BETHPAGE, N.Y. — Two lease renewals totaling 210,628 square feet have been signed at 1055 Stewart Avenue, an office building located in Bethpage. Briarcliffe College renewed its lease for 116,500 square feet and Northrop Grumman Systems Corp. renewed its lease for 94,128 square feet. Briarcliffe College has occupied the building for 15 years and Northrop Grumman has occupied it for 10 years. The landlord, Tilles & Zuckerbrot, was represented by Sholom & Zuckerbrot Realty. Philip Heilpern of CB Richard Ellis represented the tenant in both transactions. Approximately 20,000 square feet remains for lease at the building.