-based Signature Properties.

The oncology-hematology practice, which has offices throughout the region, was already planning on being the building’s primary tenant.

Now, it will own and occupy the entire three-story building being built at 214 East Main Street, said Neil Foley, vice president of sales for New York Cancer & Blood Specialists.

About 85 employees will work in the new building, which is expected to be completed by September 2025, Foley said.

Upon completion, the medical practice will move its breast health services from its location at 365 East Main Street in East Patchogue and provide hematology and oncology services at both locations, Foley said.

The project is one of several medical facilities planned for or already underway in downtown Patchogue.

NYU Langone and Long Island Community Hospital have begun construction work on the redevelopment of the former Burlington Coat Factory site at 199 East Main Street into an ambulatory surgery center. And Schweiger Dermatology Group opened an office at 44 West Main Street.