Abstract
Introduction
Malignant tumors are detrimental to people’s lives and health. In recent years, pediatric cancers have emerged as the leading cause of disease-related morbidity and mortality in children, second only to accidents in developed countries. 1 In contrast to most adult cancers—the majority of which are of epithelial origin and usually develop over time due to cancer risk factor exposure—most pediatric solid tumors are considered to have an embryonic or developmental origin as alterations in organogenesis or normal growth can result in the generation of these tumors from any of the 3 germ cell lineages. 2,3 Given the advances in multimodal therapy for pediatric oncology patients, cure rates or the 5-year survival rates for pediatric cancers have increased to approximately 80% in recent decades. 4,5 However, the prognosis of many pediatric high-risk solid tumors remains poor. 6
Pediatric solid tumors are typically heterogeneous and are characterized by occult onset, high malignancy, and complex and diverse clinical manifestations. Most malignant abdominal solid tumors are found in children aged 1 to 5 years, with neuroblastoma being the most common, followed by Wilms’ tumor, hepatoblastoma and rhabdomyosarcoma. 7 Neuroblastoma is the most common malignant tumor in infancy and the most prevalent extracranial solid malignancy in childhood. 8 Neuroblastoma mainly originates from neural crest progenitor cells in the sympathetic nervous system and primarily occurs in the adrenal gland, followed by the mediastinum, neck, lower extremities, and other nerve tissues. 9,10 The prognosis of neuroblastoma patients varies greatly from spontaneous regression without treatment to rapid malignant progression—in spite of aggressive multimodal therapy. 11 Wilms’ tumor, usually derived from the embryonal nephric mesenchyme, is the fourth most frequently diagnosed pediatric malignant tumor worldwide and account for 7%-8% of the tumors in childhood. 12 This tumor is widely believed to arise as a result of erratic and disordered kidney development, in which posterior renal blastocysts fail to differentiate into glomeruli and renal tubules. 13 Hepatoblastoma, a typical embryonic tumor, accounts for nearly 80% of the pediatric liver malignancies and 1% of all childhood tumors. 14,15 Given that the exact etiology and mechanisms underlying the development of these malignant abdominal solid tumors remain unknown, elucidation of the pathogenesis and identification of more susceptible genes is imperative.
Growing evidence from genome-wide association studies (GWASs) has highlighted the importance of germline variations in disease susceptibility. As a result, considerable advances have been made in our understanding of the genetic underpinnings of pediatric malignant solid tumors.
Materials and Methods
Study Subjects
This case-control study was approved by the Institutional Review Board of Hunan Children’s Hospital, Changsha, China (IRB number: HCHLL-2020-80), and informed consent was obtained from the guardians of all participants. All patients at our hospital who were histopathologically diagnosed with neuroblastoma, Wilms’ tumor, or hepatoblastoma were included in this study. Importantly, all patients were younger than 18 years of age, and none of them had a history of any other tumors. Information regarding the major clinical characteristics of the patients, including age, sex, tumor sites, and tumor stage, was collected. In total, 250 patients with abdominal solid tumor and 270 controls were separately recruited from Hunan Children’s Hospital. The abdominal solid tumor patients comprised those with neuroblastoma (n = 162), Wilms’ tumor (n = 60), and hepatoblastoma (n = 28). The healthy controls were randomly chosen among age- and sex-matched children living in the same area as the abdominal solid tumor patients, with match age and sex. The demographic and clinical characteristics of all participants are provided in Supplemental Table 1.
SNP Selection and Genotyping
Based on previous publications, the Arg72Pro polymorphism of
Statistical Analysis
The chi-square test was performed to test for deviations from the Hardy-Weinberg equilibrium in the genotype frequencies of the polymorphism in control participants along with differences in demographic variables between the case and control subjects. The association between the Arg72Pro polymorphism of
Results
Patient Characteristics
This study included 250 patients with pediatric solid abdominal tumors and 270 cancer-free controls. The overall clinical characteristics of all participants are presented in Supplemental Table 1. For patients with neuroblastoma or Wilms’ tumor, no significant difference in age (
Association Between the Arg72Pro Polymorphism and Pediatric Abdominal Solid Tumor Risk
We successfully genotyped the 250 samples and 270 controls. The genotype frequencies of the Arg72Pro polymorphism and its associations with pediatric abdominal solid tumor susceptibility are summarized in Table 1. The genotype frequency distribution of the polymorphisms was as follows: 1) 37.65% (CC), 41.36% (CG), and 20.99% (GG) in the patients with neuroblastoma; 2) 38.33% (CC), 33.33% (CG), and 28.33% (GG) in the patients with Wilms’ tumor; 3) 32.14% (CC), 42.86% (CG), and 25.00% (GG) in the patients with hepatoblastoma; and 4) 38.89% (CC), 42.96% (CG), and 18.15% (GG) in the controls. No significant associations were identified between Arg72Pro polymorphism and pediatric solid abdominal tumor risk, even after adjusting for age and sex.
