On October 8, Washington The number of children with cancer survivors in the United States is increasing, with an overall survival rate of more than 85% five years following diagnosis. Nevertheless, survivors may still be more susceptible to a variety of diseases, such as further malignancies.
Using data from the Childhood Cancer Survivor Study (CCSS) and the St. Jude Lifetime Cohort Study (St Jude Life), researchers at St. Jude Children’s Research Hospital discovered a genetic explanation for why a small percentage of survivors are more likely to develop second cancers, which may be more severe or fatal.
The research was published in The Lancet Oncology and will aid in genetic counselling, testing, and the implementation of customised cancer screening and prevention strategies.
According to research from the St Jude group, cancer survivors who have pathogenic (destructive) genetic variations in certain genes, also known as cancer-predisposing variants, have a higher chance of having a second cancer as adults. These second malignancies are also more likely to be severe and lethal.
The researchers had previously discovered that survivors were more likely to get a second or subsequent cancer if they possessed pathogenic mutations in one of 127 DNA damage repair genes or one of 60 distinct cancer-predisposing genes. This work expands previous research by demonstrating a direct link between cancer-predisposing mutations and increased mortality from second cancer.
It is well recognised that several of these genetic variations cause cancer. One of the 60 genes examined, for instance, is the tumour suppressor gene TP53.
The key to the discovery’s applicability is that these mutations are present in patients’ DNA when they are diagnosed with cancer as youngsters, enabling the early development of individualised treatment plans for each survivor.
The research will contribute to efforts to avoid secondary malignancies and enhance outcomes in these people by improving our knowledge of the impact that such genes may have on future cancer risk and its outcomes beyond original childhood cancer.
According to senior corresponding author Zhaoming Wang, PhD, of the St. Jude Department of Epidemiology and Cancer Control, “our study clearly shows that clinical genetic testing to screen for and determine if survivors are carriers of these pathogenic variants could lead to screening and early interventions for those at higher risk of developing deadly second cancers, potentially saving their lives.”
The proportion of childhood cancer survivors who possess cancer-predisposing mutations is modest (6%), as is the overall number of survivors who go on to acquire second or subsequent malignancies.
It has been very difficult to investigate and comprehend the hereditary risks for second malignancies and their outcome in this group as a result of these variables working together. Wang and his colleagues combined whole genome/exome sequencing with clinical data from more than 12,000 paediatric cancer survivors to arrive at statistically significant findings.
The CCSS and St. Jude LIFE cohorts, two of North America’s biggest survival studies, provided data for the research.
“This is the first comprehensive study looking for the genetic reason for late mortality, specifically late mortality due to second cancers,” Wang said. “Now we know that cancer-predisposing variants contribute to the risk of death from second cancer.” The effect of these cancer-predisposing mutations may be reduced as childhood cancer survivors age via increased monitoring. Healthcare professionals may be able to offer personalised cancer screening if they are aware of which survivors are more at risk. This might result in the identification of new malignancies at their earliest and most curable stages.
These variations are a component of the germline, or inherited, DNA that is present at birth. It follows that they may be found in kids when they are initially diagnosed with childhood malignancies, providing survivors with the information they need to reduce their risk in later life.