The Perils of Stem Cell Tourism: Case Report

Megan Brooks

June 30, 2016

A new case report describes a patient who developed a glioproliferative neoplasm of the spinal cord after stem cell transplants at commercial clinics in China, Argentina, and Mexico.

The 66-year-old man was seeking to ease residual deficits from ischemic stroke when he visited these clinics, where he underwent intrathecal infusions of mesenchymal, embryonic, and fetal neural stem cells, according to clinic reports.

He wasn't given any immunosuppressive drugs and subsequently developed the glioproliferative neoplasm.

This case highlights the risks of "stem-cell tourism," say the authors of a letter to the editor describing the case, published online June 22 in The New England Journal of Medicine.

Commercial stem-cell clinics now operate worldwide with limited or no regulation, Aaron L. Berkowitz, MD, PhD, and colleagues from Brigham and Women's Hospital, Boston, Massachusetts, point out in their letter.

After his stem cell treatments, the patient experienced progressive lower back pain, paraplegia, and urinary incontinence. MRI revealed a lesion of the thoracic spinal cord and thecal sac, and a biopsy specimen was obtained.

Risky Business

Neuropathologic analysis showed a densely cellular, highly proliferative, primitive neoplasm with glial differentiation. "Short tandem repeat DNA fingerprinting analysis indicated that the mass was predominantly composed of nonhost cells," the authors say.

On the basis of histopathologic and molecular studies, the glioproliferative lesion appeared to have originated from the intrathecally introduced exogenous stem cells.

"The lesion had some features that overlapped with malignant gliomas (nuclear atypia, a high proliferation index, glial differentiation, and vascular proliferation) but did not show other features typical of cancer (no cancer-associated genetic aberrations were detected on next-generation sequencing of 309 cancer-associated genes)," they note.

So while the lesion may be a considered a neoplasm, it didn't fit in any category of previously described human neoplasm on the basis of the data they had, Dr Berkowitz and colleagues say.

The patient underwent radiation therapy, which led to a decrease in back pain, improved mobility of the right leg, and decreased the bulk of the lesion on MRI.

"Embryonic and other stem cells have tumorigenic potential and have been proposed as a source of common origin for cancer," the authors note. This case and others in which tumors have developed in the context of stem-cell tourism illustrate "an extremely serious complication of introducing proliferating stem cells into patients," they caution.

"The unregulated commercial stem-cell industry is not only potentially harmful to individual patients," they conclude, "but also undermines attempts to study stem-cell therapies in clinical trials.

They say this case further supports the conclusions of a recent article calling for increased investigation of commercial stem-cell clinics and increased patient education regarding the risks of stem-cell tourism. "Such experimental treatments must be studied in a safe, regulated environment," Dr Berkowitz and colleagues conclude.

N Engl J Med. Published online June 22, 2016. Full text

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