In addition, the center has "sister" agreements with St. Jude Children's Research Hospital in Memphis, Tenn., a pioneer in the treatment of children with cancer, and Rady Children's Hospital in San Diego.

St. Jude's provides training for Tijuana's staff through courses given in Memphis or Chile and donates grants to supplement the salaries of 18 of the 35 staff members, he said.

Meanwhile, Rady provides surgical support when a child in Tijuana requires special technology that the Tijuana hospital does not have.

The oncology center is treating virtually all pediatric cancers, said Dr. Magdalena Montes, who is in charge of morning shift there.

On a recent Thursday she gave a tour of the center, pointing out that all ten of its rooms were filled with children ranging in age from just a few months old to age eight.

One of them was Cristian, a four-month-old who had a tumor in his abdomen. He had received chemotherapy and was improving, Montes said. Another patient was eight-year-old Jimena, who had a recently been operated at Rady's Children's Hospital for brain cancer.

Montes explained that it's crucial for the children to be in isolation in the first month after treatment because they are vulnerable to infections. Still, she added, the hospital makes accommodations so they are not alone.

"All of them are here with their parents or siblings 24 hours a day."

Some children stay as long as two months in the rooms, which are brightly lit and adorned with colorful drawings on the walls, and, of course, have toys.

Tijuana General treats half the children with cancer in the city, with the other half treated at private hospitals or those belonging to large government-sponsored health providers, such as Social Security.

The Tijuana hospital is funded by the federal government through its health program called Seguro Popular, created in 2000 to offer a health safety net for all Mexicans.

Depending on income level, the coverage is free or modestly priced, and affords treatment for children with cancer at any hospital in the country that's affiliated with Seguro Popular.

The hospital also treats children from Rosarito Beach, Tecate, and the agricultural area of San Quintín.

All that's lost on the young patients on the seventh floor. That's where small children can be seen playing with a toy airplane or car in the hallway, as if they were at home, while they battle an invisible giant.

A cancer patient plays with toy cars at the Tijuana General Hospital's newly remodeled cancer ward for children on August 18, 2011. David Maung/SanDiegoRed.com

Omar.millan@sandiegored.com