John Daley jr. is a sturdy young man with a shock of dark brown hair, an easy laugh and an overwhelming eagerness to make visitors comfortable. "Can I get you a soft drink?" "Where would you like to sit?" "That's the dog; his name is Rooney." "Is it hot outside?" Did you have any trouble finding the house . . . ?"

Aside from slight problems with his balance, Daley seems entirely recovered from the walnut-sized tumor that is still on his brain stem. His doctors said the tumor is not growing and is clinically quiet. No one knows if it will become active again.

Daley jogs every now and then in his comfortable Bethesda neighborhood near Glen Echo, and he has just begun a summer job in Washington. He loves Mount St. Mary's College in Emmitsburg, Md., where he will be a sophomore this fall, majoring in English.

He would like to be a writer, and he doesn't let uncertainty about his future interfere with his activities or ambitions.

"I don't worry about a recurrence," he said, his smile fading just a little. "I don't know if there will be or not, but I'd rather not think about it."

Daley knows firsthand of the danger of a tumor recurring. He was 7 when doctors first found the tumor, and it disappeared after they treated it with radiation. But when he was 14, it came back.

"It was nerve-wracking," he recalled. "You thought it was gone, and then it's back."

The tumor was inoperable because of its location, but doctors did remove part of a cystaround the tumor. Daley still has two tubes underneath his skin that drain the cyst and carry the fluid to his abdominal cavity.

But the operation, and other conventional treatments, didn't help. The tumor and the cyst put pressure on his brain stem, and he lost his sense of balance. To walk the 20 steps from the living room to the den, he had to plan every step carefully so that he wouldn't fall down. At Walt Whitman High School in Bethesda, he used a wheelchair to get around.

Meanwhile, the tumor was growing worse. It seemed that he would die.

As a last-ditch measure, his physician, Dr. Lucius F. Sinks, tried cis-platinum, an experimental chemotheraphy drug that doctors had used against other forms of cancer but never for brain tumors. Every three weeks, Daley went to the hospital for three days and received the drug directly in his bloodsteam.

He grew better, and by the time he developed kidney damage five months later and had to be taken off cis-platinum he was on the mend.

"I got stronger," he remembered. "From the wheelchair I graduated to a cane, and then I didn't even need that anymore. Everything kind of fell into place.

"A lot of problems people my age have seem picayune, problems you almost want to have," he said, flashing a smile. "Now that I can walk again, everything seems much easier. What more could you want?"