Although Interleukin 2 has been available since 1976, in previous experiments doctors have concentrated on multiplying lymphocytes in general, and have not reproduced and experimented with the cells specifically associated with a malignant tumor.

The Harvard doctors said that the disease-fighting lymphocytes, although a vital part of the body's general immune system, are often oriented to combat one specific type of disease. Therefore, they said, the extraction of lung cancer lymphocytes proved very effective in fighting lung cancer as well as bolstering the body's immunity system as a whole.

Kradin, although cautioning that obstacles may lie ahead, said he sees no reason why this process cannot be adapted towards fighting other tumors.

Outside Response

Many of the doctors contacted at other hospitals and medical schools would not comment on the findings of the Harvard doctors since the study has not been made public.

But some of the doctors said the field does prove promising.

"[We're] very hopeful," said Dr. Anne J. Bradley, a doctor at the Yale Cancer Center. "We're going to be hearing a lot about it in the future."

Kradin said several factors will prohibit the immediate use of the new treatment. Such negative factors are the cost, time and effort involved in the process.

Presently, the lymphocytes must be extracted from the patient and grown in a culture of his own tissues, making mass production difficult and taking often three or four weeks and several thousand dollars to complete for a single patient.

In addition, the process has yet to be tested on other types of tumors and Kradin could not guarantee that all tumors could be similarly treated.

Kradin said future research will center on keeping the artificially grown lymphocytes alive in the body for longer periods of time by injecting Interleukin 2 directly into a tumor in addition to cultivating a sample outside the body