Platinum Chemotherapy Leaves Lasting Genomic Scars in Children's Livers, Study Finds
核心洞察
A new Science study using NanoSeq sequencing found platinum chemotherapy left an average of 2,200 mutations per liver sample in children treated for hepatoblastoma (搜索), a burden typical of adult livers.
Mutation load rose with platinum exposure, with children receiving both cisplatin and carboplatin showing more mutations than those given cisplatin alone.
Liver cells carried far more mutations than blood cells despite systemic treatment, suggesting the liver processes or repairs platinum damage differently.
Platinum-based chemotherapy (搜索) agents cisplatin and carboplatin, which transformed the prognosis of pediatric hepatoblastoma (搜索) from a five-year survival rate of 20% to more than 80% for localized tumors, leave a lasting mutational footprint in the healthy liver tissue of treated children, according to a study published Thursday in Science.
The research examined children who received platinum therapy followed by surgery to remove their tumors. Investigators sampled both healthy and cancerous liver tissue along with patient blood, analyzing the samples using a DNA sequencing technique called NanoSeq. Results were compared against children treated with different drugs, children who received no treatment before surgery, and fetal liver tissue.
Platinum Exposure Ages Liver Cells
Exposure to platinum agents produced hundreds of mutations in genes, averaging 2,200 per liver sample — a mutational burden normally observed in adult livers. The authors describe this as platinum effectively aging the liver cells of treated children, making them resemble adult liver cells.
Mutation load increased proportionally with platinum exposure. Children who received only cisplatin carried fewer mutations than those who received both cisplatin and carboplatin. According to the authors, these mutations could raise the likelihood of liver pathologies or the emergence of secondary tumors.
"We found lots of cancer genes but also genes associated with long-term changes in liver metabolism," said Foad Rouhani, a study author and professor at King's College in London. He cautioned against overinterpreting the finding: "By no means does that mean that these cells will definitely become cancerous in time. All we talk about is there was evidence for potential for these cells to eventually cause problems further down the line."
Liver More Affected Than Blood
Liver cells showed substantially more mutations than blood cells, despite chemotherapy being a systemic treatment. "The platinum is doing something differently to liver cells than other cells. Either it's been metabolized differently or the liver cells are repairing differently, we don't really know yet," Rouhani said. He noted two possible interpretations: the liver may be more susceptible to platinum's effects, or the extent of mutations may explain why that liver became diseased in the first place.
In an accompanying perspective article, Sanjeev Vasudevan and Donald Williams Parsons, both professors at Baylor College of Medicine in Houston, wrote that the findings "provide strong evidence for conducting survivorship studies of children that have undergone treatment for liver cancer beyond their third decade of life."
For the study authors, the primary contribution is establishing that the damage occurs, enabling clinicians to monitor these patients more closely throughout their lifetimes and identify issues at an earlier stage, Rouhani said. The work also raises a prospective treatment question. "If we understand the mechanism, can we then eventually be able to design next-generation chemotherapies which are highly effective at treating the cancer but actually leave the background tissue largely untouched?" Rouhani said.
Chemotherapy Signatures Tracked in 544 Patients
Separately, research published in Nature analyzed more than 600 tumors from 544 patients in Canada, Australia and the United States, combining whole genome sequencing with detailed medical records and computational methods developed at SickKids (搜索). The team identified distinct genomic signatures of DNA changes left behind by different chemotherapies, with some patterns appearing as early as 91 days after treatment began.
"There's a long-standing belief that paediatric cancers are genetically quiet because they haven't had much time to mutate," said lead author Dr. Adam Shlien, Senior Scientist, Genetics & Genome Biology and a Lab Director in Genome Diagnostics at SickKids (搜索). "Instead, it was mind-blowing to see how many mutations found in tumors that had relapsed or spread were linked to the chemotherapy used to treat the cancer in the first place."
Until now, researchers had not known how much DNA damage is linked to chemotherapy exposure or when and how treatment-resistant tumors emerge in childhood cancer. The signatures serve as records of how cancer cells responded to therapy; once recorded, clinicians can track them and identify cancers evolving in ways that make them more likely to resist treatment, spread or return.
"We spent years analyzing the data and developing new computational methods to pinpoint these subtle patterns and connect them to specific therapies," Shlien said, describing the work as what he believes is the world's largest exploration of therapy signatures in childhood cancer using whole genome sequencing. The study was enabled by access to detailed chemotherapy exposure information — therapy type, dose and timing — from families, the majority of whom participated in the SickKids (搜索) Kids Cancer Sequencing (KiCS) program.
Toward Earlier Intervention
Researchers suggest the genomic signatures may eventually function as biomarkers forming an early warning system for children undergoing cancer treatment. "Ultimately the goal is for clinicians to use these to identify those patients where they could de-escalate chemotherapy and intervene as early as three months if they see concerning genomic signatures," said Layeghifard.
In the future, that could mean a blood test for patients of any age facing chemotherapy. The research team validated their findings in independent datasets that included adult patients. "We ultimately believe these findings will have tremendous clinical value for adult cancers treated with similar drugs," Shlien said.
"Every tumour is unique and is driven by its own biology based on where it originated and how it evolved," Shlien said. "When we treat it with chemotherapy, the interaction between tumour and treatment changes its makeup and evolutionary pathway. Defining that interaction could help clinicians detect important signals of future outcomes long before they become clinically visible."