ABC News' Lindsey Ellerson reports: The Senate’s second oldest member, U.S. Senator Frank Lautenberg, D-N.J., has been diagnosed with stomach cancer and will begin treatment immediately. “After several days of hospitalization and testing, Senator Lautenberg’s doctors have diagnosed that he has a B-Cell Lymphoma of the stomach. This is a curable tumor, and will require treatment over the next few months,” read a statement released from the senator’s office today. On Tuesday, the 86-year old Democrat underwent an endoscopy procedure after being diagnosed with a bleeding ulcer, according to Communications Director Caley Gray, who promised Lautenberg would “make a full recovery and will be back to work soon.” The Senator is currently being treated by Dr. James F. Holland and Dr. Martin Goldman of Mount Sinai Medical Center. "We expect a full and complete recovery,” Dr. Holland said in a written statement. “The Senator will be treated with chemotherapy administered approximately every three weeks. We anticipate that he will receive between six and eight treatments, and in between treatments, the Senator is expected to be back at work in the Senate.” New Jersey now has a Republican governor, Gov. Christopher Christie, sworn into office just last month after beating out Democratic incumbent Jon Corzine. Should there be a vacancy, current state law grants the governor power to make a temporary appointment, or call a special election. With Lautenberg’s age in mind, Garden State Democrats recently attempted to advance a bill that would force Christie to select a Democrat should there be a Senate vacancy, but the state lawmakers were unsuccessful. Serving the Senate since 1982, Lautenberg is the first New Jersey senator to be elected to five terms. The senator will be 90 when his term ends in 2014.