Thousands of patients have stepped through City of Hope's doors to undergo hematopoietic cell transplantation and take back the life that blood disorders threaten to steal from them. Every one of those men, women and children has a story to tell, a narrative of small victories and rugged persistence through illness. These are some of the patients touched by more than three decades of transplantation advances.

Anissa Ayala

Almost 20 years have passed since the procedure that saved Anissa Ayala's life, but her remarkable story — and that of her seemingly miraculous younger sister — continues to inspire.

Diagnosed with chronic myelogenous leukemia a week before her 16th birthday in 1988, Ayala needed a bone marrow transplant to save her life. Without a donor, she would live five years at most.

No one in her family matched her tissue type, so the Ayala family searched through the National Marrow Donor Program (NMDP) and participated in bone marrow drives to find a donor.

When that yielded no answers, Ayala's parents made a daring decision: conceiving a baby in hopes the child might be a match, and a lifesaver, for their daughter.

"It was a crazy idea," Ayala later recalled to People magazine. "My mother was 42, my father had a vasectomy and the odds for a match were less than 25 percent."

Despite great odds and public controversy, Marissa Ayala was born exactly two years after her sister's initial diagnosis. And she was a perfect match.

On June 4, 1991, Anissa Ayala underwent the transplant with her 14-month-old sibling's life-giving gift. TIME magazine chronicled their tale in a cover story, and it also became the basis for a book, TV movie and feature film.

The sisters today live healthy, fulfilling lives. Anissa Ayala, cancer-free since the transplant, has since worked with the Red Cross, the NMDP (now called the Be The Match registry) and the Leukemia & Lymphoma Society, and she continues to help patients find resources and be their own advocates.

Marissa Ayala is in her third year of college and is studying speech pathology. She aspires to become a teacher. Together, the sisters continue to support and promote a variety of cancer-related causes.

Mushtaque Jivani

Mushtaque Jivani has a title worth celebrating: City of Hope's first surviving bone marrow transplant patient.

In 1976, Jivani was a young college student in Indiana when he was diagnosed with acute myeloid leukemia. His doctor gave little hope. But his cousin, a Los Angeles-based physician, heard about City of Hope's new Bone Marrow Transplantation Program and urged Jivani's family to contact the hospital.

Jivani made his way to City of Hope, and with several brothers identified as potential matches, he underwent transplantation during the program's first year. He endured high-dose chemotherapy, total body irradiation and a month of complete isolation, but it paid off: He started producing healthy marrow cells.

In the years following his transplant, Jivani celebrated ever-longer anniversaries of his survival and has remained active, running the Los Angeles Marathon in 1991, becoming a long-distance cyclist and staying fit, physically and mentally, with yoga and world travels.

He also remains a testament of hope for many facing cancer.

Said Jivani: "Thanks to City of Hope's commitment to research and its mission to care for each of us with compassion, patients are able to hear, 'Yes, it is possible to survive.'"

Kennedy Kraus

Only 8 years old, Kennedy Kraus played soccer in her hometown of Carlsbad, Calif., with the tenacity of youth. But her parents noticed their daughter was starting to bruise more easily — and her bruises took longer to heal. Blood tests showed she had severe aplastic anemia. If not treated, the condition is often fatal.

Treatment for the disorder requires a bone marrow transplant, so Kennedy's doctors started to search the marrow registry and sent her north to City of Hope.

They had little idea the donor they were seeking was 9,000 miles away.

More than a decade before Kennedy's diagnosis in 2007, a German couple — Robert and Petra Benz — heard about a young man in need of a matching marrow donor to treat his leukemia. Touched by his story, they volunteered for the bone marrow registry in 1995.

They were not a match for him, but they remained on the registry. Robert Benz's day came when he got a call from the U.S. indicating he was a match for someone who desperately needed a transplant. He agreed to donate without hesitation.

Physicians in Germany extracted his cells, which were flown immediately to City of Hope and prepared for transplantation. Kennedy quickly recovered as her body accepted the new, healthy cells.

Kennedy's mother, Terri Kraus, said she was impressed with City of Hope's staff members, who comforted and entertained Kennedy throughout the bone marrow transplantation process as if she were their own child.

In 2009, Kennedy had the chance to meet and embrace Robert Benz, who flew from Germany for City of Hope's annual Celebration of Life Bone Marrow Transplant Reunion.

The Krauses remain in touch with the Benzes and are planning to visit their new German "family." Kennedy remains healthy and is back to playing soccer at full speed.

Noted Benz: "To know someone's life was saved by my donation is the best feeling one can have."

Rodrigo Nuñez

At age 17, Rodrigo Nuñez left his home in Guanajuato, a small village in Mexico, and headed to the U.S. in search of a better life. Little did he know that his journey in 1978 would give him new purpose for that life.

Six months after arriving in central California and beginning work as a migrant laborer, Nuñez fell ill. Within a week, he was diagnosed with aplastic anemia, a potentially fatal illness in which marrow produces too few healthy blood cells.

He turned to City of Hope for help, and was touched by the compassion and kindness of its staff. "One of the nurses gave me her lunch because I had arrived after mealtime," he said. "I was so grateful, I told her, 'I am going to be just like you: I am going to become a nurse.'"

Staff members tested his family in Mexico and identified his brother as a match for a bone marrow transplant. Nuñez underwent the procedure in late 1978 and spent the following year with a generous nearby family who agreed to host him while he pursued an education.

Enrolling in high school and then graduating from Pasadena City College's nursing program, Nuñez kept the promise he made at the hospital. He has worked as a nurse at City of Hope for more than 23 years.

Today, he provides compassionate comfort and understanding to patients, possessing an empathy that stems from his personal experience.

In addition to providing care and hope to patients and survivors, Nuñez also tirelessly champions the recruitment of minority volunteers into the marrow registry and has participated in several national drives to increase awareness and funds for stem cell donation.