Abbreviations: OR, odds ratio; CI, confidence interval.
a χ2 test for genotype distributions between neuroblastoma cases and cancer-free controls.
b Adjusted for age and gender.
Stratification Analysis
Due to the heterogeneity of pediatric solid tumors, we further conducted a stratification analysis to investigate the association between the Arg72Pro polymorphism and pediatric abdominal solid tumor susceptibility for different subtypes. As shown in Table 2, we were unable to identify any prominent associations between the polymorphism and neuroblastoma susceptibility in all strata in both single and combined analyses. However, compared to the carriers of the CC and CG genotypes, male rs1042522 GG genotype carriers were associated with a decreased risk of developing Wilms’ tumor (adjusted OR = 2.38, 95% CI = 1.01-5.58,
Stratify Results for
Abbreviations: AOR, adjusted odds ratio; CI, confidence interval.
a Adjusted for age and gender, omitting the corresponding stratify factor.
b Clinical stage 4 s and sites of origin are just for neuroblastoma.
Values are in bold if the
Discussion
Genomic alterations across multiple childhood cancer types encourage scientists to value the genetic contribution of the host more than individual susceptibilities. Approximately half of all primary pediatric cancers harbor potentially targetable genetic events. 29 Numerous genetic polymorphisms are closely related to carcinogenesis. 30 -32 To date, the association between SNPs and susceptibility to malignant solid tumors in childhood remains poorly understood. Investigating additional polymorphisms is instrumental in furthering our understanding of genetic variations and their associations with susceptibility toward pediatric solid tumor.
Interestingly, the 2 polymorphic alleles of
Numerous studies have explored cancer susceptibility in relation to the Arg72Pro polymorphism.
40
Rosenthal et al first identified that this polymorphism dramatically affected the risk of developing cervical cancer in British women; in particular, women carrying homozygous
This polymorphism has also been well-studied in several types of childhood malignant abdominal solid tumors. Cattelani et al found that the Arg72Pro polymorphism had no effect on the risk of developing neuroblastoma by genotyping 286 patients and 288 controls.
44
This polymorphism was subsequently found to be associated with the risk of developing neuroblastoma and Wilms’ tumor but not hepatoblastoma among Chinese children.
19,21,34
However, there remains a lack of valuable evidence depicting the association between the polymorphism and the integrated risk of pediatric malignant abdominal solid tumors. To the best of our knowledge, only one study has investigated this particular association by genotyping 101 pediatric solid tumors samples and 202 controls; Borbora et al identified an SNP pair composing of
It is important to note that pediatric malignant abdominal solid tumors are heterogeneous and multi-factorial. Therefore, several limitations accompany our study. First, we only focused on the genetic factors, neglecting the environmental and genetic-environmental factors. Second, our sample size was not large enough, and we restricted the cancer types to neuroblastoma, Wilms’ tumor, and hepatoblastoma. Third, in addition to tumor tissue, other tissues should also be used as genotyping material for patients in order to reduce and eliminate significant bias in estimating the genetic effects in cancer association studies. Fourth, tumorigenesis involves variation in the expression of multiple genes, and the effect of individual gene on overall susceptibility is weak. Thus, other known polymorphisms should also be investigated, alone or in combination in the future.
Conclusion
This study demonstrated that the Arg72Pro polymorphism of
Supplemental Material
Supplemental Material, sj-pdf-1-ccx-10.1177_10732748211004880 - Association Between Arg72Pro Polymorphism in TP53 and Malignant Abdominal Solid Tumor Risk in Hunan Children
Supplemental Material, sj-pdf-1-ccx-10.1177_10732748211004880 for Association Between Arg72Pro Polymorphism in
Footnotes
Authors’ Note
Declaration of Conflicting Interests
Funding
Supplemental Material
References
Supplementary Material
Please find the following supplemental material available below.
For Open Access articles published under a Creative Commons License, all supplemental material carries the same license as the article it is associated with.
For non-Open Access articles published, all supplemental material carries a non-exclusive license, and permission requests for re-use of supplemental material or any part of supplemental material shall be sent directly to the copyright owner as specified in the copyright notice associated with the article.
